Recent findings from both animal and human research have clearly demonstrated connections between behavioral coping mechanisms and adrenocortical function. The aim of this study was to address the role of maternal sensitivity as an external organizer of psychobiological function in infants during the first year of life. Forty-one infants and their mothers were observed during play at 3, 6, and 9 months of age. Age-specific patterns of relation between maternal sensitivity and infant behavioral organization were found indicating contextual dependence of infant behavior at 3 months and experience-related behavioral function at 9 months. An affect of maternal sensitivity on adrenocortical function during the free play was demonstrated at 3 and 6 months, because an increase in cortisol was most frequently observed in infants of highly insensitive mothers. The findings indicate the importance of maternal behavior for infant biobehavioral organization.

The aim of the study was to investigate parental perception and interpretation of infant emotional expression depending on their attachment representation. Forty-six parents' responses to infant pictures depicting positive, neutral, and negative emotions were assessed on the level of affective judgments (valence, arousal), mimic responses (facial muscle activity), and of the eyelid reflex (using the startle paradigm). Results revealed small differences between parents of different attachment representations with respect to their subjective evaluations. However, secure parents, as compared to insecure ones, showed a positive bias in their mimic responses to infant pictures. The modulation of the startle response indicated a negative evaluation of negative infant emotion expressions in dismissing parents, while an augmentation of the startle response to negative infant emotions could not be observed in secure and preoccupied parents. The findings highlight the role of attachment experiences for emotional information processing in parents and its consequences for parental behavior.