When 2 become 1: Autistic simultaneity judgements about asynchronous audiovisual speech.

Area of Science:

• Neuroscience
• Psychology
• Autism Research

Background:

• Previous research suggested autistic individuals have altered temporal processing, specifically an extended temporal binding window for multisensory integration.
• These findings were primarily observed in children, leaving adult temporal processing in autism understudied.
• The role of response bias versus perceptual differences in prior observations remained unclear.

Purpose of the Study:

• To investigate whether autistic adults exhibit an extended temporal binding window for audiovisual speech.
• To differentiate between perceptual processing efficiency and response bias in autistic adults.
• To determine if proposed temporal distortions persist into adulthood.

Main Methods:

• Participants performed simultaneity judgments on audiovisual speech stimuli presented at various onset asynchronies.
• Drift-diffusion modeling was used to estimate processing efficiency (drift rate) and response bias (starting point).
• Experiment 1 analyzed correlations between Autism Quotient scores and model parameters in non-autistic adults; Experiment 2 compared autistic and non-autistic adults.

Main Results:

• Autism Quotient scores in non-autistic adults did not correlate with drift rate or starting point.
• No significant between-group differences in drift rate or starting point were found when comparing autistic and non-autistic adults.
• Exploratory analyses indicated that operationalizing the temporal binding window differently affected observed group differences.

Conclusions:

• The study does not support the hypothesis of an extended temporal binding window for audiovisual speech in autistic adults.
• Perceptual processing efficiency and response bias for audiovisual speech appear similar between autistic and non-autistic adults.
• Methodological choices in defining the temporal binding window can influence findings, highlighting the need for careful consideration in future research.