Hemispheric Specialization and Attachment Behaviors: Developmental Processes and Individual Differences in Separation Protest
Nathan A. Fox
Richard J. Davidson
The infant's distress response to brief maternal separation appears during the last quarter of the first year of life and diminishes during the second year. Its significance has been highlighted by a number of theorists working in the area of the attachment relationship between mother and child. Research from our laboratories on cerebral asymmetry and the development of emotion has begun to characterize both the developmental course of separation protest and variations in the intensity of the distress response. Data presented in this chapter indicate that the development of separation protest may be associated with the relative activation of certain regions in the cerebral hemispheres. Ten-month-old infants who exhibited distress at separation displayed greater right frontal activation during separation as compared to infants who did not protest. Differences in relative frontal activation during protest are interpreted as signifying the presence or absence of active inhibition, via the left hemisphere, of right frontal negative affect. In addition, ten-month-old infants who displayed greater relative right frontally-mediated activation during a baseline recording were more likely to exhibit distress at separation than those displaying left frontal activation. Interpretation of these data are consistent with a model emphasizing the role of the two cerebral hemispheres in the expression of both positive and negative emotion and in the display of different affective styles.
The purpose of this chapter is to review research on the possible physiological substrates of the infant's behavior in response to brief separation from mother that occurs during the last half of the first year and into the second year of life. This response pattern has been called separation protest or separation anxiety in the psychological literature ( Bowlby, 1958). The infant's distress at separation from its mother has long been viewed as an important indicator of attachment