Research Article Autistic Traits Affect P300 Response to Unexpected Events, regardless of Mental State Inferences Mitsuhiko Ishikawa, 1 Shoji Itakura, 1 and Hiroki C. Tanabe 2 1 Graduate School of Letters, Kyoto University, Kyoto, Japan 2 Graduate School of Environmental Studies, Nagoya University, Nagoya, Japan Correspondence should be addressed to Mitsuhiko Ishikawa; ishikawa.mitsuhiko.23r@st.kyoto-u.ac.jp 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. Tis 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 difculties inferring others’ mental states. Here, we examined how individuals with diferent levels of autistic traits respond to contextual deviations by measuring event- related potentials that refect context usage. Te Autism Spectrum Quotient (AQ) was used to quantify autistic-like traits in 28 university students, and 19 participants were defned 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 fnal 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. Tis suggests that autistic traits can afect responses to unexpected events, possibly because of decreased availability of context information. 1. Introduction Tere is a general assumption that, in order to interact with and have smooth relationships with others in society, one must master certain social behaviors such as empathizing with others, understanding humour, seeing through lies, and comprehending ironies. A diagnosis of autism spectrum dis- order (ASD) indicates difculties with these social behaviors, which are required for understanding others’ beliefs, desires, and intentions (termed “theory of mind” [1]). It has been argued that the foundation of social difculties may be the absence of a theory of mind [2]. However, Happ´ e [3] revealed that children with ASD can obtain a theory of mind, albeit with some developmental delay. Subsequently, explanations for problems associated with ASD began to focus on the ways that theory of mind is used in social situations. One such explanation involves the idea of context blindness [4], which, for people with ASD, refers to difcul- ties with the spontaneous use of context in social situations. For instance, to accurately appraise emotions based on another person’s facial expressions, we must think about con- textual information, such as the events afecting or surround- ing the person. Additionally, understanding irony and sar- casm depends heavily on context. Tere is an example in the Strange Stories test that assesses theory of mind [4]: Emma takes a banana, holds it against her ear, and then says “Look, this banana is a telephone!” In this story, what Emma said is not literally true, but we can understand through context that it is about pretending. Terefore, the use of theory of mind in social situations may be related to the spontaneous use of contextual information. For the purposes of the context blindness hypothesis, context is defned as not only the fow of linguistic informa- tion, but also any type of global information, including that based on visual perceptual. Te frst global hypothesis states that weak central coherence (WCC [5, 6]) explains defcits in the use of global information in people with ASD. Tis theory asserts that people with ASD are not inclined to perceive Hindawi Autism Research and Treatment Volume 2017, Article ID 8195129, 10 pages https://doi.org/10.1155/2017/8195129