Susceptibility to spatial illusions does not depend on visual experience: Evidence from sighted and blind children

Area of Science:

• Cognitive Psychology
• Neuroscience
• Developmental Psychology

Background:

• Visuospatial illusions are perceptual distortions that can arise from learned environmental regularities or sensory mechanism recruitment.
• Previous research suggests illusions may involve amodal perceptual inferences, as young children and blind adults exhibit susceptibility.
• Conflicting evidence exists, with some studies indicating innate mechanisms contribute to illusions, particularly in the newly sighted.

Purpose of the Study:

• To investigate the role of sensory and cognitive influences on visuospatial illusions.
• To differentiate between innate and learned components of illusion susceptibility.
• To explore cross-modal interactions in the perception of spatial illusions.

Main Methods:

• Investigated susceptibility to Ebbinghaus, Müller-Lyer, and Vertical-Horizontal illusions in children aged 6-14 using visual, haptic, and bimodal exploration.
• Tested 17 congenitally blind children for haptic susceptibility to illusions.
• Analyzed age-related changes in illusion susceptibility.

Main Results:

• Children of all ages were susceptible to the three visual illusions.
• Haptic exploration alone induced illusions of extent, but not size.
• Congenitally blind children demonstrated susceptibility to haptic illusions, similar to sighted children.
• Reduced susceptibility in older children suggested explicit spatial knowledge is not the primary mediator.

Conclusions:

• Visual experience is not essential for perceiving spatial illusions.
• Spatial illusions appear to be driven by innate developmental processes.
• These innate processes are not entirely vision-dependent but are refined by visual input.
• Cross-modal interactions in brain regions typically associated with vision may underlie illusion perception.