Abnormal patterns of cerebral lateralisation as revealed by the Universal Chimeric Faces Task in individuals with autistic disorder.

A previous study by Workman, Chilvers, Yeomans, and Taylor (2006), using the "Universal" Chimeric Faces Task (UCFT) for six emotional expressions, demonstrated that an overall left hemispatial/right hemisphere (RH) advantage has begun to develop by the age of 7-8. Moreover, the development of this left hemispatial advantage was observed to correlate positively with the ability to read emotions in the faces of others. Adopting the UCFT, the current study compared autistic children (11-15) with unimpaired children of two age groups (5-6 and 7-8) from this previous study. The autistic children showed a left hemispatial/RH advantage only for the two emotional expressions of "happiness" and "anger". Results for the autistic children revealed a similar overall pattern of lateralisation to the 5-6-year-olds and one that is less lateralised than the pattern for the 7-8-year-olds. Autistic children appear to show a developmental deficit for left hemispatial/RH advantage for emotional expression with the exception of "happiness" and "anger." The findings are discussed in terms of role hemisphericity and an approach-avoidance model.

Development of cerebral lateralisation for recognition of emotions in chimeric faces in children aged 5 to 11.

In contrast to research into the development of language laterality, there has been relatively little research into the development of lateralisation of emotional processing. If language lateralisation begins in childhood and is complete by puberty (Lenneberg, 1967) it seems reasonable that the lateralisation of the perception of emotions might also occur during this period. In this study a split field chimeric faces test using the six universal facial expressions proposed by Ekman and Friesen (1971), an emotion in the eyes test, and a situational cartoon test were administered to three groups of children aged 5/6, 7/8, and 10/11. No overall hemispace advantage was seen for the 5/6-year-old group, but by the age of 10/11 a clear left hemispace advantage (right hemisphere) was found for all six emotions. Such a pattern is comparable to a previous study that made use of adults on this task (Workman, Peters, & Taylor, 2000b). Moreover, a significant positive correlation between a child's ability to recognise emotions in cartoon situations and their left hemispatial advantage score was uncovered. Finally, a significant positive correlation between a child's ability to recognise emotions in the eyes of others and their left hemispatial advantage score was also uncovered. These findings are taken as evidence that there may be a relationship between the development of emotional processing in the right hemisphere and a child's emerging ability to perceive or attend to the emotional states of others. Results are discussed in relation to the child's development of a theory of mind.