Autistic individuals show less grouping-induced bias in numerosity judgments

Area of Science:

• Cognitive Psychology
• Neurodevelopmental Disorders

Background:

• Perception of connected items can lead to underestimation of quantity.
• Autistic-like traits in neurotypical adults influence grouping biases in numerosity perception.

Purpose of the Study:

• To investigate if grouping-induced numerosity biases observed in neurotypical adults extend to individuals with Autism Spectrum Disorder (ASD).
• To explore differences in visual perception and grouping mechanisms between autistic and neurotypical populations.

Main Methods:

• Twenty-two adults with ASD and 22 matched neurotypical controls estimated the numerosity of connected dot-pairs.
• Participants judged the quantity of dot clouds presented with varying degrees of connectivity.

Main Results:

• No significant difference in task performance precision between the ASD and neurotypical groups.
• Autistic participants showed significantly less bias in numerosity estimation due to item grouping compared to neurotypical controls.
• The strength of grouping effects in neurotypical individuals correlated with autistic-like traits.

Conclusions:

• Autistic perception differs in how visual grouping affects the estimation of quantity.
• Findings support theories of autistic perception emphasizing global versus local processing differences.
• Numerosity estimation can serve as an indirect method to study perceptual grouping mechanisms.