| Although the ability to identify emotions conveyed by facial expressions is crucial for human social communication, how this ability develops has not been studied extensively, especially during middle childhood. To better understand the processes responsible for the development of facial expression recognition, this study recorded children's eye movements while they made judgments about facial expressions. This provides psychophysiological evidence of how visual attention is directed to faces. Previous eye-tracking studies, have examined facial expression processing in clinical samples, but not in typically developing children. This study examined 8-year-olds; 12-year-olds, and adults on four experiments. The goals were to study the accuracy and efficiency of facial expression processing in middle childhood, and to investigate whether eye-tracking measures are informative about performance changes across these ages. Results from Experiment 1 indicate that accuracy improved with age when participants identified facial expressions, but not non-face objects (vehicles). Response times improved with age on both tasks. In Experiment 2 eye movements were recorded during a similar facial expression identification task. Results showed that 8-year-olds made the most visual fixations, but fixation durations and the distribution of fixations to facial features did not vary by age. Few differences in fixation patterns were found across expressions, but more occurred for the inverted faces. In Experiment 3, participants demonstrated categorical perception of facial expressions, but response patterns were similar across ages. While the number of fixations decreased with age, the pattern of fixations to facial features did not vary across images. Experiment 4 found age differences in manual response bias for angry expressions on the visual probe task. Across groups, saccades were directed away from angry faces, suggesting avoidance of this expression. Overall, the behavioral results demonstrate developmental changes during middle childhood on a variety of facial expression processing tasks. The eye-tracking results show some age-related effects, but few differences across facial expressions This demonstrates the utility of eye-tracking for investigating the development of facial expression processing. However, limitations exist in what this method can detect. These findings have implications for future eye-tracking studies of facial expression processing in typically developing children and children with clinical disorders. |
