Lexical effects on speech perception in individuals with "autistic" traits

Area of Science:

• Psycholinguistics
• Neuroscience
• Developmental Psychology

Background:

• Autism Spectrum Disorder (ASD) is linked to difficulties integrating contextual information with perceptual stimuli.
• A nonholistic processing style, associated with ASD, may also be present subtly in neurotypicals.
• The Ganong effect, a phonetic categorization phenomenon, offers a potential avenue to study this in neurotypicals.

Purpose of the Study:

• To investigate if autistic traits in neurotypicals correlate with a reduced Ganong effect.
• To explore the relationship between autistic traits and auditory speech perception processing.
• To determine if a nonholistic processing style underlies autistic traits in the general population.

Main Methods:

• Fifty-five university students completed the Autism-Spectrum Quotient (AQ).
• Participants underwent a segment identification test using two Voice Onset Time (VOT) continua (kiss-giss, gift-kift).
• VOT discrimination, auditory lexical decision, and verbal IQ were also assessed.

Main Results:

• A significant negative correlation was observed between AQ scores and the magnitude of the Ganong effect.
• Higher AQ scores were associated with a weaker shift in phonetic categorization towards known words.
• No correlation was found between AQ scores and VOT discrimination, lexical access, or verbal IQ.

Conclusions:

• Autistic traits in neurotypicals are associated with altered auditory speech perception, specifically a weaker Ganong effect.
• This suggests that a more context-independent processing style may be linked to autistic traits.
• The findings rule out auditory sensitivity, lexical access speed, or verbal intelligence as explanations for this effect.