Background: Previous behavioural and neuroimaging studies of emotion processing in autistic spectrum disorder (ASD) have focused on the use of facial stimuli. To date, however, no studies have examined emotion processing in autism across a broad range of social signals.Method: This study addressed this issue by investigating emotion processing in a group of 23 adults with ASD and 23 age- and gender-matched controls. Recognition of basic emotions (‘happiness’, ‘sadness’, ‘anger’, disgust' and ‘fear’) was assessed from facial, body movement and vocal stimuli. The ability to make social judgements (such as approachability) from facial stimuli was also investigated.Results: Significant deficits in emotion recognition were found in the ASD group relative to the control group across all stimulus domains (faces, body movements and voices). These deficits were seen across a range of emotions. The ASD group were also impaired in making social judgements compared to the control group and this correlated with impairments in basic emotion recognition.Conclusions: This study demonstrates that there are significant and broad-ranging deficits in emotion processing in ASD present across a range of stimulus domains and in the auditory and visual modality; they cannot therefore be accounted for simply in terms of impairments in face processing or in the visual modality alone. These results identify a core deficit affecting the processing of a wide range of emotional information in ASD, which contributes to the impairments in social function seen in people with this condition.

Summary: Studies of face processing have begun to elucidate the brain regions involved in social cognition, which include frontal and temporal regions known to be reduced in volume in schizophrenia. In this case-control study participants with schizophrenia (n=20) showed marked deficits in their ability to interpret social cues from faces, and those experiencing positive symptoms were impaired in recognising even basic facial emotions.

The age, sex, and distinctiveness of faces can be judged from objective and partially independent facial features. In contrast, the physical basis of other social judgements, such as attractiveness, intelligence, and trustworthiness is not as yet entirely understood, despite the consistency of these judgements from faces. The present set of experiments investigated the perception of social characteristics in faces, using an adaptation of the von Restorff/isolation paradigm to determine which social characteristics are spontaneously encoded from the face. The isolation effect involves enhanced memory for perceptually salient items in a list (items that are isolated in the sense that they are in numeric minority) and our results suggested that its locus is at the encoding stage of the recognition memory experiment. Isolation in the present experiments was achieved by manipulating the number of faces included in the sets on the basis of certain characteristics. Because the manipulation of the characteristics of faces in a set to be learnt was not mentioned in most of the experiments, any resulting memory increment for the isolated items could be taken as an index of spontaneous processing of the manipulated social characteristic. Age and sex were found to be spontaneously encoded from faces. Results for other characteristics were mixed, ranging from distinctiveness and attractiveness, for which there was some indication of spontaneous processing, to intelligence and trustworthiness, which did not seem to be spontaneously encoded from faces. For intelligence, an isolation effect was found only when the experiment required a judgement that led to activation of the appropriate stereotype.

Judgments about personality and other social characteristics based on facial appearance are remarkably consistent across individuals. However, whereas the facial cues that underpin age and sex judgments are already well understood, the physical bases for judgments of characteristics such as intelligence or trustworthiness are still unknown. Inversion and photographic negation are used here to investigate the visual processes underlying social inferences from the face and to explore whether various judgments might rely on different perceptual representations. In experiment 1, the perceptions of age, sex, attractiveness, approachability, intelligence, and trustworthiness, but not distinctiveness, were affected by inversion, and all these characteristics were affected by negation. The effects of inversion and negation were independent, suggesting that they impaired the encoding of different types of information. Moreover, an independent manipulation of hue and luminance in experiment 2 showed that the effects of negation were mainly due to the reversal of luminance values. These results are consistent with the view that information about the configuration of features (the processing of which is impaired by inversion) and information about surface properties (the processing of which is impaired by brightness negation) are both used in the perception of social characteristics from faces. In addition, the fact that there was a similar pattern of impairment across most judgments suggests that there is an initial common perceptual representation of the face, from which most characteristics are inferred.