An enlarging hole on the palm illusion and a theory of the moon on the horizon

Area of Science:

• Psychology
• Visual Perception
• Cognitive Science

Background:

• The apparent size of objects can be distorted by surrounding visual information.
• Perceptual constancy, such as size constancy, aims to maintain a stable perception of object size despite changes in retinal image size.
• Illusory size effects, like the palm illusion and the moon illusion, have been subjects of extensive research in visual perception.

Purpose of the Study:

• To propose a unified explanation for the palm illusion and the moon illusion.
• To demonstrate the role of contextual contrast in generating these illusory size perceptions.
• To highlight the mechanism of perceptual constancy in visual illusions.

Main Methods:

• The study theoretically analyzes the conditions under which perceptual constancy operates.
• It examines the role of contextual cues in creating perceived size differences.
• Comparative analysis of the visual fields involved in both the palm and moon illusions.

Main Results:

• Both the palm illusion and the moon illusion are shown to be consequences of perceptual constancy.
• The surrounding context provides a necessary contrast that triggers these constancy mechanisms.
• Illusory size is a byproduct of the brain's attempt to maintain stable perception.

Conclusions:

• Perceptual constancy, modulated by contextual contrast, provides a parsimonious explanation for both the palm and moon illusions.
• Understanding these illusions offers insights into the fundamental principles of visual perception.
• The findings underscore the active and interpretive nature of the human visual system.