@misc{CajarEngbertLaubrock2022, author = {Cajar, Anke and Engbert, Ralf and Laubrock, Jochen}, title = {Potsdam Eye-Movement Corpus for Scene Memorization and Search With Color and Spatial-Frequency Filtering}, series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, journal = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, issn = {1866-8364}, doi = {10.25932/publishup-56318}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-563184}, pages = {1 -- 7}, year = {2022}, 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} } @misc{ChandraKruegelEngbert2020, author = {Chandra, Johan and Kr{\"u}gel, Andr{\´e} and Engbert, Ralf}, title = {Modulation of oculomotor control during reading of mirrored and inverted texts}, series = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, number = {659}, issn = {1866-8364}, doi = {10.25932/publishup-49487}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-494879}, pages = {17}, year = {2020}, abstract = {The interplay between cognitive and oculomotor processes during reading can be explored when the spatial layout of text deviates from the typical display. In this study, we investigate various eye-movement measures during reading of text with experimentally manipulated layout (word-wise and letter-wise mirrored-reversed text as well as inverted and scrambled text). While typical findings (e.g., longer mean fixation times, shorter mean saccades lengths) in reading manipulated texts compared to normal texts were reported in earlier work, little is known about changes of oculomotor targeting observed in within-word landing positions under the above text layouts. Here we carry out precise analyses of landing positions and find substantial changes in the so-called launch-site effect in addition to the expected overall slow-down of reading performance. Specifically, during reading of our manipulated text conditions with reversed letter order (against overall reading direction), we find a reduced launch-site effect, while in all other manipulated text conditions, we observe an increased launch-site effect. Our results clearly indicate that the oculomotor system is highly adaptive when confronted with unusual reading conditions.}, language = {en} } @misc{BackhausEngbertRothkegeletal.2020, author = {Backhaus, Daniel and Engbert, Ralf and Rothkegel, Lars Oliver Martin and Trukenbrod, Hans Arne}, title = {Task-dependence in scene perception: Head unrestrained viewing using mobile eye-tracking}, series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, journal = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, number = {5}, issn = {1866-8364}, doi = {10.25932/publishup-51912}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-519124}, pages = {23}, year = {2020}, abstract = {Real-world scene perception is typically studied in the laboratory using static picture viewing with restrained head position. Consequently, the transfer of results obtained in this paradigm to real-word scenarios has been questioned. The advancement of mobile eye-trackers and the progress in image processing, however, permit a more natural experimental setup that, at the same time, maintains the high experimental control from the standard laboratory setting. We investigated eye movements while participants were standing in front of a projector screen and explored images under four specific task instructions. Eye movements were recorded with a mobile eye-tracking device and raw gaze data were transformed from head-centered into image-centered coordinates. We observed differences between tasks in temporal and spatial eye-movement parameters and found that the bias to fixate images near the center differed between tasks. Our results demonstrate that current mobile eye-tracking technology and a highly controlled design support the study of fine-scaled task dependencies in an experimental setting that permits more natural viewing behavior than the static picture viewing paradigm.}, 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} } @misc{NuthmannVituEngbertetal.2015, author = {Nuthmann, Antje and Vitu, Fran{\c{c}}oise 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 = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, number = {506}, issn = {1866-8364}, doi = {10.25932/publishup-41163}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-411639}, pages = {27}, year = {2015}, 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} } @misc{KruegelVituEngbert2012, author = {Kr{\"u}gel, Andr{\´e} and Vitu, Fran{\c{c}}oise and Engbert, Ralf}, title = {Fixation positions after skipping saccades}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, number = {856}, issn = {1866-8372}, doi = {10.25932/publishup-43288}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-432887}, 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} } @misc{SinnEngbert2011, author = {Sinn, Petra and Engbert, Ralf}, title = {Saccadic facilitation by modulation of microsaccades in natural backgrounds}, series = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, number = {595}, issn = {1866-8364}, doi = {10.25932/publishup-43181}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-431817}, pages = {7}, 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{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} } @misc{KlieglEngbert2007, author = {Kliegl, Reinhold and Engbert, Ralf}, title = {Conference Abstracts: 14th European Conference on Eye Movements ECEM2007}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-56799}, year = {2007}, language = {de} }