https://www.procreo.jp/labo/labo13.html
Watch this video. Do you see the dancer turning to the left?
Keep watching. Now, do you see her turning to the right?
The spinning dancer illusion has stumped viewers for years. Is the dancer actually changing directions, or is it just your brain playing tricks on you?
This video was made by a Japanese web designer named Noboyuki Kayahara in 2003 (Lucafò et. al. 2016).
Previously, I have talked about the concept of an image being multistable/bistable. Similar to images, this video can also be perceived as bistable because your brain can perceive the dancer as spinning in both the clockwise (CW) and counterclockwise (CCW) directions. Your brain maintains only one direction until prompted to switch because it settles on one interpretation until more evidence is accumulated to push it to change. In this case, my prompting you to look again would be sufficient evidence for your brain to look for a different visual interpretation of this video (Lucafò et. al., 2016).
In a study conducted by Bernal, it was found that a different hemisphere of the brain is activated for each iteration of the video (CW and CCW). This shows that different brain states are present for the subjective perception of a visual input. These differences in perception reflected spontaneous brain fluctuations in top-down sensory processing (Bernal et. al, 2014).
The ability of the brain to “flip” an interpretation of a visual input is a topic that has only been researched in recent years. The spinning dancer illusion is a simple and easy to measure and provides a strong basis for future studies in neural perception and attention.
References
Bernal, B., Guillen, M., & Marquez, J. C. (2014). The spinning dancer illusion and spontaneous brain fluctuations: An fMRI study. Neurocase, 20(6), 627-639.
Lucafò, C., Marzoli, D., Prete, G., & Tommasi, L. (2016). Laterality effects in the spinning dancer illusion: The viewing‐from‐above bias is only part of the story. British Journal of Psychology, 107(4), 698-709.
