The goal of this project is to measure the effects of wild capuchin monkeys' (Cebus capucinus) personality traits and early experiences on their social and reproductive success as adolescents. Although previous research on other species has documented some of these effects, no study has combined measurement of free-living young primates' personality traits, demographic circumstances (e.g. number of available same-sex playmates), kinship networks, and social development from infancy. The investigators will build on more than 6,500 hours of observation on 50 immature capuchins in and near Lomas Barbudal, Costa Rica, supplemented by over 30 field assistants' ratings of individuals on 26 hypothesized personality dimensions (e.g. impulsivity) continuously covering the entire period 2001-2006. Genetic relationships among subjects and their groupmates are already known from long-term monitoring and from analyses of DNA from fecal samples. In this project, the investigators will observe these individuals for three additional years, as females bear their first offspring and males leave their birth group and try to join another group. The researchers will test 16 hypotheses linking personality and/or early experience to various measures of adolescent success. For example, they expect that less impulsive and more extraverted males will be more likely to migrate in pairs or trios rather than alone and that co-migrating males will be more likely than lone migrants to attain high dominance rank in their group. They also predict that, compared to pre-migrant adolescent males, adolescent females' social networks will resemble their mothers' social networks more strongly. Previous findings indicate that young capuchins use complex food-processing techniques that are learned partly by observing more experienced individuals. Several hypotheses pertain to such social learning; for example, the researchers predict that individuals that reside in larger social groups and that spend more time foraging near other monkeys will attain foraging competence at an earlier age. They also hypothesize that adolescents will acquire the specific food-processing techniques employed by their close associates.
The Lomas Barbudal Monkey Project has been an important training facility for many young primatologists, offering internships usually lasting 12 months, in which the interns (typically recent university graduates) learn far more about natural history, ethological data collection, and data analysis than would be possible in a field school. In the past five years alone, 32 interns have been trained at the site. After leaving the project, these individuals have fared extremely well both on the job market and in obtaining fully funded admission to their top choice graduate programs. About two thirds of the interns have been women, and several have been members of underrepresented ethnic groups. NSF support of this proposal will provide internships to approximately 18 additional people. In addition, the project PIs and interns carry out environmental education programs within Costa Rica, focusing primarily on the elementary schools of communities adjacent to the forests where the study subjects live. The project PIs are active as consultants to the Costa Rican Wildlife Service and other local conservation agencies and are developing environmental education outreach programs.
