Binocular disparity as an explanation for the moon illusion

Distance cues to the horizon allow our perception to estimate the distance to the sky, resulting in a strong illusory phenomenon. Absence of distance cues at the zenith cause our  perception to be unable to estimate distance to the sky, resulting in a weak illusory phenomenon.

Distance cues to the horizon allow our perception to estimate the distance to the sky,
resulting in a strong illusory phenomenon. Absence of distance cues at the zenith cause our
perception to be unable to estimate distance to the sky, resulting in a weak illusory phenomenon.

Joseph Antonides, Toshiro Kubota
We present another explanation for the moon illusion, in which the moon looks larger near the horizon than near the zenith. In our model, the sky is considered a spatially contiguous and geometrically smooth surface. When an object (like the moon) breaks the contiguity of the surface, humans perceive an occlusion of the surface rather than an object appearing through a hole. Binocular vision dictates that the moon is distant, but this perception model dictates that the moon is closer than the sky. To solve the dilemma, the brain distorts the projections of the moon to increase the binocular disparity, which results in increase of the angular size of the moon. The degree of the distortion depends upon the apparent distance to the sky, which is influenced by the surrounding objects and the condition of the sky. The closer the sky appears, the stronger the illusion. At the zenith, few distance cues are present, causing difficulty with distance estimation and weakening the illusion.
Read more: http://arxiv.org/ftp/arxiv/papers/1301/1301.2715.pdf

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.