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TopAsd And The 'Synthetic Face Advantage'
The case for including a fully validated set of emotionally expressive cartoon characters in ER research batteries and ER interventions for ASD is strong if we consider the remedial effect that cartoon characters have been noted to have on a number of atypical face processing behaviours characteristic of autism.
Early support for the notion of a cartoon preference in autism comes from a neuroimaging case study that compared the neural activity of a young autistic boy during the viewing of human and synthetic faces. Although there was, as is to be expected in ASD (Hubl et al., 2003; Piggot et al., 2004), no activation of the fusiform face area (an area implicated in face processing) when the boy processed human faces, this atypicality was eliminated when the boy processed cartoon faces (Grelotti et al., 2005). These findings are important as they provide evidence that typical neural functioning seen in response to viewing faces can occur in autism, provided the correct conditions are in place. However, the extent to which results suggesting that cartoon faces elicit typical neural functioning in ASD can be generalised is limited and the exact nature of the correct conditions remains elusive, given that the study used a single case study and the cartoon characters used were familiar to the participant.
In 2006, Lahaie et al. demonstrated that people with ASD generally adopt a 'local' or piecemeal approach when processing human faces, in contrast to the configural processing and recognition strategies typically employed by non-autistic individuals. In neurotypical individuals, human faces are perceived as special and as such are processed in a different manner to non-face stimuli. Typically, for face stimuli, the processing applied attempts to process the input globally rather than serial-analytically, possibly because global processing (an appreciation of the spatial configuration of facial features) has been found to be advantageous in face recognition (e.g. Brunelli and Poggio, 1993). In contrast, individuals with ASD do not appear to perceive human face stimuli as anything 'special' and thus process the human face in much the same way as they would any other object in the environment, utilising elemental rather than configural processing and recognition strategies. The use of this less effective local, feature-based processing strategy in ASD has been suggested to underlie the deficits in emotion recognition in autism (Teunisse & de Gelder, 2001). However, Rosset et al. (2008) showed that, generally, ASD children do adopt the typical global strategy when processing cartoon faces, i.e., in the same way as non-autistic children do when they process human faces.
Synthetic characters and faces also appear to normalise a number of other face processing behaviours such as gaze activity (van der Geest et al., 2002). It has been repeatedly demonstrated that in social situations people with ASD fixate, not on the human face (which provides contextual clues critical to social understanding), but instead on socially irrelevant details, such as objects in the environment (Klin et al., 2002). This atypical behaviour, apparent from the very first months of life (Swettenham et al., 1998) has been argued by some to be the result of abnormal social preferences, and, due to the inevitable reduction in face appraisal opportunities, may play a role in the socio-emotional processing impairments characteristic of ASD (Riby, Doherty-Sneddon, and Bruce, 2008). However, this atypical gaze behaviour does not extend to cartoon faces. Van der Geest et al. (2002) found that ASD individuals fixated on a cartoon drawing of a human figure more frequently and for longer periods than they fixated on an object.
Collectively, the above evidence appears to suggest that the neural activation patterns, perceptual strategies and face processing behaviours of ASD individuals in response to cartoon faces mirror those of non-autistic individuals in response to human faces and suggests that cartoon faces may hold the same special social (and cognitive) relevance that human faces hold for typically developing individuals. Given this, it may be crucially important to integrate them into face-processing therapeutic interventions for those with ASD.