@misc{OngKliegl2008, author = {Ong, James Kwan Yau and Kliegl, Reinhold}, title = {Conditional co-occurrence probability acts like frequency in predicting fixation durations}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-56771}, year = {2008}, abstract = {The predictability of an upcoming word has been found to be a useful predictor in eye movement research, but is expensive to collect and subjective in nature. It would be desirable to have other predictors that are easier to collect and objective in nature if these predictors were capable of capturing the information stored in predictability. This paper contributes to this discussion by testing a possible predictor: conditional co-occurrence probability. This measure is a simple statistical representation of the relatedness of the current word to its context, based only on word co-occurrence patterns in data taken from the Internet. In the regression analyses, conditional co-occurrence probability acts like lexical frequency in predicting fixation durations, and its addition does not greatly improve the model fits. We conclude that readers do not seem to use the information contained within conditional co-occurrence probability during reading for meaning, and that similar simple measures of semantic relatedness are unlikely to be able to replace predictability as a predictor for fixation durations. Keywords: Co-occurrence probability, Cloze predictability, frequency, eye movement, fixation duration.}, language = {en} } @article{OngKliegl2008, author = {Ong, James Kwan Yau and Kliegl, Reinhold}, title = {Conditional co-occurrence probability acts like frequency in predicting fixation durations}, issn = {1995-8692}, year = {2008}, language = {en} } @misc{OlsonKlieglDavidsonetal.1985, author = {Olson, Richard K. and Kliegl, Reinhold and Davidson, Brian J. and Foltz, Gregory}, title = {Individual and developmental differences in reading disability}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-39916}, year = {1985}, abstract = {I. Introduction A. Theoretical Framework and Selection of Tests B. Related Studies of Reading Disability Subtypes C. Overview of Specific Questions and Article Outline II. Selection criteria nd performance on standardized measures III. Group differences between disabled and normal readers A. Phonetic Memory B. Picture-Naming Speed and Automatic Responses to Print C. Phonological and Orthographic Skill D. Easy Regular and Exception Word Reading E. Difficult Regular and Exception Words IV. Individual diferences in reading disability A. Phonological Skill, Orthographic Skill, and the Regularity Effect B. Phonological Skill, Orthographic Skill, and Spelling Errors V. Eye movement reading style A. The "Plodder-Explorer" Dimension of Eye Movement Reading Style B. Eye Movements, Coding Skills, and Spelling Ratings C. Verbal Intelligence and the Plodder-Explorer Dimension D. Eye Movements in a Nonreading Task and the "Visual-Spatial" Subtype VI. Distribution and etiology of reading disabilities A. Distribution Issues B. Etiology of Reading Disabilities VII. Summary and new directions in research}, language = {en} } @misc{OlsonKlieglDavidson1983, author = {Olson, Richard K. and Kliegl, Reinhold and Davidson, Brian J.}, title = {Dyslexic and normal readers' eye movements}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-41071}, year = {1983}, abstract = {Dyslexic and normal readers' eye movements were compared while tracking a moving fixation point and in reading. Contrary to previous reports, the dyslexic and normal readers did not differ in their number of saccades, percentage of regressions, or stability of fixations in the tracking task. Thus, defective oculomotor control was not associated with or a causal factor in dyslexia, and the dyslexics' abnormal eye movements in reading must be related to differences in higher cognitive processes. However, individual differences in oculmotor efficiency, independent of reading ability, were found within both the dyslexic and normal groups, and these differences were correlated in reading and tracking tasks.}, language = {en} } @misc{OlsonKlieglDavidson1983, author = {Olson, Richard K. and Kliegl, Reinhold and Davidson, Brian J.}, title = {Eye Movements in Reading Disability}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-39880}, year = {1983}, abstract = {Contents: I. Introduction II. Word Coding Processes A. Word Recognition B. Orthographic Coding C. Phonological Coding III. Eye Monitor and Reading Task IV. Group Differences V. Dimensions of Individual Differences A. Regressive Fixation Index and Word Recognition B. Regressive Fixation Index and IQ C. Regressive Fixation Index and Saccade Length D. Regressive Fixation Index and Relative Phonological Skill VI. Multiple Regression Models of Individual Differences A. Disabled Readers in the Aloud Condition B. Disabled Readers in the Silent Condition C. Normal Readers in Silent and Aloud Conditions VII. Conclusions}, language = {en} } @misc{OlsonDavidsonKliegletal.1984, author = {Olson, Richard K. and Davidson, Brian J. and Kliegl, Reinhold and Davies, Susan E.}, title = {Development of phonetic memory in disabled and normal readers}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-16888}, year = {1984}, abstract = {The development of phonetic codes in memory of 141 pairs of normal and disabled readers from 7.8 to 16.8 years of age was tested with a task adapted from L. S. Mark, D. Shankweiler, I. Y. Liberman, and C. A. Fowler (Memory \& Cognition, 1977, 5, 623-629) that measured false-positive errors in recognition memory for foil words which rhymed with words in the memory list versus foil words that did not rhyme. Our younger subjects replicated Mark et al., showing a larger difference between rhyming and nonrhyming false-positive errors for the normal readers. The older disabled readers' phonetic effect was comparable to that of the younger normal readers, suggesting a developmental lag in their use of phonetic coding in memory. Surprisingly, the normal readers' phonetic effect declined with age in the recognition task, but they maintained a significant advantage across age in the auditory WISC-R digit span recall test, and a test of phonological nonword decoding. The normals' decline with age in rhyming confusion may be due to an increase in the precision of their phonetic codes.}, language = {en} } @article{OhlWohltatKliegletal.2016, author = {Ohl, Sven and Wohltat, Christian and Kliegl, Reinhold and Pollatos, Olga and Engbert, Ralf}, title = {Microsaccades Are Coupled to Heartbeat}, series = {The journal of neuroscience}, volume = {36}, journal = {The journal of neuroscience}, publisher = {Society for Neuroscience}, address = {Washington}, issn = {0270-6474}, doi = {10.1523/JNEUROSCI.2211-15.2016}, pages = {1237 -- 1241}, year = {2016}, abstract = {During visual fixation, the eye generates microsaccades and slower components of fixational eye movements that are part of the visual processing strategy in humans. Here, we show that ongoing heartbeat is coupled to temporal rate variations in the generation of microsaccades. Using coregistration of eye recording and ECG in humans, we tested the hypothesis that microsaccade onsets are coupled to the relative phase of the R-R intervals in heartbeats. We observed significantly more microsaccades during the early phase after the R peak in the ECG. This form of coupling between heartbeat and eye movements was substantiated by the additional finding of a coupling between heart phase and motion activity in slow fixational eye movements; i.e., retinal image slip caused by physiological drift. Our findings therefore demonstrate a coupling of the oculomotor system and ongoing heartbeat, which provides further evidence for bodily influences on visuomotor functioning.}, language = {en} } @article{OhlKliegl2016, author = {Ohl, Sven and Kliegl, Reinhold}, title = {Revealing the time course of signals influencing the generation of}, series = {Vision research : an international journal for functional aspects of vision.}, volume = {124}, journal = {Vision research : an international journal for functional aspects of vision.}, publisher = {Elsevier}, address = {Oxford}, issn = {0042-6989}, doi = {10.1016/j.visres.2016.06.007}, pages = {52 -- 58}, year = {2016}, abstract = {Saccadic eye movements are frequently followed by smaller secondary saccades which are generally assumed to correct for the error in primary saccade landing position. However, secondary saccades can also occur after accurate primary saccades and they are often as small as microsaccades, therefore raising the need to further scrutinize the processes involved in secondary saccade generation. Following up a previous study, we analyzed secondary saccades using rate analysis which allows us to quantify experimental effects as shifts in distributions, therefore going beyond comparisons of mean differences. We use Aalen's additive hazards model to delineate the time course of key influences on the secondary saccade rate. In addition to the established effect of primary saccade error, we observed a time-varying influence of under- vs. overshooting - with a higher risk of generating secondary saccades following undershoots. Moreover, increasing target eccentricity influenced the programming of secondary saccades, therefore demonstrating that error-unrelated variables co-determine secondary saccade programs. Our results provide new insights into the generative mechanisms of small saccades during postsaccadic fixation that need to be accounted for by secondary saccade models.}, language = {en} } @article{OhlBrandtKliegl2013, author = {Ohl, Sven and Brandt, Stephan A. and Kliegl, Reinhold}, title = {The generation of secondary saccades without postsaccadic visual feedback}, series = {Journal of vision}, volume = {13}, journal = {Journal of vision}, number = {5}, publisher = {Association for Research in Vision and Opthalmology}, address = {Rockville}, issn = {1534-7362}, doi = {10.1167/13.5.11}, pages = {23}, year = {2013}, abstract = {Primary saccades are often followed by small secondary saccades, which are generally thought to reduce the distance between the saccade endpoint and target location. Accumulated evidence demonstrates that secondary saccades are subject to various influences, among which retinal feedback during postsaccadic fixation constitutes only one important signal. Recently, we reported that target eccentricity and an orientation bias influence the generation of secondary saccades. In the present study, we examine secondary saccades in the absence of postsaccadic visual feedback. Although extraretinal signals (e.g., efference copy) have received widespread attention in eye-movement studies, it is still unclear whether an extraretinal error signal contributes to the programming of secondary saccades. We have observed that secondary saccade latency and amplitude depend on primary saccade error despite the absence of postsaccadic visual feedback. Strong evidence for an extraretinal error signal influencing secondary saccade programming is given by the observation that secondary saccades are more likely to be oriented in a direction opposite to the primary saccade as primary saccade error shifts from target undershoot to overshoot. We further show how the functional relationship between primary saccade landing position and secondary saccade characteristics varies as a function of target eccentricity. We propose that initial target eccentricity and an extraretinal error signal codetermine the postsaccadic activity distribution in the saccadic motor map when no visual feedback is available.}, language = {en} } @article{OhlBrandtKliegl2011, author = {Ohl, Sven and Brandt, Stephan A. and Kliegl, Reinhold}, title = {Secondary (micro-)saccades the influence of primary saccade end point and target eccentricity on the process of postsaccadic fixation}, series = {Vision research : an international journal for functional aspects of vision.}, volume = {51}, journal = {Vision research : an international journal for functional aspects of vision.}, number = {23-24}, publisher = {Elsevier}, address = {Oxford}, issn = {0042-6989}, doi = {10.1016/j.visres.2011.09.005}, pages = {2340 -- 2347}, year = {2011}, abstract = {We examine how the size of saccadic under-/overshoot and target eccentricity influence the latency, amplitude and orientation of secondary (micro-)saccades. In our experiment, a target appeared at an eccentricity of either 6 degrees or 14 degrees of visual angle. Subjects were instructed to direct their gaze as quickly as possible to the target and hold fixation at the new location until the end of the trial. Typically, increasing saccadic error is associated with faster and larger secondary saccades. We show that secondary saccades at distant in contrast to close targets have in a specific error range a shorter latency, larger amplitude, and follow more often the direction of the primary saccade. Finally, we demonstrate that an undershooting primary saccade is followed almost exclusively by secondary saccades into the same direction while overshooting primary saccades are followed by secondary saccades into both directions. This supports the notion that under- and overshooting imply different consequences for postsaccadic oculomotor processing. Results are discussed using a model, introduced by Rolfs, Kliegl, and Engbert (2008), to account for the generation of microsaccades. We argue that the dynamic interplay of target eccentricity and the magnitude of the saccadic under-/overshoot can be explained by a different strength of activation in the two hemispheres of the saccadic motor map in this model.}, language = {en} }