adults with a cortical excision. For example, the recall of the Rey figure by children up to about age 8 is not reliably different from that of adults with a right temporal lobectomy (Fig. 6.10).
Face Perception Tests. Like the cognitive tests, there are clear developmental changes in the performance on these tests, changes that vary markedly from test to test. It appears that the ability to locate faces in the closure test improves for a long time even though the processing of faces, as inferred from the composite faces test, is adult-like early. As one might expect, the ability to match facial expressions is mature well before the ability to choose an expression appropriate for a situation.
The development of adult performance on both the cognitive and face perception tasks certainly reflects more than just the development of cortical tissue. In particular, it probably indicates an interaction of experience and cortical development. Significantly, however, the differential developmental rates at different ages show that the tests are probably measuring different abilities and, by inference, different cortical areas. The frontal and temporal cortices are the last to develop, and it is tempting to speculate that the late development of the face cartoon-matching ability reflects the slow development of the temporal cortex. At any rate, it is reasonable to predict from our results that emotional behavior in children will continue to develop until mid to late adolescence.
The goal of this chapter has been to examine the role of the neocortex in the control of emotion. We have shown that damage to the frontal and temporal regions of all mammalian species seems to lead to unambiguous changes in social/affective behavior that are strikingly similar across species. Further, psychiatric disorders that are believed to result from frontal and/or temporal lobe dysfunction produce changes in social/affective behavior that are similar to those observed in neurological patients with frontal or temporal lobe injury. The development of the neural bases of emotional behavior is difficult to study, for normal social interaction surely requires the development of both the requisite neural circuits as well as the learning of sociocultural rules. Nonetheless, it is interesting to note that the frontal and temporal lobes are the last regions to become fully mature in humans, and this anatomical development correlates with certain developmental changes in social and affective behavior in children. We believe the data from our experiments point to a conclusion that the cortex has an important, and vastly underestimated, role in emotional behavior. Most studies of humans to date have emphasized the complementary specialization of the two cerebral hemispheres in the control of emotional behavior, and we too have seen evidence of this in our work. We believe, however, that other factors are as important to