Weiter gehen
Die Idee des EMPRA ist es, Studenten ein realistisches Forschungsprojekt durchführen zu lassen. Und manchmal ist die Qualität der Arbeit so hoch, dass sie die Aufmerksamkeit der Forschungsgemeinschaft verdient. Hier sind EMPRA-Projekte aus den vergangenen Jahren, die in einer begutachteten Zeitschrift oder auf einer internationalen wissenschaftlichen Konferenz veröffentlicht wurden. Nachfolgend sind die studentischen Autoren fett markiert.
Publikationen in begutachteten Fachzeitschriften
2019
Alexander Pastukhov, Philipp Kastrup, Isabel Friederike Abs & Christian-Claus Carbon (2019) “Switch rates for orthogonally-oriented kinetic-depth displays are correlated across observers”Journal of Vision, 19(6), 1, 1-13. doi: 10.1167/19.6.1
Abstrakt
When continuously viewing multistable displays, which are compatible with several comparably likely interpretations, perception perpetually switches between available alternatives. Prior studies typically report the lack of consistent individual switch rates across different displays. However, this comparison is based on an assumption that neural representations of physically identical displays are consistent across observers. Yet, given how different individuals are already at the level of the retina, it is likely that the difference in other relevant factors might mask the correlation. To address this issue, we compared switch rates in two kinetic-depth displays (KDE) that rotated around orthogonal axes (458 counterclockwise vs. 458 clockwise relative to the vertical). This ensured that dynamics of multistable perception was based on highly similar, but different and independent neural representations. We also included a Necker cube (NC) display as a control. We report that switch rates were correlated between two kinetic-depth effect displays, but not between either of the KDE and NC displays. This demonstrates that the usual lack of correlation may not be evidence for the lack of a shared pacesetter mechanism of multistable perception, but reflect other factors, such as differently modulated inputs to competing representations. In addition, we asked participants to speed-up or slow-down perceptual alternations and found that only the former ability was correlated across different displays. This indicates that these two types of volitional control may differ in their use of attentional resources.Konferenzbeiträge
2024
Lena Schädlich, Alicia Weithase, Alexander & Claus-Christian Carbon (2024) “Attention works as a filter for prior perceptual decision in serial dependence”European Conference on Visual Perception
Abstrakt
Our perception reflects current sensory evidence but also the history of our previous perceptual decisions. This phenomenon is called serial dependence and is based on the assumption that the world around us is sufficiently stable and a recently made perceptual decision can be used as a supplementary source of information to reduce the uncertainty. In the case of the numerosity judgments, this means that responses for the same stimulus will be higher if it is a part of a descending sequence, as the preceding value is always larger biasing perception upwards, than for an ascending sequence. We tested this using a numerosity judgment task where participants had to estimate the numerosity of briefly presented dots either in full or divided attention conditions. We observed a strong serial dependence both in single and dual tasks. To quantify the effect of prior perception and attention, we used a modified Bayesian integration model that assumed (1) a non-monotonic relationship between numerosity and uncertainty, (2) a Gaussian distance measure between numerosity levels with a scale parameter controlling the relevance of prior decision for the current trial, i.e., smaller scale values mean that only nearby numerosity values are included into the decision, whereas large scale values mean lack of selectivity as any prior numerosity is included. We report that (1) overall uncertainty was the same for both attention conditions, (2) the weight of prior evidence was higher during poor attention blocks, (3) high selectivity (small values of scale parameter) during full attention but virtually no selectivity of prior evidence during poor attention. To summarize, consistent with the idea of attention as a filter, we found that although the prior perceptual decision was used with both full and poor attention, in the latter case it was used indiscriminately, irrespective of its relevance to the current judgment.2019
Lisa Koßmann, Claus-Christian Carbon & Alexander (2019) “Perceptual dominance in face rivalry is driven by low-level properties”European Conference on Visual Perception
Abstrakt
Two superimposed semi-transparent orthogonally-oriented faces produce perceptual rivalry with one face being clearly perceived at a time and perception continuously switching between them. We investigated whether perceptual dominance of an individual face is determined by high-level properties, such as gender, age, or emotion, or low-level properties. To this end, we used twenty female and twenty male faces, aged 20 to 25, from the Chicago Face Database. They were randomly paired using a round-robin tournament schedule (eight blocks, twenty trials each). Participants viewed a face pair and continuously indicated which face they currently perceive via key presses. We computed two measures of face dominance, (i) as a proportion of trials in which it was the first face perceived at onset and (ii) as a proportion of time it was dominant throughout the trial. An exploratory data analysis using linear mixed models showed no systematic relationship between either of the two measures and high-level face descriptors, such as gender, age, or emotions (see https://osf.io/q2fjd). We conclude that in face rivalry perceptual dominance is determined primarily by low-level features such as the size or relative width of the face, or salient local features such as birthmarks.Malin Styrnal, Katharina Walther, Alexander & Claus-Christian Carbon (2019) “Perceptual dominance in face rivalry is driven by low-level properties”European Conference on Visual Perception