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Autism Research and Treatment
Volume 2017 (2017), Article ID 8195129, 10 pages
Research Article

Autistic Traits Affect P300 Response to Unexpected Events, regardless of Mental State Inferences

1Graduate School of Letters, Kyoto University, Kyoto, Japan
2Graduate School of Environmental Studies, Nagoya University, Nagoya, Japan

Correspondence should be addressed to Mitsuhiko Ishikawa

Received 22 December 2016; Revised 18 March 2017; Accepted 9 April 2017; Published 4 June 2017

Academic Editor: Robert F. Berman

Copyright © 2017 Mitsuhiko Ishikawa et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Limited use of contextual information has been suggested as a way of understanding cognition in people with autism spectrum disorder (ASD). However, it has also been argued that individuals with ASD may have difficulties inferring others’ mental states. Here, we examined how individuals with different levels of autistic traits respond to contextual deviations by measuring event-related potentials that reflect context usage. The Autism Spectrum Quotient (AQ) was used to quantify autistic-like traits in 28 university students, and 19 participants were defined as Low or High AQ groups. To additionally examine inferences about mental state, two belief conditions (with or without false belief) were included. Participants read short stories in which the final sentence included either an expected or an unexpected word and rated the word’s degree of deviation from expectation. P300 waveform analysis revealed that unexpected words were associated with larger P300 waveforms for the Low AQ group, but smaller P300 responses in the High AQ group. Additionally, AQ social skill subscores were positively correlated with evaluation times in the Unexpected condition, whether a character’s belief was false or not. This suggests that autistic traits can affect responses to unexpected events, possibly because of decreased availability of context information.