TY  - GEN
A1  - Chandra, Johan
A1  - Krügel, André
A1  - Engbert, Ralf
T1  - Modulation of oculomotor control during reading of mirrored and inverted texts
T2  - Postprints der Universität Potsdam : Humanwissenschaftliche Reihe
N2  - 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.
T3  - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 659 
KW  - human behaviour
KW  - psychology
KW  - eye-movement control
KW  - e-z reader
KW  - ideal-observer model
KW  - fixation locations
KW  - landing positions
KW  - saccade generation
KW  - cognitive-control
KW  - dynamical model
KW  - decision-theory
KW  - attention
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-494879
SN  - 1866-8364
IS  - 659
ER  - 
TY  - GEN
A1  - Nuthmann, Antje
A1  - Vitu, Françoise
A1  - Engbert, Ralf
A1  - Kliegl, Reinhold
T1  - No evidence for a saccadic range effect for visually guided and memory-guided saccades in simple saccade-targeting tasks
T2  - Postprints der Universität Potsdam : Humanwissenschaftliche Reihe
N2  - 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.
T3  - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 506 
KW  - eye-movement control
KW  - scleral search coils
KW  - Z-reader model
KW  - psychophysics toolbox
KW  - oculomotor control
KW  - video-oculography
KW  - accuracy
KW  - microsaccades
KW  - eccentricity
KW  - tracking
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-411639
SN  - 1866-8364
IS  - 506
ER  -