Mark S. Strauss

While it is well-known that individuals with autism spectrum disorder (ASD) have difficulties processing faces, very little is known about the origins of these deficits. The current study focused on 6- and 11-month-old infants who were at either high-risk (n = 43) or low-risk (n = 31) for developing ASD based on having a sibling already diagnosed with the disorder. Eye-tracking data were collected while the infants viewed color photographs of faces. Similar to previous studies with both typically developing adults and infants, low-risk infants demonstrated a preference for looking at the left side of the face (known as a left visual field bias) that emerged by 11 months of age. In contrast, high-risk infants did not demonstrate a left visual field bias at either age. Comparisons of the amount of attention given to the eye versus mouth regions indicated no differences between the two risk groups.

While much research has examined the development of facial recognition abilities, less is known about the ability of individuals with and without autism to categorize facial gender. The current study tested gender categorization abilities in high-functioning children (5–7 and 8–12 years), adolescents (13–17 years), and adults (18–53 years) with autism and matched controls. Naturalistic videos depicted faces that were either typical or less typical of each gender. Both groups improved in their performance across development. However, control children reached expertise that was similar to control adults by 8–12 years; whereas, adults with autism never reached this level of expertise, particularly with less typical gender faces. Results suggest that individuals with autism employ different face processing mechanisms than typically developing individuals.

It has been established that typically developing individuals have a bias to attend to facial information in the left visual field (LVF) more than in the right visual field. This bias is thought to arise from the right hemisphere’s advantage for processing facial information, with evidence suggesting it to be driven by the configural demands of face processing. Considering research showing that individuals with autism have impaired face processing abilities, with marked deficits in configural processing, it was hypothesized that they would not demonstrate a LVF bias for faces. Eye-tracking technology was used to show that individuals with autism were not spontaneously biased to facial information in the LVF, in contrast to a control group, while discriminating facial gender.

There is a growing amount of evidence suggesting that individuals with autism have difficulty with face processing. One basic cognitive ability that may underlie face processing difficulties is the ability to abstract a prototype. The current study examined prototype formation with natural faces using eye-tracking in high-functioning adults with autism and matched controls. Individuals with autism were found to have significant difficulty forming prototypes of natural faces. The eye-tracking data did not reveal any between group differences in the general pattern of attention to the faces, indicating that these difficulties were not due to attentional factors. Results are consistent with previous studies that have found a deficit in prototype formation and extend these deficits to natural faces.

This chapter illustrates how the current field of infant and adult cognitive theories can elucidate some the mysteries of autistic symptomatology. It first reviews the prevailing cognitive theories of autism, followed by a review of the growing body of evidence that autistic symptoms are present during infancy. It then describes how the current research on deficits in autism fit with theories of the categorization of objects and faces. These findings are presented against a backdrop of an information-processing approach. Finally, the chapter presents data linking categorization theories with symptoms of autism and illustrates how the methods can be applied to identifying autism during infancy.

Evidence remains mixed about whether individuals with autism look less to eyes and whether they look more at mouths. Few studies have examined how spontaneous attention to facial features relates to face processing abilities. This study tested the ability to discriminate gender from facial features, namely eyes and mouths, by comparing accuracy scores of 17 children with autism and 15 adults with autism to 17 typically developing children and 15 typically developing adults. Results indicated that all participants regardless of diagnosis discriminated gender more accurately from eyes than from mouths. However, results indicated that compared to adults without autism, adults with autism were significantly worse at discriminating gender from eyes.

Little is known regarding metacognition in individuals with autism. Specifically, it is unclear how individuals with autism think about their own mental states. The current study assessed memory awareness during a facial recognition task. High-functioning children (M = 13.1 years, n = 18) and adults (M = 27.5 years, n = 16) with autism matched with typically developing children (M = 14.3 years, n = 13) and adults (M = 26.9 years, n = 15) were tested. Children with autism demonstrated less accurate memory awareness for faces and less reliable differentiation between their confidence ratings compared to typically developing children. Subtle impairments in memory awareness for faces were also evident in adults with autism. Results indicate that broader metacognitive deficits may exist in individuals with autism, possibly contributing to other known impairments.

Prototype formation is a critical skill for category learning. Research suggests that individuals with autism may have a deficit in prototype formation of some objects; however, results are mixed. This study used a natural category, faces, to further examine prototype formation in high‐functioning individuals with autism. High‐functioning children (age 8–13 years) and adults with autism (age 17–53 years) and matched controls were tested in a facial prototype formation task that has been used to test prototype formation abilities in typically developing infants and adults [Strauss, 1979]. Participants were familiarized to a series of faces depicting subtle variations in the spatial distance of facial features, and were then given a forced choice familiarity test between the mean prototype and the mode prototype. Overall, individuals in the autism group were significantly less likely to select the mean prototype face. Even though the children with autism showed this difference in prototype formation, this pattern was driven primarily by the adults, because the adults with autism were approximately four times less likely to select the mean prototype than were the control adults. These results provide further evidence that individuals with autism have difficulty abstracting subtle spatial information that is necessary not only for the formation of a mean prototype, but also for categorizing faces and objects.

Emotion recognition was investigated in typically developing individuals and individuals with autism. Experiment 1 tested children (5–7 years, n = 37) with brief video displays of facial expressions that varied in subtlety. Children with autism performed worse than the control children. In Experiment 2, 3 age groups (8–12 years, n = 49; 13–17 years, n = 49; and adults n = 45) were tested on the same stimuli. Whereas the performance of control individuals was best in the adult group, the performance of individuals with autism was similar in all age groups. Results are discussed with respect to underlying cognitive processes that may be affecting the development of emotion recognition in individuals with autism.

This study examined the effect of exemplar typicality on reaction time and accuracy of categorization. High-functioning children (age 9–12), adolescents (age 13–16), and adults with autism (age 17–48) and matched controls were tested in a category verification procedure. All groups showed improved processing throughout the lifespan for typical and somewhat typical category exemplars. However, individuals with autism responded more slowly than matched controls to atypical exemplars at all ages. The results are discussed in terms of potential differences in the type of processing that may be required for categorizing typical and atypical category exemplars. Parallels are also drawn to the results of previous studies on face processing in individuals with autism.