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
2025
Alexander Pastukhov, Paula Finkenauer, Leonie Littek, Lea Voss & Claus-Christian Carbon (2025) “Is average dominance phase duration a reliable measure of multistable stimuli dynamics?”Vision Sciences Society Annual Meeting
Abstrakt
When participants view stimuli compatible with multiple perceptual interpretations, their perception continuously switches. Multistable perception is often characterized by an average dominance phase duration, particularly, for studies that compare perception of different groups (patients versus healthy controls, old versus young adults, etc.). Here, we asked a question of how reliable this measure is and how variable it is across sessions compared to within session. We tested this by recruiting 31 participants over 3-5 days reporting on five bistable stimuli (2 versions of kinetic-depth effect that were identical in appearance but differed in rotation axis, Necker cube, moving plaid, and auditory streaming), three-minute blocks, twice per session in random order. The design means that for a given stimulus we can pick a pair of sessions, each two blocks long, and make a direct comparison for statistics of our choice within session (consistency of first and second block within each session A and B) versus between (consistency of first blocks between sessions A and B and same for second blocks). Using this approach, we compared block pairs within and between sessions based on average phase duration and state-dominance index using correlation, average phase differences, variance, and consistency in participant and stimuli order measures. First, we found no systematic changes over sessions. Second, we found that for most statistics variance between sessions was comparable to variance within session, so that reliability is not compromised by measuring over multiple days. Third, critically, variability of average dominance phase duration was so great even within session that it did not allow to reliably differentiate between participants or stimuli (within participant). Taken together, our results argue for caution when using average dominance phase duration as a measure of difference between participants.Alexander Pastukhov, Svenja Dorothee Kühner, Lea Jana Kolbe, Lisa Marlen Hahn & Claus-Christian Carbon (2025) “Not Just Where You Land, But How You Get There: Transition Plausibility in Multistable Perception”European Conference on Visual Perception
Abstrakt
Multistable stimuli allow for several equally plausible perceptual interpretations, leading to spontaneous perceptual alternations despite constant sensory input. While often bistable, some visual displays can support three or four interpretations. In such cases, perceptual dominance may depend not only on the strength of a state but also on the plausibility of switching to it. We investigated this using a quadro-stable kinetic-depth effect—an ambiguously rotating cylinder with one half colored yellow and the other white. It could be seen as either a single rotating cylinder or two half-cylinders rotating in opposite directions (participants reported the rotation direction of the yellow half). In Experiment 1, participants viewed the stimulus continuously for three minutes. All four percepts were equally dominant at the group level. To analyze transition probabilities between perceptual states, we fitted four Bayesian models: (1) equal transitions, (2) symmetrical pair-based transitions, (3) symmetric plausibility but probability computed relative to other transitions, and (4) unique transition probabilities for each pair and direction. Model comparison using information criteria favored the third model, suggesting that while some transitions are more plausible, the actual transition depends on the set of available states and plausibility of transitions to them. In Experiment 2, we presented the stimulus intermittently with blank intervals of 50 ms, 0.5 s, or 1 s, known to evoke different aftereffects. For brief interruptions, the same percept usually resumed. For longer gaps, whole-cylinder percepts tended to persist, but half-cylinder percepts often re-emerged as whole-cylinder percepts with the same rotation direction. This suggests that after a 1 s break, visual memory retains motion direction but may not encode the specific configuration. In sum, truly multistable displays reveal how perceptual decisions depend not just on possible outcomes but also on the structure and plausibility of transitions between states.Lotta Straube, Alexander Pastukhov, Anna Heuschkel, Lisa-Alexandra Gromer & Claus-Christian Carbon (2025) “Is There a Circular Design Aesthetic? Insights from the Textile Industry”Visual Science of Art Conference
Abstrakt
Linear product design focuses on a single-use lifecycle, where products are created, used, and then discarded as waste. In contrast, circular product design leverages systems that emphasize resource efficiency, reuse, recycling, and the regeneration of materials. Given its linear and ecologically harmful practices, the fashion industry urgently needs transformation and adopting more circular design approaches. One essential facet in consumers’ decisions in textiles is aesthetics and so it is critical whether industries can provide a kind of “circular design aesthetic” which is unique and appealing. The present research explores this by analysing diverse case studies within the textile industry, which document implementations of circular design approaches, including material selection, production processes, designing for prolonged use, and end-of-life strategies. Alongside these industry examples, an empirical consumer study focusing on denim jeans provides insights into how these design principles are perceived by consumers. Ultimately, this knowledge will be instrumental in guiding designers and industries toward creating products that are circular in practice and resonate with consumers as sustainable and aesthetically pleasing.Lotta Straube, Alexander Pastukhov, Lisa-Alexandra Gromer, Anna Heuschkel & Claus-Christian Carbon (2025) “Sustainable Product and Material Perception: A Multisensory Exploration of Denim Jeans”European Conference on Visual Perception
Abstrakt
With increasing global resource scarcity problems, investing in more sustainable material options in consumer goods is essential. To enable this shift, a better understanding of sustainable material perception and aesthetics is first required, given the pivotal role of consumer acceptance. In this study, participants qualitatively described 10 pairs of denim jeans of the same brand (3 of which were responsibly designed) and then physically placed them on an experiment grid to rate their characteristics in terms of six categories (timelessness, sustainability, recyclability, complexity in production, price, and quality). This was done before (T1) and after (T2) an educational intervention about sustainable design practices. During their exploration of the fashion product and verbal description, many participants defaulted to describing the material properties of the shell fabric first (in terms of weight or hand feel), highlighting the central role that material haptics play in product evaluation. From the quantitative data, we concluded that participants did not intuitively recognize responsible design on their own, nor did this change through the education intervention. Visually, products in solid/uni-color materials were generally seen as more sustainable, indicating a wrong heuristic in judging products that even outweighed the explicit information about responsible design that participants received during the intervention phase. We conclude that the multisensory exploration of consumer goods, such as denim jeans, is essential for thorough product and material evaluation.2024
Lena Schädlich, Alicia Weithase, Alexander Pastukhov & 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 Pastukhov (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 Pastukhov & Claus-Christian Carbon (2019) “Perceptual dominance in face rivalry is driven by low-level properties”European Conference on Visual Perception