Experimental investigation and modeling of factors influencing binocular luster

• Applicant: Dr. Gunnar Wendt
• Subject Area: General, Cognitive and Mathematical Psychology
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 519638685

The purpose of the proposed research project is to further investigate the phenomenon of binocular luster. Research on this phenomenon has experienced a significant boost in the past 20 years after a simple, low-level neural conflict mechanism was proposed as an explanation for the appearance of binocular luster. Our own preliminary work supports this approach. For example, empirical luster judgments measured in a series of psychophysical experiments in a variety of different dichoptic stimulus patterns could be predicted very accurately with a simple physiologically motivated model (interocular conflict model). The properties of the model are consistent with some key assumptions and findings from putatively related areas, such as binocular contrast processing and stereopsis. The study of binocular luster therefore promises to provide a better understanding of fundamental processing principles that also underlie other binocular phenomena.From the preliminary work on binocular luster, further questions have arisen that will be investigated in the proposed research project. The following research goals will be pursued in four subprojects:(1) The interocular conflict model computes a conflict measure that correlates with perceived luster strength. However, the current version of the model does not account for all factors that have a potential influence on the calculation of the conflict measure. For example, the model predicts a dependence of the magnitude of perceived luster on the size or shape of the target area in the stimulus pattern. The goal of Subproject 1 is therefore to examine to what extent perceived luster actually depends on the spatial properties of the target area and how such a dependence can be accounted for in the model.(2) In its present form, the model is based on data collected with dichoptic stimulus patterns between whose monocular half-images there was a difference in luminance contrast. However, the phenomenon of binocular luster can also be generated with color stimuli whose half-images have a purely chromatic difference. The aim of Subproject 2 is to test whether such lustrous impressions generated by color stimuli can be predicted with a similar model based on simple neural mechanisms of color processing.(3) In Subproject 3, it will be tested to what extent the model (in an appropriately adapted form) can also be applied to monocular luster phenomena, such as the monocular luster from flicker or the "scintillating luster" phenomenon. The main question here is whether analogous neuronal structures exist for the monocular luster phenomena or whether they are based on completely different mechanisms.(4) In Subproject 4, we will also test to what extent luster threshold measurements depend on the psychophysical method used and what is the quantitative relationship between further perceptual impressions generated by between-eye differences in luminance contrast.

• DFG Programme: Research Grants