Which colour won for a moment? Red, mixed or blue.
One round, about ten seconds
World 5 of 5
Binocular rivalry test: Perception experiment
No shift —– Strong shift
Not a questionnaire: you imagine a colour, then glance at a pattern. Does your imagination tip what your eyes see?
26 rounds
about 15 min
Red-cyan glasses
What you need
Red-cyan 3D glasses. Simple paper ones are enough. Without glasses, the cross-eyed technique works too, but it takes practice.
Sound on: the tone tells you when to open your eyes.
A dim, quiet room and about 15 minutes.
Why glasses?
Each eye has to see its own pattern: the red lens lets one eye see only the red stripes, the cyan lens lets the other eye see only the cyan stripes. Your brain then flips between the two, and that is where imagining a colour can tip the balance. Without glasses both eyes see the same mixed pattern, and there is no rivalry to measure.
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Striped patterns.Each round briefly shows a striped pattern (less than a second). If flashing light or striped patterns make you unwell, please skip this experiment.
Self-assessment, not a diagnosis. Mind Atlas helps you reflect on how you experience your inner world. It does not replace medical or psychological advice. Read the disclaimer
Your answers never leave this browser.
Guide
What the binocular rivalry experiment measures
Questionnaires ask how vivid your imagery feels. This experiment looks at something else: whether imagining a colour changes what your eyes see a moment later. It uses binocular rivalry: each eye is shown a different pattern, and instead of blending them, your brain switches between the two.
With red-cyan glasses, one eye sees red stripes and the other cyan stripes. Before the pattern appears, you close your eyes and imagine one colour. Afterwards you report which colour won for a moment: red, mixed or blue. Over many rounds, the share of rounds in which the imagined colour won shows whether your imagery tipped the balance.
What the research found
Pearson, Clifford and Tong (2008) showed that imagining a pattern makes it more likely to dominate the rivalry that follows. In their orientation experiment, the imagined pattern won in 74 % of trials on average, where chance would be 50 %. This was measured in five observers under laboratory conditions.
Keogh and Pearson (2018) used the same kind of task with 15 people who described themselves as aphantasic. Their priming was significantly lower than in a comparison sample of 209 people and did not differ from chance. The method therefore offers a view of imagery that does not rely on self-report alone.
How to read your result
At home the experiment is noisier than in a lab: screen colours, glasses, room light and attention all play a part. Your result is a hint, not a measurement. A value near 50 % means no measurable effect in this session; it does not prove that you have no imagery.
The result is not a diagnosis. It is most interesting next to your questionnaire results: does what you report match what the rivalry shows?
Questions and answers
What do I need?
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Red-cyan 3D glasses (simple paper ones are enough), sound on, and a dim, quiet room for about 15 minutes.
Why an experiment instead of questions?
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Questionnaires rely on how you describe your experience. Binocular rivalry measures whether imagery changes perception, as in Pearson et al. (2008) and Keogh and Pearson (2018).
Is the experiment suitable for everyone?
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Each round briefly shows a striped pattern for less than a second. If flashing light or striped patterns make you unwell, please skip this experiment.
Sources
Pearson J, Clifford CWG, Tong F (2008). The functional impact of mental imagery on conscious perception. Current Biology 18(13):982–986. doi:10.1016/j.cub.2008.05.048
Keogh R, Pearson J (2018). The blind mind: No sensory visual imagery in aphantasia. Cortex 105:53–60. doi:10.1016/j.cortex.2017.10.012
Peer-reviewed studies. Figures are quoted as reported there; your result comes from a self-assessment that has not been validated.
Who makes Mind Atlas
Mind Atlas (mymindatlas.org) is a service by the agency headon. The tests are self-assessments with our own questions and tasks, built on the published research methods listed above. They have not been validated and do not diagnose anything. Your result is calculated in this browser; your answers are not sent to any server.