Müller-Lyer Illusion susceptibility is conditionally predicted by autistic trait expression

Area of Science:

• Cognitive psychology
• Neuroscience
• Autism research

Background:

• The Müller-Lyer (ML) illusion consistently biases size perception.
• Autistic individuals may exhibit altered responses to illusory stimuli.
• Autistic trait expression can modulate perceptual biases.

Purpose of the Study:

• To investigate the correlation between autistic traits and ML illusion susceptibility.
• To examine how different ML illusion presentation methods affect bias magnitude.
• To explore the role of the Autism-Spectrum Quotient (AQ) and Systemizing Quotient (SQ) in modulating perceptual biases.

Main Methods:

• Thirty neurotypical adults completed AQ and SQ questionnaires.
• Participants performed four ML illusion size estimation tasks (concurrent/successive discrimination, line adjustment, figure adjustment).

Main Results:

• Overall performance did not correlate with autistic traits.
• A negative correlation was found between AQ and bias when adjusting complementary illusory figures (Task 4).
• Illusory biases were stronger with concurrent ML figure presentation.

Conclusions:

• Increased AQ may reduce ML illusion susceptibility, specifically when adjusting concurrent illusory figures.
• Perceptual biases can be modulated by autistic traits within a neurotypical population.
• Method of illusion measurement significantly impacts observed illusory bias magnitude.