@article{ZaikinRosenblumScheffczyketal.1997,
author = {Zaikin, Alexei A. and Rosenblum, Michael and Scheffczyk, Christian and Engbert, Ralf and Krampe, Ralf-Thomas and Kurths, J{\"u}rgen},
title = {Modeling qualitative changes in bimanual movements},
year = {1997},
language = {en}
}
@article{WidmannEngbertSchroeger2014,
author = {Widmann, Andreas and Engbert, Ralf and Schroeger, Erich},
title = {Microsaccadic responses indicate fast categorization of sounds: A novel approach to study auditory cognition},
series = {The journal of neuroscience},
volume = {34},
journal = {The journal of neuroscience},
number = {33},
publisher = {Society for Neuroscience},
address = {Washington},
issn = {0270-6474},
doi = {10.1523/JNEUROSCI.1568-14.2014},
pages = {11152 -- 11158},
year = {2014},
abstract = {The mental chronometry of the human brain's processing of sounds to be categorized as targets has intensively been studied in cognitive neuroscience. According to current theories, a series of successive stages consisting of the registration, identification, and categorization of the sound has to be completed before participants are able to report the sound as a target by button press after similar to 300-500 ms. Here we use miniature eye movements as a tool to study the categorization of a sound as a target or nontarget, indicating that an initial categorization is present already after 80-100 ms. During visual fixation, the rate of microsaccades, the fastest components of miniature eye movements, is transiently modulated after auditory stimulation. In two experiments, we measured microsaccade rates in human participants in an auditory three-tone oddball paradigm (including rare nontarget sounds) and observed a difference in the microsaccade rates between targets and nontargets as early as 142 ms after sound onset. This finding was replicated in a third experiment with directed saccades measured in a paradigm in which tones had to be matched to score-like visual symbols. Considering the delays introduced by (motor) signal transmission and data analysis constraints, the brain must have differentiated target from nontarget sounds as fast as 80-100 ms after sound onset in both paradigms. We suggest that predictive information processing for expected input makes higher cognitive attributes, such as a sound's identity and category, available already during early sensory processing. The measurement of eye movements is thus a promising approach to investigate hearing.},
language = {en}
}
@misc{WarschburgerCalvanoRichteretal.2015,
author = {Warschburger, Petra and Calvano, Claudia and Richter, Eike M. and Engbert, Ralf},
title = {Analysis of Attentional Bias towards Attractive and Unattractive Body Regions among Overweight Males and Females},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-86570},
year = {2015},
abstract = {Background Body image distortion is highly prevalent among overweight individuals. Whilst there is evidence that body-dissatisfied women and those suffering from disordered eating show a negative attentional bias towards their own unattractive body parts and others' attractive body parts, little is known about visual attention patterns in the area of obesity and with respect to males. Since eating disorders and obesity share common features in terms of distorted body image and body dissatisfaction, the aim of this study was to examine whether overweight men and women show a similar attentional bias. Methods/Design We analyzed eye movements in 30 overweight individuals (18 females) and 28 normalweight individuals (16 females) with respect to the participants' own pictures as well as gender- and BMI-matched control pictures (front and back view). Additionally, we assessed body image and disordered eating using validated questionnaires. Discussion The overweight sample rated their own body as less attractive and showed a more disturbed body image. Contrary to our assumptions, they focused significantly longer on attractive compared to unattractive regions of both their own and the control body. For one's own body, this was more pronounced for women. A higher weight status and more frequent body checking predicted attentional bias towards attractive body parts. We found that overweight adults exhibit an unexpected and stable pattern of selective attention, with a distinctive focus on their own attractive body regions despite higher levels of body dissatisfaction. This positive attentional bias may either be an indicator of a more pronounced pattern of attentional avoidance or a self-enhancing strategy. Further research is warranted to clarify these results.},
language = {en}
}
@article{WarschburgerCalvanoRichteretal.2015,
author = {Warschburger, Petra and Calvano, Claudia and Richter, Eike M. and Engbert, Ralf},
title = {Analysis of Attentional Bias towards Attractive and Unattractive Body Regions among Overweight Males and Females},
series = {PLoS one},
journal = {PLoS one},
number = {10},
publisher = {Public Library of Science},
address = {Lawrence, Kan.},
issn = {1932-6203},
doi = {10.1371/journal.pone.0140813},
pages = {17},
year = {2015},
abstract = {Background Body image distortion is highly prevalent among overweight individuals. Whilst there is evidence that body-dissatisfied women and those suffering from disordered eating show a negative attentional bias towards their own unattractive body parts and others' attractive body parts, little is known about visual attention patterns in the area of obesity and with respect to males. Since eating disorders and obesity share common features in terms of distorted body image and body dissatisfaction, the aim of this study was to examine whether overweight men and women show a similar attentional bias. Methods/Design We analyzed eye movements in 30 overweight individuals (18 females) and 28 normalweight individuals (16 females) with respect to the participants' own pictures as well as gender- and BMI-matched control pictures (front and back view). Additionally, we assessed body image and disordered eating using validated questionnaires. Discussion The overweight sample rated their own body as less attractive and showed a more disturbed body image. Contrary to our assumptions, they focused significantly longer on attractive compared to unattractive regions of both their own and the control body. For one's own body, this was more pronounced for women. A higher weight status and more frequent body checking predicted attentional bias towards attractive body parts. We found that overweight adults exhibit an unexpected and stable pattern of selective attention, with a distinctive focus on their own attractive body regions despite higher levels of body dissatisfaction. This positive attentional bias may either be an indicator of a more pronounced pattern of attentional avoidance or a self-enhancing strategy. Further research is warranted to clarify these results.},
language = {en}
}
@article{WarschburgerCalvanoRichteretal.2015,
author = {Warschburger, Petra and Calvano, Claudia and Richter, Eike M. and Engbert, Ralf},
title = {Analysis of Attentional Bias towards Attractive and Unattractive Body Regions among Overweight Males and Females: An Eye-Movement Study},
series = {PLoS one},
volume = {10},
journal = {PLoS one},
number = {10},
publisher = {PLoS},
address = {San Fransisco},
issn = {1932-6203},
doi = {10.1371/journal.pone.0140813},
pages = {17},
year = {2015},
abstract = {Background Body image distortion is highly prevalent among overweight individuals. Whilst there is evidence that body-dissatisfied women and those suffering from disordered eating show a negative attentional bias towards their own unattractive body parts and others' attractive body parts, little is known about visual attention patterns in the area of obesity and with respect to males. Since eating disorders and obesity share common features in terms of distorted body image and body dissatisfaction, the aim of this study was to examine whether overweight men and women show a similar attentional bias. Methods/Design We analyzed eye movements in 30 overweight individuals (18 females) and 28 normal-weight individuals (16 females) with respect to the participants' own pictures as well as gender- and BMI-matched control pictures (front and back view). Additionally, we assessed body image and disordered eating using validated questionnaires. Discussion The overweight sample rated their own body as less attractive and showed a more disturbed body image. Contrary to our assumptions, they focused significantly longer on attractive compared to unattractive regions of both their own and the control body. For one's own body, this was more pronounced for women. A higher weight status and more frequent body checking predicted attentional bias towards attractive body parts. We found that overweight adults exhibit an unexpected and stable pattern of selective attention, with a distinctive focus on their own attractive body regions despite higher levels of body dissatisfaction. This positive attentional bias may either be an indicator of a more pronounced pattern of attentional avoidance or a self-enhancing strategy. Further research is warranted to clarify these results.},
language = {en}
}
@article{TrukenbrodEngbert2007,
author = {Trukenbrod, Hans Arne and Engbert, Ralf},
title = {Oculomotor control in a sequential search task},
doi = {10.1016/j.visres.2007.05.010},
year = {2007},
abstract = {Using a serial search paradigm, we observed several effects of within-object fixation position on spatial and temporal control of eye movements: the preferred viewing location, launch site effect, the optimal viewing position, and the inverted optimal viewing position of fixation duration. While these effects were first identified by eye-movement studies in reading, our approach permits an analysis of the functional relationships between the effects in a different paradigm. Our results demonstrate that the fixation position is an important predictor of the subsequent saccade by influencing both fixation duration and the selection of the next saccade target.},
language = {en}
}
@article{TrukenbrodBarthelmeWichmannetal.2019,
author = {Trukenbrod, Hans Arne and Barthelme, Simon and Wichmann, Felix A. and Engbert, Ralf},
title = {Spatial statistics for gaze patterns in scene viewing},
series = {Journal of vision},
volume = {19},
journal = {Journal of vision},
number = {5},
publisher = {Association for Research in Vision and Opthalmology},
address = {Rockville},
issn = {1534-7362},
doi = {10.1167/19.6.5},
pages = {1 -- 19},
year = {2019},
abstract = {Scene viewing is used to study attentional selection in complex but still controlled environments. One of the main observations on eye movements during scene viewing is the inhomogeneous distribution of fixation locations: While some parts of an image are fixated by almost all observers and are inspected repeatedly by the same observer, other image parts remain unfixated by observers even after long exploration intervals. Here, we apply spatial point process methods to investigate the relationship between pairs of fixations. More precisely, we use the pair correlation function, a powerful statistical tool, to evaluate dependencies between fixation locations along individual scanpaths. We demonstrate that aggregation of fixation locations within 4 degrees is stronger than expected from chance. Furthermore, the pair correlation function reveals stronger aggregation of fixations when the same image is presented a second time. We use simulations of a dynamical model to show that a narrower spatial attentional span may explain differences in pair correlations between the first and the second inspection of the same image.},
language = {en}
}
@article{StarzynskiEngbert2009,
author = {Starzynski, Christian and Engbert, Ralf},
title = {Noise-enhanced target discrimination under the influence of fixational eye movements and external noise},
issn = {1054-1500},
doi = {10.1063/1.3098950},
year = {2009},
abstract = {Active motor processes are present in many sensory systems to enhance perception. In the human visual system, miniature eye movements are produced involuntarily and unconsciously when we fixate a stationary target. These fixational eye movements represent self-generated noise which serves important perceptual functions. Here we investigate fixational eye movements under the influence of external noise. In a two-choice discrimination task, the target stimulus performed a random walk with varying noise intensity. We observe noise-enhanced discrimination of the target stimulus characterized by a U-shaped curve of manual response times as a function of the diffusion constant of the stimulus. Based on the experiments, we develop a stochastic information-accumulator model for stimulus discrimination in a noisy environment. Our results provide a new explanation for the constructive role of fixational eye movements in visual perception.},
language = {en}
}
@article{SinnEngbert2011,
author = {Sinn, Petra and Engbert, Ralf},
title = {Saccadic facilitation by modulation of microsaccades in natural backgrounds},
series = {Attention, perception, \& psychophysics : AP\&P ; a journal of the Psychonomic Society, Inc.},
volume = {73},
journal = {Attention, perception, \& psychophysics : AP\&P ; a journal of the Psychonomic Society, Inc.},
number = {4},
publisher = {Springer},
address = {New York},
issn = {1943-3921},
doi = {10.3758/s13414-011-0107-9},
pages = {1029 -- 1033},
year = {2011},
abstract = {Saccades move objects of interest into the center of the visual field for high-acuity visual analysis. White, Stritzke, and Gegenfurtner (Current Biology, 18, 124-128, 2008) have shown that saccadic latencies in the context of a structured background are much shorter than those with an unstructured background at equal levels of visibility. This effect has been explained by possible preactivation of the saccadic circuitry whenever a structured background acts as a mask for potential saccade targets. Here, we show that background textures modulate rates of microsaccades during visual fixation. First, after a display change, structured backgrounds induce a stronger decrease of microsaccade rates than do uniform backgrounds. Second, we demonstrate that the occurrence of a microsaccade in a critical time window can delay a subsequent saccadic response. Taken together, our findings suggest that microsaccades contribute to the saccadic facilitation effect, due to a modulation of microsaccade rates by properties of the background.},
language = {en}
}
@misc{SeeligRisseEngbert2021,
author = {Seelig, Stefan and Risse, Sarah and Engbert, Ralf},
title = {Predictive modeling of parafoveal information processing during reading},
series = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
journal = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
issn = {1866-8364},
doi = {10.25932/publishup-52666},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-526665},
pages = {11},
year = {2021},
abstract = {Skilled reading requires information processing of the fixated and the not-yet-fixated words to generate precise control of gaze. Over the last 30 years, experimental research provided evidence that word processing is distributed across the perceptual span, which permits recognition of the fixated (foveal) word as well as preview of parafoveal words to the right of fixation. However, theoretical models have been unable to differentiate the specific influences of foveal and parafoveal information on saccade control. Here we show how parafoveal word difficulty modulates spatial and temporal control of gaze in a computational model to reproduce experimental results. In a fully Bayesian framework, we estimated model parameters for different models of parafoveal processing and carried out large-scale predictive simulations and model comparisons for a gaze-contingent reading experiment. We conclude that mathematical modeling of data from gaze-contingent experiments permits the precise identification of pathways from parafoveal information processing to gaze control, uncovering potential mechanisms underlying the parafoveal contribution to eye-movement control.},
language = {en}
}
@article{SeeligRisseEngbert2021,
author = {Seelig, Stefan and Risse, Sarah and Engbert, Ralf},
title = {Predictive modeling of parafoveal information processing during reading},
series = {Scientific Reports},
volume = {11},
journal = {Scientific Reports},
publisher = {Springer Nature},
address = {Berlin},
issn = {2045-2322},
pages = {9},
year = {2021},
abstract = {Skilled reading requires information processing of the fixated and the not-yet-fixated words to generate precise control of gaze. Over the last 30 years, experimental research provided evidence that word processing is distributed across the perceptual span, which permits recognition of the fixated (foveal) word as well as preview of parafoveal words to the right of fixation. However, theoretical models have been unable to differentiate the specific influences of foveal and parafoveal information on saccade control. Here we show how parafoveal word difficulty modulates spatial and temporal control of gaze in a computational model to reproduce experimental results. In a fully Bayesian framework, we estimated model parameters for different models of parafoveal processing and carried out large-scale predictive simulations and model comparisons for a gaze-contingent reading experiment. We conclude that mathematical modeling of data from gaze-contingent experiments permits the precise identification of pathways from parafoveal information processing to gaze control, uncovering potential mechanisms underlying the parafoveal contribution to eye-movement control.},
language = {en}
}
@article{SeeligRisseEngbert2021,
author = {Seelig, Stefan and Risse, Sarah and Engbert, Ralf},
title = {Predictive modeling of parafoveal information processing during reading},
series = {Scientific reports},
volume = {11},
journal = {Scientific reports},
number = {1},
publisher = {Nature Portfolio},
address = {Berlin},
issn = {2045-2322},
doi = {10.1038/s41598-021-92140-z},
pages = {9},
year = {2021},
abstract = {Skilled reading requires information processing of the fixated and the not-yet-fixated words to generate precise control of gaze. Over the last 30 years, experimental research provided evidence that word processing is distributed across the perceptual span, which permits recognition of the fixated (foveal) word as well as preview of parafoveal words to the right of fixation. However, theoretical models have been unable to differentiate the specific influences of foveal and parafoveal information on saccade control. Here we show how parafoveal word difficulty modulates spatial and temporal control of gaze in a computational model to reproduce experimental results. In a fully Bayesian framework, we estimated model parameters for different models of parafoveal processing and carried out large-scale predictive simulations and model comparisons for a gaze-contingent reading experiment. We conclude that mathematical modeling of data from gaze-contingent experiments permits the precise identification of pathways from parafoveal information processing to gaze control, uncovering potential mechanisms underlying the parafoveal contribution to eye-movement control.},
language = {en}
}
@article{SeeligRabeMalemShinitskietal.2020,
author = {Seelig, Stefan A. and Rabe, Maximilian Michael and Malem-Shinitski, Noa and Risse, Sarah and Reich, Sebastian and Engbert, Ralf},
title = {Bayesian parameter estimation for the SWIFT model of eye-movement control during reading},
series = {Journal of mathematical psychology},
volume = {95},
journal = {Journal of mathematical psychology},
publisher = {Elsevier},
address = {San Diego},
issn = {0022-2496},
doi = {10.1016/j.jmp.2019.102313},
pages = {32},
year = {2020},
abstract = {Process-oriented theories of cognition must be evaluated against time-ordered observations. Here we present a representative example for data assimilation of the SWIFT model, a dynamical model of the control of fixation positions and fixation durations during natural reading of single sentences. First, we develop and test an approximate likelihood function of the model, which is a combination of a spatial, pseudo-marginal likelihood and a temporal likelihood obtained by probability density approximation Second, we implement a Bayesian approach to parameter inference using an adaptive Markov chain Monte Carlo procedure. Our results indicate that model parameters can be estimated reliably for individual subjects. We conclude that approximative Bayesian inference represents a considerable step forward for computational models of eye-movement control, where modeling of individual data on the basis of process-based dynamic models has not been possible so far.},
language = {en}
}
@article{SchuettRothkegelTrukenbrodetal.2017,
author = {Sch{\"u}tt, Heiko Herbert and Rothkegel, Lars Oliver Martin and Trukenbrod, Hans Arne and Reich, Sebastian and Wichmann, Felix A. and Engbert, Ralf},
title = {Likelihood-based parameter estimation and comparison of dynamical cognitive models},
series = {Psychological Review},
volume = {124},
journal = {Psychological Review},
number = {4},
publisher = {American Psychological Association},
address = {Washington},
issn = {0033-295X},
doi = {10.1037/rev0000068},
pages = {505 -- 524},
year = {2017},
abstract = {Dynamical models of cognition play an increasingly important role in driving theoretical and experimental research in psychology. Therefore, parameter estimation, model analysis and comparison of dynamical models are of essential importance. In this article, we propose a maximum likelihood approach for model analysis in a fully dynamical framework that includes time-ordered experimental data. Our methods can be applied to dynamical models for the prediction of discrete behavior (e.g., movement onsets); in particular, we use a dynamical model of saccade generation in scene viewing as a case study for our approach. For this model, the likelihood function can be computed directly by numerical simulation, which enables more efficient parameter estimation including Bayesian inference to obtain reliable estimates and corresponding credible intervals. Using hierarchical models inference is even possible for individual observers. Furthermore, our likelihood approach can be used to compare different models. In our example, the dynamical framework is shown to outperform nondynamical statistical models. Additionally, the likelihood based evaluation differentiates model variants, which produced indistinguishable predictions on hitherto used statistics. Our results indicate that the likelihood approach is a promising framework for dynamical cognitive models.},
language = {en}
}
@article{SchuettRothkegelTrukenbrodetal.2019,
author = {Sch{\"u}tt, Heiko Herbert and Rothkegel, Lars Oliver Martin and Trukenbrod, Hans Arne and Engbert, Ralf and Wichmann, Felix A.},
title = {Disentangling bottom-up versus top-down and low-level versus high-level influences on eye movements over time},
series = {Journal of vision},
volume = {19},
journal = {Journal of vision},
number = {3},
publisher = {Association for Research in Vision and Opthalmology},
address = {Rockville},
issn = {1534-7362},
doi = {10.1167/19.3.1},
pages = {23},
year = {2019},
abstract = {Bottom-up and top-down as well as low-level and high-level factors influence where we fixate when viewing natural scenes. However, the importance of each of these factors and how they interact remains a matter of debate. Here, we disentangle these factors by analyzing their influence over time. For this purpose, we develop a saliency model that is based on the internal representation of a recent early spatial vision model to measure the low-level, bottom-up factor. To measure the influence of high-level, bottom-up features, we use a recent deep neural network-based saliency model. To account for top-down influences, we evaluate the models on two large data sets with different tasks: first, a memorization task and, second, a search task. Our results lend support to a separation of visual scene exploration into three phases: the first saccade, an initial guided exploration characterized by a gradual broadening of the fixation density, and a steady state that is reached after roughly 10 fixations. Saccade-target selection during the initial exploration and in the steady state is related to similar areas of interest, which are better predicted when including high-level features. In the search data set, fixation locations are determined predominantly by top-down processes. In contrast, the first fixation follows a different fixation density and contains a strong central fixation bias. Nonetheless, first fixations are guided strongly by image properties, and as early as 200 ms after image onset, fixations are better predicted by high-level information. We conclude that any low-level, bottom-up factors are mainly limited to the generation of the first saccade. All saccades are better explained when high-level features are considered, and later, this high-level, bottom-up control can be overruled by top-down influences.},
language = {en}
}
@misc{SchuettRothkegelTrukenbrodetal.2019,
author = {Sch{\"u}tt, Heiko Herbert and Rothkegel, Lars Oliver Martin and Trukenbrod, Hans Arne and Engbert, Ralf and Wichmann, Felix A.},
title = {Predicting fixation densities over time from early visual processing},
series = {Perception},
volume = {48},
journal = {Perception},
publisher = {Sage Publ.},
address = {London},
issn = {0301-0066},
pages = {64 -- 65},
year = {2019},
abstract = {Bottom-up saliency is often cited as a factor driving the choice of fixation locations of human observers, based on the (partial) success of saliency models to predict fixation densities in free viewing. However, these observations are only weak evidence for a causal role of bottom-up saliency in natural viewing behaviour. To test bottom-up saliency more directly, we analyse the performance of a number of saliency models---including our own saliency model based on our recently published model of early visual processing (Sch{\"u}tt \& Wichmann, 2017, JoV)---as well as the theoretical limits for predictions over time. On free viewing data our model performs better than classical bottom-up saliency models, but worse than the current deep learning based saliency models incorporating higher-level information like knowledge about objects. However, on search data all saliency models perform worse than the optimal image independent prediction. We observe that the fixation density in free viewing is not stationary over time, but changes over the course of a trial. It starts with a pronounced central fixation bias on the first chosen fixation, which is nonetheless influenced by image content. Starting with the 2nd to 3rd fixation, the fixation density is already well predicted by later densities, but more concentrated. From there the fixation distribution broadens until it reaches a stationary distribution around the 10th fixation. Taken together these observations argue against bottom-up saliency as a mechanistic explanation for eye movement control after the initial orienting reaction in the first one to two saccades, although we confirm the predictive value of early visual representations for fixation locations. The fixation distribution is, first, not well described by any stationary density, second, is predicted better when including object information and, third, is badly predicted by any saliency model in a search task.},
language = {en}
}
@misc{SchwetlickTrukenbrodEngbert2019,
author = {Schwetlick, Lisa and Trukenbrod, Hans Arne and Engbert, Ralf},
title = {The Influence of Visual Long Term Memory on Eye Movements During Scene Viewing},
series = {Perception},
volume = {48},
journal = {Perception},
number = {S1},
publisher = {Sage Publ.},
address = {London},
issn = {0301-0066},
pages = {138 -- 138},
year = {2019},
language = {en}
}
@article{SchwetlickRothkegelTrukenbrodetal.2020,
author = {Schwetlick, Lisa and Rothkegel, Lars Oliver Martin and Trukenbrod, Hans Arne and Engbert, Ralf},
title = {Modeling the effects of perisaccadic attention on gaze statistics during scene viewing},
series = {Communications biology},
volume = {3},
journal = {Communications biology},
number = {1},
publisher = {Springer Nature},
address = {London},
issn = {2399-3642},
doi = {10.1038/s42003-020-01429-8},
pages = {11},
year = {2020},
abstract = {Lisa Schwetlick et al. present a computational model linking visual scan path generation in scene viewing to physiological and experimental work on perisaccadic covert attention, the act of attending to an object visually without obviously moving the eyes toward it. They find that integrating covert attention into predictive models of visual scan paths greatly improves the model's agreement with experimental data.
How we perceive a visual scene depends critically on the selection of gaze positions. For this selection process, visual attention is known to play a key role in two ways. First, image-features attract visual attention, a fact that is captured well by time-independent fixation models. Second, millisecond-level attentional dynamics around the time of saccade drives our gaze from one position to the next. These two related research areas on attention are typically perceived as separate, both theoretically and experimentally. Here we link the two research areas by demonstrating that perisaccadic attentional dynamics improve predictions on scan path statistics. In a mathematical model, we integrated perisaccadic covert attention with dynamic scan path generation. Our model reproduces saccade amplitude distributions, angular statistics, intersaccadic turning angles, and their impact on fixation durations as well as inter-individual differences using Bayesian inference. Therefore, our result lend support to the relevance of perisaccadic attention to gaze statistics.},
language = {en}
}
@article{SchiekScheffczykEngbertetal.1997,
author = {Schiek, Michael and Scheffczyk, Christian and Engbert, Ralf and Kurths, J{\"u}rgen and Krampe, Ralf-Thomas and Kliegl, Reinhold and Drepper, Friedhelm R.},
title = {Symbolic dynamics of physiological synchronisation : examples from bimanual movements and cardiorespiratory interaction},
year = {1997},
abstract = {Key words: Nonlinear time series analysis, symbolic dynamics, phase transitions, physiological data, biological synchronization, production of polyrhythms, cardiorespiratory interaction, variation of control parameter},
language = {en}
}
@article{ScheffczykKrampeEngbertetal.1997,
author = {Scheffczyk, Christian and Krampe, Ralf-Thomas and Engbert, Ralf and Rosenblum, Michael and Kurths, J{\"u}rgen and Kliegl, Reinhold},
title = {Tempo-induced transitions in polyrhythmic hand movements},
year = {1997},
abstract = {We investigate the cognitive control in polyrhythmic hand movements as a model paradigm for bimanual coordination. Using a symbolic coding of the recorded time series, we demonstrate the existence of qualitative transitions induced by experimental manipulation of the tempo. A nonlinear model with delayed feedback control is proposed, which accounts for these dynamical transitions in terms of bifurcations resulting from variation of the external control parameter. Furthermore, it is shown that transitions can also be observed due to fluctuations in the timing control level. We conclude that the complexity of coordinated bimanual movements results from interactions between nonlinear control mechanisms with delayed feedback and stochastic timing components.},
language = {en}
}
@article{ScheffczykEngbertKurthsetal.1995,
author = {Scheffczyk, Christian and Engbert, Ralf and Kurths, J{\"u}rgen and Krampe, Ralf-Thomas and Kliegl, Reinhold},
title = {Nonlinear Phenomena in Polyrhythmic Hand Movements},
isbn = {981-02-2689-6},
year = {1995},
abstract = {In this paper we apply symbolic transformations as a visualisation technique for analysing rhythm production. It is shown that qualitative information can be extracted from the experimental data. This approach may provide new insights into the organisation of temporal order by the brain on different levels of description. A simple phenomenological model for the explanation of the observed phenomena is proposed.},
language = {en}
}
@article{SchadNuthmannEngbert2012,
author = {Schad, Daniel and Nuthmann, Antje and Engbert, Ralf},
title = {Your mind wanders weakly, your mind wanders deeply - objective measures reveal mindless reading at different levels},
series = {Cognition : international journal of cognitive science},
volume = {125},
journal = {Cognition : international journal of cognitive science},
number = {2},
publisher = {Elsevier},
address = {Amsterdam},
issn = {0010-0277},
doi = {10.1016/j.cognition.2012.07.004},
pages = {179 -- 194},
year = {2012},
abstract = {When the mind wanders, attention turns away from the external environment and cognitive processing is decoupled from perceptual information. Mind wandering is usually treated as a dichotomy (dichotomy-hypothesis), and is often measured using self-reports. Here, we propose the levels of inattention hypothesis, which postulates attentional decoupling to graded degrees at different hierarchical levels of cognitive processing. To measure graded levels of attentional decoupling during reading we introduce the sustained attention to stimulus task (SAST), which is based on psychophysics of error detection. Under experimental conditions likely to induce mind wandering, we found that subjects were less likely to notice errors that required high-level processing for their detection as opposed to errors that only required low-level processing. Eye tracking revealed that before errors were overlooked influences of high- and low-level linguistic variables on eye fixations were reduced in a graded fashion, indicating episodes of mindless reading at weak and deep levels. Individual fixation durations predicted overlooking of lexical errors 5 s before they occurred. Our findings support the levels of inattention hypothesis and suggest that different levels of mindless reading can be measured behaviorally in the SAST. Using eye tracking to detect mind wandering online represents a promising approach for the development of new techniques to study mind wandering and to ameliorate its negative consequences.},
language = {en}
}
@article{SchadNuthmannEngbert2010,
author = {Schad, Daniel and Nuthmann, Antje and Engbert, Ralf},
title = {Eye movements during reading of randomly shuffled texts},
issn = {0042-6989},
year = {2010},
abstract = {In research on eye-movement control during reading, the importance of cognitive processes related to language comprehension relative to visuomotor aspects of saccade generation is the topic of an ongoing debate. Here we investigate various eye-movement measures during reading of randomly shuffled meaningless text as compared to normal meaningful text. To ensure processing of the material, readers were occasionally probed for words occurring in normal or shuffled text. For reading of shuffled text we observed longer fixation times, less word skippings, and more refixations than in normal reading. Shuffled-text reading further differed from normal reading in that low-frequency words were not overall fixated longer than high-frequency words. However, the frequency effect was present on long words, but was reversed for short words. Also, consistent with our prior research we found distinct experimental effects of spatially distributed processing over several words at a time, indicating how lexical word processing affected eye movements. Based on analyses of statistical linear mixed-effect models we argue that the results are compatible with the hypothesis that the perceptual span is more strongly modulated by foveal load in the shuffled reading task than in normal reading. Results are discussed in the context of computational models of reading.},
language = {en}
}
@article{SchadEngbert2012,
author = {Schad, Daniel and Engbert, Ralf},
title = {The zoom lens of attention simulating shuffled versus normal text reading using the SWIFT model},
series = {Visual cognition},
volume = {20},
journal = {Visual cognition},
number = {4-5},
publisher = {Wiley},
address = {Hove},
issn = {1350-6285},
doi = {10.1080/13506285.2012.670143},
pages = {391 -- 421},
year = {2012},
abstract = {Assumptions on the allocation of attention during reading are crucial for theoretical models of eye guidance. The zoom lens model of attention postulates that attentional deployment can vary from a sharp focus to a broad window. The model is closely related to the foveal load hypothesis, i.e., the assumption that the perceptual span is modulated by the difficulty of the fixated word. However, these important theoretical concepts for cognitive research have not been tested quantitatively in eye movement models. Here we show that the zoom lens model, implemented in the SWIFT model of saccade generation, captures many important patterns of eye movements. We compared the model's performance to experimental data from normal and shuffled text reading. Our results demonstrate that the zoom lens of attention might be an important concept for eye movement control in reading.},
language = {en}
}
@article{RothkegelTrukenbrodSchuettetal.2016,
author = {Rothkegel, Lars Oliver Martin and Trukenbrod, Hans Arne and Sch{\"u}tt, Heiko Herbert and Wichmann, Felix A. and Engbert, Ralf},
title = {Influence of initial fixation position in scene viewing},
series = {Vision research : an international journal for functional aspects of vision.},
volume = {129},
journal = {Vision research : an international journal for functional aspects of vision.},
publisher = {Elsevier},
address = {Oxford},
issn = {0042-6989},
doi = {10.1016/j.visres.2016.09.012},
pages = {33 -- 49},
year = {2016},
language = {en}
}
@article{RothkegelSchuettTrukenbrodetal.2019,
author = {Rothkegel, Lars Oliver Martin and Sch{\"u}tt, Heiko Herbert and Trukenbrod, Hans Arne and Wichmann, Felix A. and Engbert, Ralf},
title = {Searchers adjust their eye-movement dynamics to target characteristics in natural scenes},
series = {Scientific reports},
volume = {9},
journal = {Scientific reports},
publisher = {Nature Publ. Group},
address = {London},
issn = {2045-2322},
doi = {10.1038/s41598-018-37548-w},
pages = {12},
year = {2019},
abstract = {When searching a target in a natural scene, it has been shown that both the target's visual properties and similarity to the background influence whether and how fast humans are able to find it. So far, it was unclear whether searchers adjust the dynamics of their eye movements (e.g., fixation durations, saccade amplitudes) to the target they search for. In our experiment, participants searched natural scenes for six artificial targets with different spatial frequency content throughout eight consecutive sessions. High-spatial frequency targets led to smaller saccade amplitudes and shorter fixation durations than low-spatial frequency targets if target identity was known. If a saccade was programmed in the same direction as the previous saccade, fixation durations and successive saccade amplitudes were not influenced by target type. Visual saliency and empirical fixation density at the endpoints of saccades which maintain direction were comparatively low, indicating that these saccades were less selective. Our results suggest that searchers adjust their eye movement dynamics to the search target efficiently, since previous research has shown that low-spatial frequencies are visible farther into the periphery than high-spatial frequencies. We interpret the saccade direction specificity of our effects as an underlying separation into a default scanning mechanism and a selective, target-dependent mechanism.},
language = {en}
}
@article{RomanoThielKurthsetal.2006,
author = {Romano, Maria Carmen and Thiel, Marco and Kurths, J{\"u}rgen and Rolfs, Martin and Engbert, Ralf and Kliegl, Reinhold},
title = {Synchronization Analysis and Recurrence in Complex Systems},
isbn = {978-3-527-40623-4},
year = {2006},
language = {en}
}
@article{RomanoThielKurthsetal.2009,
author = {Romano, Maria Carmen and Thiel, Marco and Kurths, J{\"u}rgen and Mergenthaler, Konstantin and Engbert, Ralf},
title = {Hypothesis test for synchronization : twin surrogates revisited},
issn = {1054-1500},
doi = {10.1063/1.3072784},
year = {2009},
abstract = {The method of twin surrogates has been introduced to test for phase synchronization of complex systems in the case of passive experiments. In this paper we derive new analytical expressions for the number of twins depending on the size of the neighborhood, as well as on the length of the trajectory. This allows us to determine the optimal parameters for the generation of twin surrogates. Furthermore, we determine the quality of the twin surrogates with respect to several linear and nonlinear statistics depending on the parameters of the method. In the second part of the paper we perform a hypothesis test for phase synchronization in the case of experimental data from fixational eye movements. These miniature eye movements have been shown to play a central role in neural information processing underlying the perception of static visual scenes. The high number of data sets (21 subjects and 30 trials per person) allows us to compare the generated twin surrogates with the "natural" surrogates that correspond to the different trials. We show that the generated twin surrogates reproduce very well all linear and nonlinear characteristics of the underlying experimental system. The synchronization analysis of fixational eye movements by means of twin surrogates reveals that the synchronization between the left and right eye is significant, indicating that either the centers in the brain stem generating fixational eye movements are closely linked, or, alternatively that there is only one center controlling both eyes.},
language = {en}
}
@article{RolfsKlieglEngbert2008,
author = {Rolfs, Martin and Kliegl, Reinhold and Engbert, Ralf},
title = {Toward a model of microsaccade generation : the case of microsaccadic inhibition},
issn = {1534-7362},
doi = {10.1167/8.11.5},
year = {2008},
language = {en}
}
@misc{RolfsKlieglEngbert2004,
author = {Rolfs, Martin and Kliegl, Reinhold and Engbert, Ralf},
title = {Microsaccade orientation supports attentional enhancement opposite to a peripheral cue: Commentary on Tse, Sheinberg, and Logothetis},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-57081},
year = {2004},
language = {en}
}
@article{RolfsEngbertKliegl2005,
author = {Rolfs, Martin and Engbert, Ralf and Kliegl, Reinhold},
title = {Crossmodal coupling of oculomotor control and spatial attention in vision and audition},
issn = {0014-4819},
year = {2005},
abstract = {Fixational eye movements occur involuntarily during visual fixation of stationary scenes. The fastest components of these miniature eye movements are microsaccades, which can be observed about once per second. Recent studies demonstrated that microsaccades are linked to covert shifts of visual attention. Here, we generalized this finding in two ways. First, we used peripheral cues, rather than the centrally presented cues of earlier studies. Second, we spatially cued attention in vision and audition to visual and auditory targets. An analysis of microsaccade responses revealed an equivalent impact of visual and auditory cues on microsaccade-rate signature (i.e. an initial inhibition followed by an overshoot and a final return to the pre-cue baseline rate). With visual cues or visual targets, microsaccades were briefly aligned with cue direction and then opposite to cue direction during the overshoot epoch, probably as a result of an inhibition of an automatic saccade to the peripheral cue. With left auditory cues and auditory targets microsaccades oriented in cue direction. We argue that microsaccades can be used to study crossmodal integration of sensory information and to map the time course of saccade preparation during covert shifts of visual and auditory attention},
language = {en}
}
@article{RolfsEngbertKliegl2004,
author = {Rolfs, Martin and Engbert, Ralf and Kliegl, Reinhold},
title = {Microsaccade orientation supports attentional enhancement opposite to a peripheral cue},
year = {2004},
language = {en}
}
@article{RisseHohensteinKliegletal.2014,
author = {Risse, Sarah and Hohenstein, Sven and Kliegl, Reinhold and Engbert, Ralf},
title = {A theoretical analysis of the perceptual span based on SWIFT simulations of the n+2 boundary paradigm},
series = {Visual cognition},
volume = {22},
journal = {Visual cognition},
number = {3-4},
publisher = {Routledge, Taylor \& Francis Group},
address = {Abingdon},
issn = {1350-6285},
doi = {10.1080/13506285.2014.881444},
pages = {283 -- 308},
year = {2014},
abstract = {Eye-movement experiments suggest that the perceptual span during reading is larger than the fixated word, asymmetric around the fixation position, and shrinks in size contingent on the foveal processing load. We used the SWIFT model of eye-movement control during reading to test these hypotheses and their implications under the assumption of graded parallel processing of all words inside the perceptual span. Specifically, we simulated reading in the boundary paradigm and analysed the effects of denying the model to have valid preview of a parafoveal word n + 2 two words to the right of fixation. Optimizing the model parameters for the valid preview condition only, we obtained span parameters with remarkably realistic estimates conforming to the empirical findings on the size of the perceptual span. More importantly, the SWIFT model generated parafoveal processing up to word n + 2 without fitting the model to such preview effects. Our results suggest that asymmetry and dynamic modulation are plausible properties of the perceptual span in a parallel word-processing model such as SWIFT. Moreover, they seem to guide the flexible distribution of processing resources during reading between foveal and parafoveal words.},
language = {en}
}
@article{RisseEngbertKliegl2008,
author = {Risse, Sarah and Engbert, Ralf and Kliegl, Reinhold},
title = {Eye-movement control in reading : experimental and corpus-analysis challenges for a computational model},
isbn = {978-7-201-06107-8},
year = {2008},
language = {en}
}
@article{RichterEngbertKliegl2006,
author = {Richter, Eike M. and Engbert, Ralf and Kliegl, Reinhold},
title = {Current advances in SWIFT},
issn = {1389-0417},
doi = {10.1016/j.cogsys.2005.07.003},
year = {2006},
abstract = {Models of eye movement control are very useful for gaining insights into the intricate connections of different cognitive and oculomotor subsystems involved in reading. The SWIFT model (Engbert, Longtin, \& Kliegl (2002). Vision Research, 42, 621 - 636) proposed a unified mechanism to account for all types of eye movement patterns that might be observed in reading behavior. The model is based on the notion of spatially distributed, or parallel, processing of words in a sentence. We present a refined version of SWIFT introducing a letter-based approach that proposes a processing gradient in the shape of a smooth function. We show that SWIFT extents its capabilities by accounting for distributions of landing positions.},
language = {en}
}
@article{RichterEngbert2005,
author = {Richter, Eike M. and Engbert, Ralf},
title = {Impossible gap paradigm : Experimental evidence for autonomous saccade timing},
issn = {0301-0066},
year = {2005},
language = {en}
}
@article{RichterEngbert2004,
author = {Richter, Eike M. and Engbert, Ralf},
title = {Parafoveal processing during reading},
issn = {0301-0066},
year = {2004},
language = {en}
}
@article{RabeChandraKruegeletal.2021,
author = {Rabe, Maximilian Michael and Chandra, Johan and Kr{\"u}gel, Andr{\´e} and Seelig, Stefan A. and Vasishth, Shravan and Engbert, Ralf},
title = {A bayesian approach to dynamical modeling of eye-movement control in reading of normal, mirrored, and scrambled texts},
series = {Psychological Review},
volume = {128},
journal = {Psychological Review},
number = {5},
publisher = {American Psychological Association},
address = {Washington},
issn = {0033-295X},
doi = {10.1037/rev0000268},
pages = {803 -- 823},
year = {2021},
abstract = {In eye-movement control during reading, advanced process-oriented models have been developed to reproduce behavioral data. So far, model complexity and large numbers of model parameters prevented rigorous statistical inference and modeling of interindividual differences. Here we propose a Bayesian approach to both problems for one representative computational model of sentence reading (SWIFT; Engbert et al., Psychological Review, 112, 2005, pp. 777-813). We used experimental data from 36 subjects who read the text in a normal and one of four manipulated text layouts (e.g., mirrored and scrambled letters). The SWIFT model was fitted to subjects and experimental conditions individually to investigate between- subject variability. Based on posterior distributions of model parameters, fixation probabilities and durations are reliably recovered from simulated data and reproduced for withheld empirical data, at both the experimental condition and subject levels. A subsequent statistical analysis of model parameters across reading conditions generates model-driven explanations for observable effects between conditions.},
language = {en}
}
@article{NuthmannVituEngbertetal.2016,
author = {Nuthmann, Antje and Vitu, Francoise and Engbert, Ralf and Kliegl, Reinhold},
title = {No Evidence for a Saccadic Range Effect for Visually Guided and Memory-Guided Saccades in Simple Saccade-Targeting Tasks},
series = {PLoS one},
volume = {11},
journal = {PLoS one},
publisher = {PLoS},
address = {San Fransisco},
issn = {1932-6203},
doi = {10.1371/journal.pone.0162449},
pages = {9935 -- 9943},
year = {2016},
abstract = {Saccades to single targets in peripheral vision are typically characterized by an undershoot bias. Putting this bias to a test, Kapoula [1] used a paradigm in which observers were presented with two different sets of target eccentricities that partially overlapped each other. Her data were suggestive of a saccadic range effect (SRE): There was a tendency for saccades to overshoot close targets and undershoot far targets in a block, suggesting that there was a response bias towards the center of eccentricities in a given block. Our Experiment 1 was a close replication of the original study by Kapoula [1]. In addition, we tested whether the SRE is sensitive to top-down requirements associated with the task, and we also varied the target presentation duration. In Experiments 1 and 2, we expected to replicate the SRE for a visual discrimination task. The simple visual saccade-targeting task in Experiment 3, entailing minimal top-down influence, was expected to elicit a weaker SRE. Voluntary saccades to remembered target locations in Experiment 3 were expected to elicit the strongest SRE. Contrary to these predictions, we did not observe a SRE in any of the tasks. Our findings complement the results reported by Gillen et al. [2] who failed to find the effect in a saccade-targeting task with a very brief target presentation. Together, these results suggest that unlike arm movements, saccadic eye movements are not biased towards making saccades of a constant, optimal amplitude for the task.},
language = {en}
}
@article{NuthmannSmithEngbertetal.2010,
author = {Nuthmann, Antje and Smith, Tim J. and Engbert, Ralf and Henderson, John M.},
title = {CRISP: a computational model of fixation duration in scene viewing},
year = {2010},
abstract = {Eye-movement control during scene viewing can be represented as a series of individual decisions about where and when to move the eyes. While substantial behavioral and computational research has been devoted to investigating the placement of fixations in scenes, relatively little is known about the mechanisms that control fixation durations. Here, we propose a computational model (CRISP) that accounts for saccade timing and programming and thus for variations in fixation durations in scene viewing. First, timing signals are modeled as continuous-time random walks. Second, difficulties at the level of visual and cognitive processing can inhibit and thus modulate saccade timing. Inhibition generates moment-by-moment changes in the random walk's transition rate and processing-related saccade cancellation. Third, saccade programming is completed in 2 stages: an initial, labile stage that is subject to cancellation and a subsequent, nonlabile stage. Several simulation studies tested the model's adequacy and generality. An initial simulation study explored the role of cognitive factors in scene viewing by examining how fixation durations differed under different viewing task instructions. Additional simulations investigated the degree to which fixation durations were under direct moment-to-moment control of the current visual scene. The present work further supports the conclusion that fixation durations, to a certain degree, reflect perceptual and cognitive activity in scene viewing. Computational model simulations contribute to an understanding of the underlying processes of gaze control.},
language = {en}
}
@article{NuthmannEngbertKliegl2005,
author = {Nuthmann, Antje and Engbert, Ralf and Kliegl, Reinhold},
title = {Mislocated fixations during reading and the inverted optimal viewing position effect},
year = {2005},
abstract = {Refixation probability during reading is lowest near the word center, suggestive of an optimal viewing position (OVP). Counter-intuitively, fixation durations are largest at the OVP, a result called the inverted optimal viewing position (IOVP) effect [Vitu, McConkie, Kerr, \& O'Regan, (2001). Vision Research 41, 3513-3533]. Current models of eye-movement control in reading fail to reproduce the IOVP effect. We propose a simple mechanism for generating this effect based on error-correction of mislocated fixations due to saccadic errors, First, we propose an algorithm for estimating proportions of mislocated fixations from experimental data yielding a higher probability for mislocated fixations near word boundaries. Second, we assume that mislocated fixations trigger an immediate start of a new saccade program causing a decrease of associated durations. Thus, the IOVP effect could emerge as a result of a coupling between cognitive and oculomotor processes. (c) 2005 Elsevier Ltd. All rights reserved},
language = {en}
}
@article{NuthmannEngbertKliegl2006,
author = {Nuthmann, Antje and Engbert, Ralf and Kliegl, Reinhold},
title = {Messung von Blickbewegungen},
isbn = {978-3-8017-1846-6},
year = {2006},
language = {de}
}
@article{NuthmannEngbertKliegl2007,
author = {Nuthmann, Antje and Engbert, Ralf and Kliegl, Reinhold},
title = {The IOVP-effect in mindless reading : Experiment and modeling},
doi = {10.1016/j.visres.2006.11.005},
year = {2007},
abstract = {Fixation durations in reading are longer for within-word fixation positions close to word center than for positions near word boundaries. This counterintuitive result was termed the Inverted-Optimal Viewing Position (IOVP) effect. We proposed an explanation of the effect based on error-correction of mislocated fixations [Nuthmann, A., Engbert, R., \& Kliegl, R. (2005). Mislocated fixations during reading and the inverted optimal viewing position effect. Vision Research, 45, 2201-2217], that suggests that the IOVP effect is not related to word processing. Here we demonstrate the existence of an IOVP effect in "mindless reading", a G-string scanning task. We compare the results from experimental data with results obtained from computer simulations of a simple model of the IOVP effect and discuss alternative accounts. We conclude that oculornotor errors, which often induce mislocalized fixations, represent the most important source of the IOVP effect. (c) 2006 Elsevier Ltd. All rights reserved.},
language = {en}
}
@article{NuthmannEngbert2009,
author = {Nuthmann, Antje and Engbert, Ralf},
title = {Mindless reading revisited : an analysis based on the SWIFT model of eye-movement control},
issn = {0042-6989},
doi = {10.1016/j.visres.2008.10.022},
year = {2009},
abstract = {In this article, we revisit the mindless reading paradigm from the perspective of computational modeling. In the standard version of the paradigm, participants read sentences in both their normal version as well as the transformed (or mindless) version where each letter is replaced with a z. z-String scanning shares the oculomotor requirements with reading but none of the higher-level lexical and semantic processes. Here we use the z-string scanning task to validate the SWIFT model of saccade generation [Engbert, R., Nuthmann, A., Richter, E., \& Kliegl, R. (2005). SWIFT: A dynamical model of saccade generation during reading. Psychological Review, 112(4), 777-813] as an example for an advanced theory of eye-movement control in reading. We test the central assumption of spatially distributed processing across an attentional gradient proposed by the SWIFT model. Key experimental results like prolonged average fixation durations in z-string scanning compared to normal reading and the existence of a string-length effect on fixation durations and probabilities were reproduced by the model, which lends support to the model's assumptions on visual processing. Moreover, simulation results for patterns of regressive saccades in z-string scanning confirm SWIFT's concept of activation field dynamics for the selection of saccade targets.},
language = {en}
}
@article{MoshelZivotofskyLiangetal.2008,
author = {Moshel, Shay and Zivotofsky, Ari Z. and Liang, Jin-Rong and Engbert, Ralf and Kurths, J{\"u}rgen and Kliegl, Reinhold and Havlin, Shlomo},
title = {Persistence and phase synchronization properties of fixational eye movement},
issn = {1951-6355},
year = {2008},
abstract = {When we fixate our gaze on a stable object, our eyes move continuously with extremely small involuntary and autonomic movements, that even we are unaware of during their occurrence. One of the roles of these fixational eye movements is to prevent the adaptation of the visual system to continuous illumination and inhibit fading of the image. These random, small movements are restricted at long time scales so as to keep the target at the centre of the field of view. In addition, the synchronisation properties between both eyes are related to binocular coordination in order to provide stereopsis. We investigated the roles of different time scale behaviours, especially how they are expressed in the different spatial directions (vertical versus horizontal). We also tested the synchronisation between both eyes. Results show different scaling behaviour between horizontal and vertical movements. When the small ballistic movements, i.e., microsaccades, are removed, the scaling behaviour in both axes becomes similar. Our findings suggest that microsaccades enhance the persistence at short time scales mostly in the horizontal component and much less in the vertical component. We also applied the phase synchronisation decay method to study the synchronisation between six combinations of binocular fixational eye movement components. We found that the vertical-vertical components of right and left eyes are significantly more synchronised than the horizontal-horizontal components. These differences may be due to the need for continuously moving the eyes in the horizontal plane in order to match the stereoscopic image for different viewing distances.},
language = {en}
}
@article{MoshelLiangCaspietal.2005,
author = {Moshel, Shay and Liang, Jin-Rong and Caspi, Avi and Engbert, Ralf and Kliegl, Reinhold and Havlin, Shlomo and Zivotofsky, Ari Z.},
title = {Phase-synchronization decay of fixational eye movements},
year = {2005},
language = {en}
}
@article{MeybergSinnEngbertetal.2017,
author = {Meyberg, Susann and Sinn, Petra and Engbert, Ralf and Sommer, Werner},
title = {Revising the link between microsaccades and the spatial cueing of voluntary attention},
series = {Vision research : an international journal for functional aspects of vision.},
volume = {133},
journal = {Vision research : an international journal for functional aspects of vision.},
publisher = {Elsevier},
address = {Oxford},
issn = {0042-6989},
doi = {10.1016/j.visres.2017.01.001},
pages = {47 -- 60},
year = {2017},
abstract = {Microsaccades - i.e., small fixational saccades generated in the superior colliculus (SC) - have been linked to spatial attention. While maintaining fixation, voluntary shifts of covert attention toward peripheral targets result in a sequence of attention-aligned and attention-opposing microsaccades. In most previous studies the direction of the voluntary shift is signaled by a spatial cue (e.g., a leftwards pointing arrow) that presents the most informative part of the cue (e.g., the arrowhead) in the to-be attended visual field. Here we directly investigated the influence of cue position and tested the hypothesis that microsaccades align with cue position rather than with the attention shift. In a spatial cueing task, we presented the task-relevant part of a symmetric cue either in the to-be attended visual field or in the opposite field. As a result, microsaccades were still weakly related to the covert attention shift; however, they were strongly related to the position of the cue even if that required a movement opposite to the cued attention shift. Moreover, if microsaccades aligned with cue position, we observed stronger cueing effects on manual response times. Our interpretation of the data is supported by numerical simulations of a computational model of microsaccade generation that is based on SC properties, where we explain our findings by separate attentional mechanisms for cue localization and the cued attention shift. We conclude that during cueing of voluntary attention, microsaccades are related to both - the overt attentional selection of the task-relevant part of the cue stimulus and the subsequent covert attention shift.(C) 2017 Elsevier Ltd. All rights reserved.},
language = {en}
}
@article{MergenthalerEngbert2010,
author = {Mergenthaler, Konstantin and Engbert, Ralf},
title = {Microsaccades are different from saccades in scene perception},
year = {2010},
abstract = {Eye-fixation durations are among the best and most widely used measures of ongoing cognition in visual tasks, e.g., reading, visual search or scene perception. However, fixations are characterized by ongoing motor activity (or fixational eye movements) with microsaccades as their most pronounced components. Recent work demonstrated the similarities of microsaccades and inspection saccades. Here, we show that distinct properties of microsaccades and inspection saccades can be found in a scene perception task, based on descriptive measures (e.g., a bimodal amplitude distribution) as well as functional characteristics (e.g., inter saccadic-event intervals and generating processes). Besides these specific differences, microsaccade rates produced by individual participants in a fixation paradigm are correlated with microsaccade rates extracted from fixations in scene perception, indicating a common neurophysiological basis. Finally, we observed that slow fixational eye movements, called drift, are significantly reduced during long fixations in scene viewing, which informs about the control of eye movements in scene viewing.},
language = {en}
}
@article{MalemShinitskiOpperReichetal.2020,
author = {Malem-Shinitski, Noa and Opper, Manfred and Reich, Sebastian and Schwetlick, Lisa and Seelig, Stefan A. and Engbert, Ralf},
title = {A mathematical model of local and global attention in natural scene viewing},
series = {PLoS Computational Biology : a new community journal},
volume = {16},
journal = {PLoS Computational Biology : a new community journal},
number = {12},
publisher = {PLoS},
address = {San Fransisco},
issn = {1553-734X},
doi = {10.1371/journal.pcbi.1007880},
pages = {21},
year = {2020},
abstract = {Author summary
Switching between local and global attention is a general strategy in human information processing. We investigate whether this strategy is a viable approach to model sequences of fixations generated by a human observer in a free viewing task with natural scenes. Variants of the basic model are used to predict the experimental data based on Bayesian inference. Results indicate a high predictive power for both aggregated data and individual differences across observers. The combination of a novel model with state-of-the-art Bayesian methods lends support to our two-state model using local and global internal attention states for controlling eye movements.
Understanding the decision process underlying gaze control is an important question in cognitive neuroscience with applications in diverse fields ranging from psychology to computer vision. The decision for choosing an upcoming saccade target can be framed as a selection process between two states: Should the observer further inspect the information near the current gaze position (local attention) or continue with exploration of other patches of the given scene (global attention)? Here we propose and investigate a mathematical model motivated by switching between these two attentional states during scene viewing. The model is derived from a minimal set of assumptions that generates realistic eye movement behavior. We implemented a Bayesian approach for model parameter inference based on the model's likelihood function. In order to simplify the inference, we applied data augmentation methods that allowed the use of conjugate priors and the construction of an efficient Gibbs sampler. This approach turned out to be numerically efficient and permitted fitting interindividual differences in saccade statistics. Thus, the main contribution of our modeling approach is two-fold; first, we propose a new model for saccade generation in scene viewing. Second, we demonstrate the use of novel methods from Bayesian inference in the field of scan path modeling.},
language = {en}
}
@article{LaubrockKlieglRolfsetal.2010,
author = {Laubrock, Jochen and Kliegl, Reinhold and Rolfs, Martin and Engbert, Ralf},
title = {When do microsaccades follow spatial attention?},
issn = {1943-3921},
doi = {10.3758/APP.72.3.683},
year = {2010},
abstract = {Following up on an exchange about the relation between microsaccades and spatial attention (Horowitz, Fencsik, Fine, Yurgenson, \& Wolfe, 2007; Horowitz, Fine, Fencsik, Yurgenson, \& Wolfe, 2007; Laubrock, Engbert, Rolfs, \& Kliegl, 2007), we examine the effects of selection criteria and response modality. We show that for Posner cuing with saccadic responses, microsaccades go with attention in at least 75\% of cases (almost 90\% if probability matching is assumed) when they are first (or only) microsaccades in the cue target interval and when they occur between 200 and 400 msec after the cue. The relation between spatial attention and the direction of microsaccades drops to chance level for unselected microsaccades collected during manual-response conditions. Analyses of data from four cross-modal cuing experiments demonstrate an above-chance, intermediate link for visual cues, but no systematic relation for auditory cues. Thus, the link between spatial attention and direction of microsaccades depends on the experimental condition and time of occurrence, but it can be very strong.},
language = {en}
}
@article{LaubrockKlieglEngbert2006,
author = {Laubrock, Jochen and Kliegl, Reinhold and Engbert, Ralf},
title = {SWIFT explorations of age differences in eye movements during reading},
issn = {0149-7634},
doi = {10.1016/j.neubiorev.2006.06.013},
year = {2006},
language = {en}
}
@article{LaubrockEngbertRolfsetal.2007,
author = {Laubrock, Jochen and Engbert, Ralf and Rolfs, Martin and Kliegl, Reinhold},
title = {Microsaccades are an index of covert attention : commentary on Horowitz, Fine, Fencsik, Yurgenson and Wolfe},
issn = {0956-7976},
doi = {10.1111/j.1467-9280.2007.01904.x},
year = {2007},
language = {en}
}
@article{LaubrockEngbertKliegl2005,
author = {Laubrock, Jochen and Engbert, Ralf and Kliegl, Reinhold},
title = {Microsaccade dynamics during covert attention},
issn = {0042-6989},
year = {2005},
abstract = {We compared effects of covert spatial-attention shifts induced with exogenous or endogenous cues on microsaccade rate and direction. Separate and dissociated effects were obtained in rate and direction measures. Display changes caused microsaccade rate inhibition, followed by sustained rate enhancement. Effects on microsaccade direction were differentially tied to cue class (exogenous vs. endogenous) and type (neutral vs. directional). For endogenous cues, direction effects were weak and occurred late. Exogenous cues caused a fast direction bias towards the cue (i.e., early automatic triggering of saccade programs), followed by a shift in the opposite direction (i.e, controlled inhibition of cue-directed saccades, leading to a 'leakage' of microsaccades in the opposite direction). (C) 2004 Elsevier Ltd. All rights reserved},
language = {en}
}
@article{LaubrockEngbertKliegl2005,
author = {Laubrock, Jochen and Engbert, Ralf and Kliegl, Reinhold},
title = {Microsaccade rate during (un)ambiguous apparent motion},
issn = {0301-0066},
year = {2005},
language = {en}
}
@article{LaubrockEngbertKliegl2008,
author = {Laubrock, Jochen and Engbert, Ralf and Kliegl, Reinhold},
title = {Fixational eye movements predict the perceived direction of ambiguous apparent motion},
issn = {1534-7362},
doi = {10.1167/8.14.13},
year = {2008},
abstract = {Neuronal activity in area LIP is correlated with the perceived direction of ambiguous apparent motion (Z. M. Williams, J. C. Elfar, E. N. Eskandar, L. J. Toth, \& J. A. Assad, 2003). Here we show that a similar correlation exists for small eye movements made during fixation. A moving dot grid with superimposed fixation point was presented through an aperture. In a motion discrimination task, unambiguous motion was compared with ambiguous motion obtained by shifting the grid by half of the dot distance. In three experiments we show that (a) microsaccadic inhibition, i.e., a drop in microsaccade frequency precedes reports of perceptual flips, (b) microsaccadic inhibition does not accompany simple response changes, and (c) the direction of microsaccades occurring before motion onset biases the subsequent perception of ambiguous motion. We conclude that microsaccades provide a signal on which perceptual judgments rely in the absence of objective disambiguating stimulus information.},
language = {en}
}
@misc{LaubrockEngbertCajar2017,
author = {Laubrock, Jochen and Engbert, Ralf and Cajar, Anke},
title = {Gaze-contingent manipulation of the FVF demonstrates the importance of fixation duration for explaining search behavior},
series = {Behavioral and brain sciences : an international journal of current research and theory with open peer commentary},
volume = {40},
journal = {Behavioral and brain sciences : an international journal of current research and theory with open peer commentary},
publisher = {Cambridge Univ. Press},
address = {New York},
issn = {0140-525X},
doi = {10.1017/S0140525X16000145},
pages = {31 -- 32},
year = {2017},
abstract = {Hulleman \& Olivers' (H\&O's) model introduces variation of the functional visual field (FVF) for explaining visual search behavior. Our research shows how the FVF can be studied using gaze-contingent displays and how FVF variation can be implemented in models of gaze control. Contrary to H\&O, we believe that fixation duration is an important factor when modeling visual search behavior.},
language = {en}
}
@article{LaubrockCajarEngbert2013,
author = {Laubrock, Jochen and Cajar, Anke and Engbert, Ralf},
title = {Control of fixation duration during scene viewing by interaction of foveal and peripheral processing},
series = {Journal of vision},
volume = {13},
journal = {Journal of vision},
number = {12},
publisher = {Association for Research in Vision and Opthalmology},
address = {Rockville},
issn = {1534-7362},
doi = {10.1167/13.12.11},
pages = {20},
year = {2013},
abstract = {Processing in our visual system is functionally segregated, with the fovea specialized in processing fine detail (high spatial frequencies) for object identification, and the periphery in processing coarse information (low frequencies) for spatial orienting and saccade target selection. Here we investigate the consequences of this functional segregation for the control of fixation durations during scene viewing. Using gaze-contingent displays, we applied high-pass or low-pass filters to either the central or the peripheral visual field and compared eye-movement patterns with an unfiltered control condition. In contrast with predictions from functional segregation, fixation durations were unaffected when the critical information for vision was strongly attenuated (foveal low-pass and peripheral high-pass filtering); fixation durations increased, however, when useful information was left mostly intact by the filter (foveal high-pass and peripheral low-pass filtering). These patterns of results are difficult to explain under the assumption that fixation durations are controlled by foveal processing difficulty. As an alternative explanation, we developed the hypothesis that the interaction of foveal and peripheral processing controls fixation duration. To investigate the viability of this explanation, we implemented a computational model with two compartments, approximating spatial aspects of processing by foveal and peripheral activations that change according to a small set of dynamical rules. The model reproduced distributions of fixation durations from all experimental conditions by variation of few parameters that were affected by specific filtering conditions.},
language = {en}
}
@inproceedings{LaubrockCajarEngbert2012,
author = {Laubrock, Jochen and Cajar, Anke and Engbert, Ralf},
title = {Peripheral spatial frequency processing affects timing and metrics of saccades},
series = {Perception},
volume = {41},
booktitle = {Perception},
publisher = {Sage Publ.},
address = {London},
issn = {0301-0066},
pages = {170 -- 170},
year = {2012},
language = {en}
}
@article{LangeStarzynskiEngbert2012,
author = {Lange, Elke B. and Starzynski, Christian and Engbert, Ralf},
title = {Capture of the gaze does not capture the mind},
series = {Attention, perception, \& psychophysics : AP\&P ; a journal of the Psychonomic Society, Inc.},
volume = {74},
journal = {Attention, perception, \& psychophysics : AP\&P ; a journal of the Psychonomic Society, Inc.},
number = {6},
publisher = {Springer},
address = {New York},
issn = {1943-3921},
doi = {10.3758/s13414-012-0318-8},
pages = {1168 -- 1182},
year = {2012},
abstract = {Sudden visual changes attract our gaze, and related eye movement control requires attentional resources. Attention is a limited resource that is also involved in working memory-for instance, memory encoding. As a consequence, theory suggests that gaze capture could impair the buildup of memory respresentations due to an attentional resource bottleneck. Here we developed an experimental design combining a serial memory task (verbal or spatial) and concurrent gaze capture by a distractor (of high or low similarity to the relevant item). The results cannot be explained by a general resource bottleneck. Specifically, we observed that capture by the low-similar distractor resulted in delayed and reduced saccade rates to relevant items in both memory tasks. However, while spatial memory performance decreased, verbal memory remained unaffected. In contrast, the high-similar distractor led to capture and memory loss for both tasks. Our results lend support to the view that gaze capture leads to activation of irrelevant representations in working memory that compete for selection at recall. Activation of irrelevant spatial representations distracts spatial recall, whereas activation of irrelevant verbal features impairs verbal memory performance.},
language = {en}
}
@article{LangeEngbert2013,
author = {Lange, Elke B. and Engbert, Ralf},
title = {Differentiating between verbal and spatial encoding using eye-movement recordings},
series = {The quarterly journal of experimental psychology},
volume = {66},
journal = {The quarterly journal of experimental psychology},
number = {9},
publisher = {Wiley},
address = {Hove},
issn = {1747-0218},
doi = {10.1080/17470218.2013.772214},
pages = {1840 -- 1857},
year = {2013},
abstract = {Visual information processing is guided by an active mechanism generating saccadic eye movements to salient stimuli. Here we investigate the specific contribution of saccades to memory encoding of verbal and spatial properties in a serial recall task. In the first experiment, participants moved their eyes freely without specific instruction. We demonstrate the existence of qualitative differences in eye-movement strategies during verbal and spatial memory encoding. While verbal memory encoding was characterized by shifting the gaze to the to-be-encoded stimuli, saccadic activity was suppressed during spatial encoding. In the second experiment, participants were required to suppress saccades by fixating centrally during encoding or to make precise saccades onto the memory items. Active suppression of saccades had no effect on memory performance, but tracking the upcoming stimuli decreased memory performance dramatically in both tasks, indicating a resource bottleneck between display-controlled saccadic control and memory encoding. We conclude that optimized encoding strategies for verbal and spatial features are underlying memory performance in serial recall, but such strategies work on an involuntary level only and do not support memory encoding when they are explicitly required by the task.},
language = {en}
}
@article{KruegelRothkegelEngbert2020,
author = {Kr{\"u}gel, Andr{\´e} and Rothkegel, Lars and Engbert, Ralf},
title = {No exception from Bayes' rule},
series = {Journal of vision},
volume = {20},
journal = {Journal of vision},
number = {7},
publisher = {ARVO},
address = {Rockville},
issn = {1534-7362},
doi = {10.1167/jov.20.7.15},
pages = {14},
year = {2020},
abstract = {In an influential theoretical model, human sensorimotor control is achieved by a Bayesian decision process, which combines noisy sensory information and learned prior knowledge. A ubiquitous signature of prior knowledge and Bayesian integration in human perception and motor behavior is the frequently observed bias toward an average stimulus magnitude (i.e., a central-tendency bias, range effect, regression-to-the-mean effect). However, in the domain of eye movements, there is a recent controversy about the fundamental existence of a range effect in the saccadic system. Here we argue that the problem of the existence of a range effect is linked to the availability of prior knowledge for saccade control. We present results from two prosaccade experiments that both employ an informative prior structure (i.e., a nonuniform Gaussian distribution of saccade target distances). Our results demonstrate the validity of Bayesian integration in saccade control, which generates a range effect in saccades. According to Bayesian integration principles, the saccadic range effect depends on the availability of prior knowledge and varies in size as a function of the reliability of the prior and the sensory likelihood.},
language = {en}
}
@article{KruegelEngbert2010,
author = {Kr{\"u}gel, Andr{\´e} and Engbert, Ralf},
title = {On the launch-site effect for skipped words during reading},
issn = {0042-6989},
doi = {10.1016/j.visres.2010.05.009},
year = {2010},
abstract = {The launch-site effect, a systematic variation of within-word landing position as a function of launch-site distance, is among the most important oculomotor phenomena in reading. Here we show that the launch-site effect is strongly modulated in word skipping, a finding which is inconsistent with the view that the launch-site effect is caused by a saccadic-range error. We observe that distributions of landing positions in skipping saccades show an increased leftward shift compared to non-skipping saccades at equal launch-site distances. Using an improved algorithm for the estimation of mislocated fixations, we demonstrate the reliability of our results.},
language = {en}
}
@article{KruegelVituEngbert2012,
author = {Kr{\"u}gel, Andre and Vitu, Francoise and Engbert, Ralf},
title = {Fixation positions after skipping saccades - a single space makes a large difference},
series = {Attention, perception, \& psychophysics : AP\&P ; a journal of the Psychonomic Society, Inc.},
volume = {74},
journal = {Attention, perception, \& psychophysics : AP\&P ; a journal of the Psychonomic Society, Inc.},
number = {8},
publisher = {Springer},
address = {New York},
issn = {1943-3921},
doi = {10.3758/s13414-012-0365-1},
pages = {1556 -- 1561},
year = {2012},
abstract = {During reading, saccadic eye movements are generated to shift words into the center of the visual field for lexical processing. Recently, Krugel and Engbert (Vision Research 50:1532-1539, 2010) demonstrated that within-word fixation positions are largely shifted to the left after skipped words. However, explanations of the origin of this effect cannot be drawn from normal reading data alone. Here we show that the large effect of skipped words on the distribution of within-word fixation positions is primarily based on rather subtle differences in the low-level visual information acquired before saccades. Using arrangements of "x" letter strings, we reproduced the effect of skipped character strings in a highly controlled single-saccade task. Our results demonstrate that the effect of skipped words in reading is the signature of a general visuomotor phenomenon. Moreover, our findings extend beyond the scope of the widely accepted range-error model, which posits that within-word fixation positions in reading depend solely on the distances of target words. We expect that our results will provide critical boundary conditions for the development of visuomotor models of saccade planning during reading.},
language = {en}
}
@inproceedings{KruegelEngbert2012,
author = {Kr{\"u}gel, Andre and Engbert, Ralf},
title = {Saccade targeting of spatially extended objects a Bayesian model},
series = {Perception},
volume = {41},
booktitle = {Perception},
publisher = {Sage Publ.},
address = {London},
issn = {0301-0066},
pages = {167 -- 167},
year = {2012},
language = {en}
}
@misc{KruegelEngbert2016,
author = {Kruegel, Andre and Engbert, Ralf},
title = {Statistics of microsaccades indicate early frequency effects during visual word recognition},
series = {Perception},
volume = {45},
journal = {Perception},
publisher = {Sage Publ.},
address = {London},
issn = {0301-0066},
pages = {127 -- 127},
year = {2016},
language = {en}
}
@article{KruegelEngbert2014,
author = {Kruegel, Andre and Engbert, Ralf},
title = {A model of saccadic landing positions in reading under the influence of sensory noise},
series = {Visual cognition},
volume = {22},
journal = {Visual cognition},
number = {3-4},
publisher = {Routledge, Taylor \& Francis Group},
address = {Abingdon},
issn = {1350-6285},
doi = {10.1080/13506285.2014.894166},
pages = {334 -- 353},
year = {2014},
language = {en}
}
@article{KrampeKlieglMayretal.2000,
author = {Krampe, Ralf-Thomas and Kliegl, Reinhold and Mayr, Ulrich and Engbert, Ralf and Vorberg, D.},
title = {The fast and the slow of skilled bimanual rhythm production : parallel versus integrated timing},
year = {2000},
language = {en}
}
@article{KrampeEngbertKliegletal.2000,
author = {Krampe, Ralf-Thomas and Engbert, Ralf and Kliegl, Reinhold and Kurths, J{\"u}rgen},
title = {Koordination und Synchronisation der H{\"a}nde beim rhythmischen Timing},
year = {2000},
language = {de}
}
@article{KrampeEngbertKliegl2002,
author = {Krampe, Ralf-Thomas and Engbert, Ralf and Kliegl, Reinhold},
title = {The effects of expertise and age on rhythm production : adaptations to timing and sequencing constraints},
year = {2002},
language = {en}
}
@article{KrampeEngbertKliegl2001,
author = {Krampe, Ralf-Thomas and Engbert, Ralf and Kliegl, Reinhold},
title = {Age-specific problems in rhythmic timing},
year = {2001},
language = {en}
}
@article{KrampeEngbertKliegl2002,
author = {Krampe, Ralf-Thomas and Engbert, Ralf and Kliegl, Reinhold},
title = {Representational models and nonlinear dynamics : irreconcilable approaches to human movement timing and coordination or two sides of the same coin? : Introduction to the special issue on movement timing and coordination},
year = {2002},
language = {en}
}
@misc{KlieglRolfsLaubrocketal.2009,
author = {Kliegl, Reinhold and Rolfs, Martin and Laubrock, Jochen and Engbert, Ralf},
title = {Microsaccadic Modulation of Response Times in Spatial Attention Tasks},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-57098},
year = {2009},
abstract = {Covert shifts of attention are usually reflected in RT differences between responses to valid and invalid cues in the Posner spatial attention task. Such inferences about covert shifts of attention do not control for microsaccades in the cue target interval. We analyzed the effects of microsaccade orientation on RTs in four conditions, crossing peripheral visual and auditory cues with peripheral visual and auditory discrimination targets. Reaction time was generally faster on trials without microsaccades in the cue-target interval. If microsaccades occurred, the target-location congruency of the last microsaccade in the cuetarget interval interacted in a complex way with cue validity. For valid visual cues, irrespective of whether the discrimination target was visual or auditory, target-congruent microsaccades delayed RT. For invalid cues, target-incongruent microsaccades facilitated RTs for visual target discrimination, but delayed RT for auditory target discrimination. No reliable effects on RT were associated with auditory cues or with the first microsaccade in the cue-target interval. We discuss theoretical implications on the relation about spatial attention and oculomotor processes.},
language = {en}
}
@article{KlieglRolfsLaubrocketal.2009,
author = {Kliegl, Reinhold and Rolfs, Martin and Laubrock, Jochen and Engbert, Ralf},
title = {Microsaccadic modulation of response times in spatial attention tasks},
issn = {0340-0727},
doi = {10.1007/s00426-008-0202-2},
year = {2009},
language = {en}
}
@article{KlieglNuthmannEngbert2006,
author = {Kliegl, Reinhold and Nuthmann, Antje and Engbert, Ralf},
title = {Tracking the mind during reading : the influence of past, present, and future words on fixation durations},
issn = {0096-3445},
doi = {10.1037/0096-3445.135.1.12},
year = {2006},
abstract = {Reading requires the orchestration of visual, attentional, language-related, and oculomotor processing constraints. This study replicates previous effects of frequency, predictability, and length of fixated words on fixation durations in natural reading and demonstrates new effects of these variables related to previous and next words. Results are based on fixation durations recorded from 222 persons, each reading 144 sentences. Such evidence for distributed processing of words across fixation durations challenges psycholinguistic immediacy-of-processing and eye- mind assumptions. Most of the time the mind processes several words in parallel at different perceptual and cognitive levels. Eye movements can help to unravel these processes},
language = {en}
}
@misc{KlieglNuthmannEngbert2006,
author = {Kliegl, Reinhold and Nuthmann, Antje and Engbert, Ralf},
title = {Tracking the Mind During Reading: The Influence of Past, Present, and Future Words on Fixation Durations},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-57225},
year = {2006},
abstract = {Reading requires the orchestration of visual, attentional, language-related, and oculomotor processing constraints. This study replicates previous effects of frequency, predictability, and length of fixated words on fixation durations in natural reading and demonstrates new effects of these variables related to previous and next words. Results are based on fixation durations recorded from 222 persons, each reading 144 sentences. Such evidence for distributed processing of words across fixation durations challenges psycholinguistic immediacy-of-processing and eye-mind assumptions. Most of the time the mind processes several words in parallel at different perceptual and cognitive levels. Eye movements can help to unravel these processes.},
language = {en}
}
@article{KlieglGrabnerRolfsetal.2004,
author = {Kliegl, Reinhold and Grabner, Ellen and Rolfs, Martin and Engbert, Ralf},
title = {Length, frequency, and predictability effects of words on eye movements in reading},
year = {2004},
language = {en}
}
@article{KlieglEngbert2005,
author = {Kliegl, Reinhold and Engbert, Ralf},
title = {Fixation durations before word skipping in reading},
issn = {1069-9384},
year = {2005},
abstract = {We resolve a controversy about reading fixations before word-skipping saccades which were reported as longer or shorter than control fixations in earlier studies. Our statistics are based on resampling of matched sets of fixations before skipped and nonskipped words, drawn from a database of 121,321 single fixations contributed by 230 readers of the Potsdam sentence corpus. Matched fixations originated from single-fixation forward-reading patterns and were equated for their positions within words. Fixations before skipped words were shorter before short or high-frequency words and longer before long or low-frequency words in comparison with control fixations. Reasons for inconsistencies in past research and implications for computational models are discussed},
language = {en}
}
@article{KlieglEngbert2003,
author = {Kliegl, Reinhold and Engbert, Ralf},
title = {SWIFT explorations},
year = {2003},
language = {en}
}
@article{KlieglEngbert2003,
author = {Kliegl, Reinhold and Engbert, Ralf},
title = {How tight is the link between lexical processing and saccade programs?},
year = {2003},
abstract = {We question the assumption of serial attention shifts and the assumption that saccade programs are initiated or canceled only after stage one of word identification. Evidence: (1) Fixation durations prior to skipped words are not consistently higher compared to those prior to non-skipped words. (2) Attentional modulation of microsaccade rate might occur after early visual processing. Saccades are probably triggered by attentional selection},
language = {en}
}
@misc{KlieglEngbert2003,
author = {Kliegl, Reinhold and Engbert, Ralf},
title = {How tight is the link between lexical processing and saccade programs?},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-56919},
year = {2003},
abstract = {We question the assumption of serial attention shifts and the assumption that saccade programs are initiated or canceled only after stage one of word identification. Evidence: (1) Fixation durations prior to skipped words are not consistently higher compared to those prior to nonskipped words. (2) Attentional modulation of microsaccade rate might occur after early visual processing. Saccades are probably triggered by attentional selection.},
language = {en}
}
@article{KleinKruegelRisseetal.2015,
author = {Klein, Angela Ines and Kruegel, Andre and Risse, Sarah and Esser, G{\"u}nter and Engbert, Ralf and Pereira, Vera Wannmacher},
title = {The processing of pronominal anaphora by children that have attention deficit hyperactivity disorder or dyslexia: a study through the analysis of eye movements},
series = {Letras de hoje},
volume = {50},
journal = {Letras de hoje},
number = {1},
publisher = {PUCRS},
address = {Porto Alegre},
issn = {0101-3335},
pages = {40 -- 48},
year = {2015},
abstract = {The aim of this work was to verify the processing of pronominal anaphora by children that have attention deficit hyperactivity disorder or dyslexia. The sample studied consisted of 75 children that speak German, which read two texts of 80 words containing pronominal anaphora. The eye movements of all participants were recorded and, to make sure they were reading with attention, two activities that tested reading comprehension were proposed. Through the analysis of eye movements, specifically the fixations, the data indicate that children with disorders have difficulty to process the pronominal anaphora, especially dyslexic children.},
language = {it}
}
@unpublished{GuastiEngbertKrampeetal.2000,
author = {Guasti, Giovanna and Engbert, Ralf and Krampe, Ralf T. and Kurths, J{\"u}rgen},
title = {Phase transitions, complexity, and stationarity in the production of polyrhythms},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-14933},
year = {2000},
abstract = {Contents: 1 Introduction 2 Experiment 3 Data 4 Symbolic dynamics 4.1 Symbolic dynamics as a tool for data analysis 4.2 2-symbols coding 4.3 3-symbols coding 5 Measures of complexity 5.1 Word statistics 5.2 Shannon entropy 6 Testing for stationarity 6.1 Stationarity 6.2 Time series of cycle durations 6.3 Chi-square test 7 Control parameters in the production of rhythms 8 Analysis of relative phases 9 Discussion 10 Outlook},
language = {en}
}
@article{EngelmannVasishthEngbertetal.2013,
author = {Engelmann, Felix and Vasishth, Shravan and Engbert, Ralf and Kliegl, Reinhold},
title = {A framework for modeling the interaction of syntactic processing and eye movement control},
series = {Topics in cognitive science},
volume = {5},
journal = {Topics in cognitive science},
number = {3},
publisher = {Wiley-Blackwell},
address = {Hoboken},
issn = {1756-8757},
doi = {10.1111/tops.12026},
pages = {452 -- 474},
year = {2013},
abstract = {We explore the interaction between oculomotor control and language comprehension on the sentence level using two well-tested computational accounts of parsing difficulty. Previous work (Boston, Hale, Vasishth, \& Kliegl, 2011) has shown that surprisal (Hale, 2001; Levy, 2008) and cue-based memory retrieval (Lewis \& Vasishth, 2005) are significant and complementary predictors of reading time in an eyetracking corpus. It remains an open question how the sentence processor interacts with oculomotor control. Using a simple linking hypothesis proposed in Reichle, Warren, and McConnell (2009), we integrated both measures with the eye movement model EMMA (Salvucci, 2001) inside the cognitive architecture ACT-R (Anderson et al., 2004). We built a reading model that could initiate short Time Out regressions (Mitchell, Shen, Green, \& Hodgson, 2008) that compensate for slow postlexical processing. This simple interaction enabled the model to predict the re-reading of words based on parsing difficulty. The model was evaluated in different configurations on the prediction of frequency effects on the Potsdam Sentence Corpus. The extension of EMMA with postlexical processing improved its predictions and reproduced re-reading rates and durations with a reasonable fit to the data. This demonstration, based on simple and independently motivated assumptions, serves as a foundational step toward a precise investigation of the interaction between high-level language processing and eye movement control.},
language = {en}
}
@article{EngbertTrukenbrodBarthelmeetal.2015,
author = {Engbert, Ralf and Trukenbrod, Hans Arne and Barthelme, Simon and Wichmann, Felix A.},
title = {Spatial statistics and attentional dynamics in scene viewing},
series = {Journal of vision},
volume = {15},
journal = {Journal of vision},
number = {1},
publisher = {Association for Research in Vision and Opthalmology},
address = {Rockville},
issn = {1534-7362},
doi = {10.1167/15.1.14},
pages = {17},
year = {2015},
abstract = {In humans and in foveated animals visual acuity is highly concentrated at the center of gaze, so that choosing where to look next is an important example of online, rapid decision-making. Computational neuroscientists have developed biologically-inspired models of visual attention, termed saliency maps, which successfully predict where people fixate on average. Using point process theory for spatial statistics, we show that scanpaths contain, however, important statistical structure, such as spatial clustering on top of distributions of gaze positions. Here, we develop a dynamical model of saccadic selection that accurately predicts the distribution of gaze positions as well as spatial clustering along individual scanpaths. Our model relies on activation dynamics via spatially-limited (foveated) access to saliency information, and, second, a leaky memory process controlling the re-inspection of target regions. This theoretical framework models a form of context-dependent decision-making, linking neural dynamics of attention to behavioral gaze data.},
language = {en}
}
@unpublished{EngbertScheffczykKrampeetal.1997,
author = {Engbert, Ralf and Scheffczyk, Christian and Krampe, Ralf-Thomas and Rosenblum, Mikhael and Kurths, J{\"u}rgen and Kliegl, Reinhold},
title = {Tempo-induced transitions in polyrhythmic hand movements},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-14380},
year = {1997},
abstract = {We investigate the cognitive control in polyrhythmic hand movements as a model paradigm for bimanual coordination. Using a symbolic coding of the recorded time series, we demonstrate the existence of qualitative transitions induced by experimental manipulation of the tempo. A nonlinear model with delayed feedback control is proposed, which accounts for these dynamical transitions in terms of bifurcations resulting from variation of the external control parameter. Furthermore, it is shown that transitions can also be observed due to fluctuations in the timing control level. We conclude that the complexity of coordinated bimanual movements results from interactions between nonlinear control mechanisms with delayed feedback and stochastic timing components.},
language = {en}
}
@article{EngbertRabeSchwetlicketal.2022,
author = {Engbert, Ralf and Rabe, Maximilian Michael and Schwetlick, Lisa and Seelig, Stefan A. and Reich, Sebastian and Vasishth, Shravan},
title = {Data assimilation in dynamical cognitive science},
series = {Trends in cognitive sciences},
volume = {26},
journal = {Trends in cognitive sciences},
number = {2},
publisher = {Elsevier},
address = {Amsterdam},
issn = {1364-6613},
doi = {10.1016/j.tics.2021.11.006},
pages = {99 -- 102},
year = {2022},
abstract = {Dynamical models make specific assumptions about cognitive processes that generate human behavior. In data assimilation, these models are tested against timeordered data. Recent progress on Bayesian data assimilation demonstrates that this approach combines the strengths of statistical modeling of individual differences with the those of dynamical cognitive models.},
language = {en}
}
@article{EngbertRabeKliegletal.2021,
author = {Engbert, Ralf and Rabe, Maximilian Michael and Kliegl, Reinhold and Reich, Sebastian},
title = {Sequential data assimilation of the stochastic SEIR epidemic model for regional COVID-19 dynamics},
series = {Bulletin of mathematical biology : official journal of the Society for Mathematical Biology},
volume = {83},
journal = {Bulletin of mathematical biology : official journal of the Society for Mathematical Biology},
number = {1},
publisher = {Springer},
address = {New York},
issn = {0092-8240},
doi = {10.1007/s11538-020-00834-8},
pages = {16},
year = {2021},
abstract = {Newly emerging pandemics like COVID-19 call for predictive models to implement precisely tuned responses to limit their deep impact on society. Standard epidemic models provide a theoretically well-founded dynamical description of disease incidence. For COVID-19 with infectiousness peaking before and at symptom onset, the SEIR model explains the hidden build-up of exposed individuals which creates challenges for containment strategies. However, spatial heterogeneity raises questions about the adequacy of modeling epidemic outbreaks on the level of a whole country. Here, we show that by applying sequential data assimilation to the stochastic SEIR epidemic model, we can capture the dynamic behavior of outbreaks on a regional level. Regional modeling, with relatively low numbers of infected and demographic noise, accounts for both spatial heterogeneity and stochasticity. Based on adapted models, short-term predictions can be achieved. Thus, with the help of these sequential data assimilation methods, more realistic epidemic models are within reach.},
language = {en}
}
@misc{EngbertNuthmannRichteretal.2005,
author = {Engbert, Ralf and Nuthmann, Antje and Richter, Eike M. and Kliegl, Reinhold},
title = {SWIFT: A Dynamical Model of Saccade Generation during Reading},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-57145},
year = {2005},
abstract = {Mathematical models have become an important tool for understanding the control of eye movements during reading. Main goals of the development of the SWIFT model (Engbert, Longtin, \& Kliegl, 2002)were to investigate the possibility of spatially distributed processing and to implement a general mechanism for all types of eye movements we observe in reading experiments. Here, we present an advanced version of SWIFT which integrates properties of the oculomotor system and effects of word recognition to explain many of the experimental phenomena faced in reading research. We propose new procedures for the estimation of model parameters and for the test of the model's performance. A mathematical analysis of the dynamics of the SWIFT model is presented. Finally, within this framework, we present an analysis of the transition from parallel to serial processing.},
language = {en}
}
@article{EngbertNuthmannRichteretal.2005,
author = {Engbert, Ralf and Nuthmann, Antje and Richter, Eike M. and Kliegl, Reinhold},
title = {SWIFT : A dynamical model of saccade generation during reading},
issn = {0033-295X},
year = {2005},
abstract = {Mathematical, models,have become an important tool for understanding the control of eye movements during reading. Main goals of the development of the SWIFT model (R. Engbert, A. Longtin, \& R. Kliegl, 2002) were to investigate the possibility of spatially distributed processing and to implement a general mechanism for all types of eye movements observed in reading experiments. The authors present an advanced version of SWIFT that integrates properties of the oculomotor system and effects of word recognition to explain many of the experimental phenomena faced in reading research. They propose new procedures for the estimation of model parameters and for the test of the model's performance. They also present a mathematical analysis of the dynamics of the SWIFT model. Finally, within this framework, they present an analysis of the transition from parallel to serial processing},
language = {en}
}
@article{EngbertNuthmannKliegl2007,
author = {Engbert, Ralf and Nuthmann, Antje and Kliegl, Reinhold},
title = {An lterative algorithm for the estimation of the distribution of mislocated fixations during reading},
isbn = {978-0-08-044980-7},
year = {2007},
language = {en}
}
@article{EngbertMergenthalerSinnetal.2011,
author = {Engbert, Ralf and Mergenthaler, Konstantin and Sinn, Petra and Pikovskij, Arkadij},
title = {An integrated model of fixational eye movements and microsaccades},
series = {Proceedings of the National Academy of Sciences of the United States of America},
volume = {108},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
number = {39},
publisher = {National Acad. of Sciences},
address = {Washington},
issn = {0027-8424},
doi = {10.1073/pnas.1102730108},
pages = {E765 -- E770},
year = {2011},
abstract = {When we fixate a stationary target, our eyes generate miniature (or fixational) eye movements involuntarily. These fixational eye movements are classified as slow components (physiological drift, tremor) and microsaccades, which represent rapid, small-amplitude movements. Here we propose an integrated mathematical model for the generation of slow fixational eye movements and microsaccades. The model is based on the concept of self-avoiding random walks in a potential, a process driven by a self-generated activation field. The self-avoiding walk generates persistent movements on a short timescale, whereas, on a longer timescale, the potential produces antipersistent motions that keep the eye close to an intended fixation position. We introduce microsaccades as fast movements triggered by critical activation values. As a consequence, both slow movements and microsaccades follow the same law of motion; i.e., movements are driven by the self-generated activation field. Thus, the model contributes a unified explanation of why it has been a long-standing problem to separate slow movements and microsaccades with respect to their motion-generating principles. We conclude that the concept of a self-avoiding random walk captures fundamental properties of fixational eye movements and provides a coherent theoretical framework for two physiologically distinct movement types.},
language = {en}
}
@article{EngbertMergenthaler2005,
author = {Engbert, Ralf and Mergenthaler, Konstantin},
title = {Statistics of fixational eye movements and oculomotor control},
issn = {0301-0066},
year = {2005},
language = {en}
}
@article{EngbertMergenthaler2006,
author = {Engbert, Ralf and Mergenthaler, Konstantin},
title = {Microsaccades are triggered by low retinal image slip},
issn = {0027-8424},
doi = {10.1073/pnas.0509557103},
year = {2006},
abstract = {Even during visual fixation of a stationary target, our eyes perform rather erratic miniature movements, which represent a random walk. These "fixational" eye movements counteract perceptual fading, a consequence of fast adaptation of the retinal receptor systems to constant input. The most important contribution to fixational eye movements is produced by microsaccades; however, a specific function of microsaccades only recently has been found. Here we show that the occurrence of microsaccades is correlated with low retinal image slip approximate to 200 ms before microsaccade onset. This result suggests that microsaccades are triggered dynamically, in contrast to the current view that microsaccades are randomly distributed in time characterized by their rate-of-occurrence of 1 to 2 per second. As a result of the dynamic triggering mechanism, individual microsaccade rate can be predicted by the fractal dimension of trajectories. Finally, we propose a minimal computational model for the dynamic triggering of microsaccades},
language = {en}
}
@article{EngbertLongtinKliegl2002,
author = {Engbert, Ralf and Longtin, Andre and Kliegl, Reinhold},
title = {A dynamical model of saccade generation in reading based on spatially distributed lexical processing},
year = {2002},
language = {en}
}
@article{EngbertKruegel2010,
author = {Engbert, Ralf and Kruegel, Andr{\´e}},
title = {Readers use Bayesian estimation for eye movement control},
issn = {0956-7976},
doi = {10.1177/0956797610362060},
year = {2010},
abstract = {During reading, saccadic landing positions within words show a pronounced peak close to the word center, with an additional systematic error that is modulated by the distance from the launch site and the length of the target word. Here we show that the systematic variation of fixation positions within words, the saccadic range error, can be derived from Bayesian decision theory. We present the first mathematical model for the saccadic range error; this model makes explicit assumptions regarding underlying visual and oculomotor processes. Analyzing a corpus of eye movement recordings, we obtained results that are consistent with the view that readers use Bayesian estimation for saccade planning. Furthermore, we show that alternative models fail to reproduce the experimental data.},
language = {en}
}
@article{EngbertKrampeKliegl2002,
author = {Engbert, Ralf and Krampe, Ralf-Thomas and Kliegl, Reinhold},
title = {Synchronizing movements with the metronome : nonlinear error corrections and unstable periodic orbits},
year = {2002},
language = {en}
}
@article{EngbertKlieglLongtin2004,
author = {Engbert, Ralf and Kliegl, Reinhold and Longtin, Andre},
title = {Complexity of eye movements in reading},
year = {2004},
abstract = {During reading, our eyes perform complicated sequences of fixations on words. Stochastic models of eye movement control suggest that this seemingly erratic behaviour can be attributed to noise in the oculomotor system and random fluctuations in lexical processing. Here, we present a qualitative analysis of a recently published dynamical model [Engbert et al., 2002] and propose that deterministic nonlinear control accounts for much of the observed complexity of eye movement patterns during reading. Based on a symbolic coding technique we analyze robust statistical features of simulated fixation sequences},
language = {en}
}
@article{EngbertKliegl2003,
author = {Engbert, Ralf and Kliegl, Reinhold},
title = {Microsaccades uncover the orientation of covert attention},
year = {2003},
language = {en}
}
@article{EngbertKliegl2003,
author = {Engbert, Ralf and Kliegl, Reinhold},
title = {Noise-enhanced performance in reading},
year = {2003},
language = {en}
}
@article{EngbertKliegl2003,
author = {Engbert, Ralf and Kliegl, Reinhold},
title = {The game of word skipping : who are the competitors?},
year = {2003},
abstract = {Computational models such as E-Z Reader and SWIFT are ideal theoretical tools to test quantitatively our current understanding of eye-movement control in reading. Here we present a mathematical analysis of word skipping in the E-Z Reader model by semianalytic methods, to highlight the differences in current modeling approaches. In E-Z Reader, the word identification system must outperform the oculomotor system to induce word skipping. In SWIFT, there is competition among words to be selected as a saccade target. We conclude that it is the question of competitors in the "game" of word skipping that must be solved in eye movement research},
language = {en}
}