Phenomenology of Transitions in Binocular Rivalry

Investigating the perceptual variety of transitions in binocular rivalry

Context

Part of my PhD research in the Visual Neuroscience Lab, University of Graz, Austria

Supervisor: Assoc. Prof. Dr. Natalia Zaretskaya
Period: 09/2020 – Present

Binocular rivalry occurs when two eyes are presented with two different images that cannot be fused into each other as a uniform perception. As a result, the subject has a perception alternating between the dominant image of either of the presentations with a transition phase.

Research Questions

How many different appearances can observers perceive during perceptual transitions in binocular rivalry?
Are the transition appearances consistent over time?
Does the observers’ age affect the transition appearance?
How does the contrast of stimuli influence the transition apperance?
How does the locus of attention affect the transition appearance?

Objective: Understand the dynamics of conscious visual perception using behavioral data.

Experiment 1: Qualitative descriptions of transitions & Age effect

I presented different visual stimuli to the participants. After the stimulus presentation, they described what they perceived during the perceptual transitions verbally and with a simple sketch. Then, my colleagues and I categorized these transition descriptions.

125 participants (18-65 years)

Binocular rivalry (BR) paradigm

Stimulus types:

gratings with orientation of ± 45 degree
images of house and face
moving dots
grating and image
moving dots and image
moving dots and grating

Task: Press a button to report exclusive percept

Experiment 2: Contrast & Attention effect on transition types

Again, the participant were presented by different visual stimuli. They pressed one of four buttons to report which type of transition they were perceiving. I manipulated the contrast of stimuli and attention of the participant during the experiments. Then, I analyzed the effect of my manipulations on the duration and relative frequency of transition types.

79 participants (18-40 years)

Binocular rivalry (BR) paradigm

Stimulus types:

gratings with orientation of ± 45 degree
images of house and face
moving dots

Task: Press a button to report transition type

Methods & Results

Analysis of behavioral data
→ Preprocessing (cleaning irrelavant keys, removing outliers)
→ Linear mixed model (LMM) for BR parameters
→ Cochran's Q test (categorical ANOVA)
→ Visualization of transition reports

Result: frequency map of transition types

Findings:

20 categories of transition appearance
Effect of stimulus type
Consistency in time
Individual difference
Decline of probability with age
Similar quantitative but different qualitative effect of contrast & attention

Tools & Libraries

R: stats, nlme, lme4, emmeans, ggplot2
Psychtoolbox for stimulus presentation and behavioral recording
R Markdown for reproducible analysis

Outcome & Impact

This research project focuses on the phenomenology and dynamics of conscious visual perception. Through a series of psychophysical studies on binocular rivalry, I explored how perceptual transitions emerge, how they are experienced subjectively, and how they are influenced by factors such as attention and contrast.

This line of work contributes to a growing shift in consciousness research—from merely correlating perception with physical stimuli toward examining how experience itself unfolds over time. By quantifying subtle aspects of subjective transitions, my studies help to characterize conscious perception as a continuous, temporally structured process rather than a series of discrete states.

Together, my publication in Neuroscience of Consciousness and my preprint in PsyArXiv highlight the value of combining rigorous behavioral experimentation with careful phenomenological analysis. They advance an empirical approach to consciousness that respects both the measurable and the experiential dimensions of perception.

Publications

PsyArXiv

Yilmaz, C., Maitz, K., Gerschütz, M., Grassegger, W., Ischebeck, A., Bartels, A., and Zaretskaya, N. (2025). Differential effects of attention and contrast on transition appearance during binocular rivalry. PsyArXiv preprint. DOI: 10.31234/osf.io/64ja9_v2

Neuroscience of Consciousness

Yilmaz, C., Pabel, L., Kerschenbauer, E., Ischebeck, A. Sipatchin, A., Bartels, A. and Zaretskaya, N. (2025). The complexity of human subjective experience during binocular rivalry. Neuroscience of Consciousness. DOI: 10.1093/nc/niaf004

Public talk

3 Minute Thesis Competition, 15.03.2024, Graz, Austria. Video

Conference talks

53^rd DGPs Congress/15^th ÖGP Conference, 16.09.2024, Vienna, Austria. https://dgps2024.univie.ac.at/home-news/

Trieste Symposium on Perception and Cognition, 27.10.2023, Trieste, Italy. https://sites.units.it//bernardis/symposium2023.html

Poster presentation

European Conference on Visual Perception (ECVP), 30.08.2023, Paphos, Cyprus. Perception

Reproducible pipeline

Fully documented analysis notebooks available on GitHub & OSF

Yilmaz C, and Zaretskaya N. Top-down and bottom-up effects on the subjective experience during binocular rivalry [Dataset]. OSF, 2024. DOI: 10.17605/OSF.IO/FQYXB

Yilmaz C, and Zaretskaya N. The Complexity of Subjective Experience during Binocular Rivalry [Dataset]. OSF, 2024. DOI: 10.17605/OSF.IO/N6DQF

Keywords: cognitive neuroscience, visual perception, binocular rivalry, psychophysics, data science

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