The role of interpersonal synchrony in forming impressions of autistic and non-autistic adults.

When people meet, they almost instantaneously form an impression of each other. First impressions of character traits and rapport are less favourable when people with autism spectrum condition (ASC) are judged compared to non-autistic people. Little is known about the behavioural differences that drive these altered impressions. In the present study, we investigated the influence of interpersonal synchrony on impression formation of autistic and non-autistic people. Specifically, we used lagged cross-correlations to assess how much each interactant's motion energy, a measure which can be determined from video recordings, influenced the other interactant's motion energy. In short, silent clips of dyadic conversations, we asked non-autistic participants to rate their impression of one of the two interactants, which was solely based on the outlines of both interactants. We expected that the amount of leading of the target interactant, their diagnostic status as well as the interaction of these factors would influence impression formation. We found that while the amount of leading had a positive effect on the impressions of non-autistic interactants, this was not true for interactants with ASC. This suggests that interpersonal synchrony of motion energy is one driver of less favourable impressions of autistic compared to non-autistic people.

Reduced nonverbal interpersonal synchrony in autism spectrum disorder independent of partner diagnosis: a motion energy study.

BACKGROUND: One of the main diagnostic features of individuals with autism spectrum disorders is nonverbal behaviour difficulties during naturalistic social interactions. The 'Interactional Heterogeneity Hypothesis' of ASD proposes that the degree to which individuals share a common ground substantially influences their ability to achieve smooth social interactions. METHODS: To test this hypothesis, we filmed 29 autistic and 29 matched typically developed adults engaged in several conversational tasks. Windowed cross-lagged correlations were computed using the time series of motion energy of both individuals in a dyad. These coefficients were then compared across the three dyad types that were homo- or heterogenous with respect to diagnosis: pairs of two autistic individuals, two typically developed individuals or pairs of one autistic and one typically developed person. RESULTS: We found that all dyad types achieved above-chance interpersonal synchrony, but that synchrony was more expressed in typical dyads compared to both autistic and mixed dyads. LIMITATIONS: The method presented here provides only one, albeit objective and robust, approach to explore synchrony. The methodological choices as well as the lack of consideration for other communication modalities may limit our interpretation of the findings. Moreover, the sample size is small with respect to exploring associations between synchrony and various outcome and social skill measures. CONCLUSIONS: The present results do not provide support for the Interactional Heterogeneity Hypothesis given that autistic individuals do not coordinate better when interacting with another autistic individual, compared to when interacting with a typical individual.

Neural correlates of "social gaze" processing in high-functioning autism under systematic variation of gaze duration.

Direct gaze is a salient nonverbal signal for social interest and the intention to communicate. In particular, the duration of another's direct gaze can modulate our perception of the social meaning of gaze cues. However, both poor eye contact and deficits in social cognitive processing of gaze are specific diagnostic features of autism. Therefore, investigating neural mechanisms of gaze may provide key insights into the neural mechanisms related to autistic symptoms. Employing functional magnetic resonance imaging (fMRI) and a parametric design, we investigated the neural correlates of the influence of gaze direction and gaze duration on person perception in individuals with high-functioning autism (HFA) and a matched control group. For this purpose, dynamically animated faces of virtual characters, displaying averted or direct gaze of different durations (1 s, 2.5 s and 4 s) were evaluated on a four-point likeability scale. Behavioral results revealed that HFA participants showed no significant difference in likeability ratings depending on gaze duration, while the control group rated the virtual characters as increasingly likeable with increasing gaze duration. On the neural level, direct gaze and increasing direct gaze duration recruit regions of the social neural network (SNN) in control participants, indicating the processing of social salience and a perceived communicative intent. In participants with HFA however, regions of the social neural network were more engaged by averted and decreasing amounts of gaze, while the neural response for processing direct gaze in HFA was not suggestive of any social information processing.