POSTNATAL FORAGING DEMANDS ALTER ADRENOCORTICAL ACTIVITY AND PSYCHOSOCIAL DEVELOPMENT

Mother squirrel monkeys stop carrying infants at earlier ages in high- demand (HD) conditions where food is difficult to find relative to low -demand (LD) conditions. To characterize these transitions is psychoso cial development, from 10- to 21-weeks postpartum we collected measure s of behavior, adrenocortical activity, and social transactions coded for initiator (mother or infant), goal (make-contact or break-contact) , and outcome (success or failure). Make-contact attempts were most of ten initiated by HD infants, but mothers often opposed these attempts and less than 50% were successful. Break-contact attempts were most of ten initiated by LD infants, but mothers often opposed these attempts and fewer LD than HD infant break-contact attempts were successful. Pl asma levels of cortisol were significantly higher in HD than LD mother s, but differences in adrenocortical activity were less consistent in their infants. HD and LD infants also spend similar amounts of time nu rsing on their mothers and feeding on solid foods. By rescheduling som e transitions in development (carry --> self-transport), and not other (nursing --> self-feeding), mothers may have partially protected infa nts from the immediate impact of an otherwise stressful foraging task. (C) 1998 John Wiley & Sons, Inc.