Bowlby's original formulation of attachment behavior relied heavily on ethology, especially nonhuman primate studies. Shedding light on behaviors by analyzing nonhuman primate behavior, especially in naturalistic settings, is one of the longstanding goals of ethological studies. This study of free-ranging rhesus macaques will further our understanding of the lasting effects of infant attachment behavior and the extent to which evolution may have limited an infant's ability to choose individuals other than its mother as a secure base in emergencies or during day-to-day exploration of the social and physical environment. Specifically, we will test whether: (1) individual differences in early infant-mother attachment bonds influence certain cognitive assessments and social behaviors that can be expected to be vital to an individual throughout its life-span, and (2) whether infants choose among alternative secure bases and risk-reducers or rely exclusively on their mothers for these functions. The project develops methods for measuring infants' abilities to assess risk, to choose among monkeys that might reduce risk to the infants, and to engage in exploration of the social and physical environment. These measures will be made throughout infancy and related to individual differences in secure base use to determine whether differences in secure base use predict later differences in these cognitive and social abilities. To measure individual differences in secure base use traditional ethological sampling methods will be compared with scores on a Q-sort procedure recently modified to assess secure base use in macaques and the two procedures are assessed for efficiency and reliability. The study population is the free-ranging population of rhesus macaques on Cayo Santiago, Puerto Rico. All monkeys are individually recognizable and their genealogies known; their relative ranks will be determined during the study. Our results are expected to increase understanding of the sources and significance of individual differences in secure base use. Methods developed to identify individuals that act as secure bases and to evaluate the quality of secure base use will enable us to explore whether and when individuals other than mothers serve as secure bases.
