Frontal EEG asymmetry in infants observing separation and comforting events: The role of infants' attachment relationship.

The development of social-cognitive abilities in infancy is subject to an intricate interaction between maturation of neural systems and environmental input. We investigated the role of infants' attachment relationship quality in shaping infants' neural responses to observed social interactions. One-hundred thirty 10-month-old infants participated in an EEG session while they watched animations involving a distressing separation event that ended with either comforting or ignoring behavior. Frontal asymmetry (FA) in the alpha range - which is indicative of approach-withdrawal tendencies - was measured with EEG. Attachment quality was assessed using the Strange Situation procedure at 12 months. Overall, infants with disorganized attachment showed a lack of right-sided - withdrawal related - FA compared to secure and insecure infants. Furthermore, only avoidant infants exhibited reduced right-sided FA responses following the separation. Contrary to our expectations, the type of response (comforting vs. ignoring) did not elicit differences in FA patterns, and attachment quality did not moderate the effects of the type of response on frontal asymmetry. Implications for research on attachment-related biases in social information processing and on the neural underpinnings of prosocial behaviors are discussed.