@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{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{YanKlieglRichteretal.2010, author = {Yan, Ming and Kliegl, Reinhold and Richter, Eike M. and Nuthmann, Antje and Shu, Hua}, title = {Flexible saccade-target selection in Chinese reading}, issn = {1747-0218}, doi = {10.1080/17470210903114858}, year = {2010}, abstract = {As Chinese is written without orthographical word boundaries (i.e., spaces), it is unclear whether saccade targets are selected on the basis of characters or words and whether saccades are aimed at the beginning or the centre of words. Here, we report an experiment where 30 Chinese readers read 150 sentences while their eye movements were monitored. They exhibited a strong tendency to fixate at the word centre in single-fixation cases and at the word beginning in multiple-fixation cases. Different from spaced alphabetic script, initial fixations falling at the end of words were no more likely to be followed by a refixation than initial fixations at word centre. Further, single fixations were shorter than first fixations in two-fixation cases, which is opposite to what is found in Roman script. We propose that Chinese readers dynamically select the beginning or centre of words as saccade targets depending on failure or success with segmentation of parafoveal word boundaries.}, 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{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{NuthmannKliegl2009, author = {Nuthmann, Antje and Kliegl, Reinhold}, title = {An examination of binocular reading fixations based on sentence corpus data}, issn = {1534-7362}, doi = {10.1167/9.5.31}, year = {2009}, abstract = {Binocular eye movements of normal adult readers were examined as they read single sentences. Analyses of horizontal and vertical fixation disparities indicated that the most prevalent type of disparate fixation is crossed (i.e., the left eye is located further to the right than the right eye) while the left eye frequently fixates somewhat above the right eye. The Gaussian distribution of the binocular fixation point peaked 2.6 cm in front of the plane of text, reflecting the prevalence of horizontally crossed fixations. Fixation disparity accumulates during the course of successive saccades and fixations within a line of text, but only to an extent that does not compromise single binocular vision. In reading, the version and vergence system interact in a way that is qualitatively similar to what has been observed in simple nonreading tasks. Finally, results presented here render it unlikely that vergence movements in reading aim at realigning the eyes at a given saccade target word.}, language = {en} } @article{NuthmannKliegl2009, author = {Nuthmann, Antje and Kliegl, Reinhold}, title = {Preferred viewing locations : a validation}, issn = {0301-0066}, year = {2009}, 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{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{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{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} } @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{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{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} }