Can the Perception of Time Be Modulated by Emotional Stimuli in Individuals with Autism Spectrum Disorders?

Background: It has been established that temporal judgments (judgments about the duration of stimuli) can be distorted by the emotional salience of stimuli. For example, in the temporal bisection task the duration of an emotionally expressive face (e.g. happy, angry, fearful) is typically overestimated compared to a neutral facial expression (e.g. Droit-Volet et al., 2004). It is hypothesized that this effect is driven by stimulus-induced increases in arousal, which speed the rate of an ‘internal clock’ that meters time. To date, performance on this task has not been explored in individuals with autism spectrum disorders (ASD). If individuals with ASD show overestimation of emotional stimuli then it would suggest that their implicit responsiveness to emotional cues is intact. However, the absence of the effect would indicate an atypical response to emotion.

Objectives: To establish whether temporal judgements in people with ASD or those with a high degree of self-reported autistic traits are modulated by the emotional salience of stimuli.

Methods: Participants were presented with the classic time bisection task in which they learnt two standard intervals, one ‘short’ (400 ms) and one ‘long’ (1600 ms). During the testing phase they were presented with a variety of stimuli of intermediate durations and had to classify them as either more similar to the short or the long standards. In two conditions, temporal judgements were assessed for face stimuli (angry, happy, fearful and neutral faces) and non-face stimuli (snarling dog, cute puppy, spider and flower) that varied in emotional salience. The relative change in GSR during presentation of the different stimuli was also monitored.

Results: Data collection is still in progress. We will report data collected from two cohorts of participants: 1) a large group of young adults with varying Autism Quotient (AQ) scores and 2) two groups of age- and IQ-matched adults with and without a clinical diagnosis of ASD. 

Conclusions: The results will establish whether autistic traits impact upon implicit responsiveness to emotional face and non-face images. This has implications for understanding how emotional stimuli are processed in ASD and, more broadly, will give insight into the subjective perceptual experience of individuals with ASD. Preliminary analyses suggest differential performance in those with ASD.