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  - 
TY  - GEN
A1  - Sinn, Petra
A1  - Engbert, Ralf
T1  - Saccadic facilitation by modulation of microsaccades in natural backgrounds
T2  - Postprints der Universität Potsdam : Humanwissenschaftliche Reihe
N2  - 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.
T3  - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 595 
KW  - eye movements
KW  - microsaccade
KW  - saccade latency
KW  - background texture
KW  - saccadic facilitation effect
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-431817
SN  - 1866-8364
IS  - 595
ER  -