Compared to other animals, humans have evolved far more complex cultures and much greater reliance on teaching as a means of transmitting information. Scientists debate competing evolutionary explanations for these divergences, and a promising theoretical avenue emphasizes links between these traits and human life history traits: long juvenile periods and lifespans, cooperative childcare, and large relative brain size. In this project, researchers will study age-related changes in how a non-human primate species (capuchins) invents new behaviors and acquires behaviors from others in the wild. Because capuchins have independently evolved a less extreme version of the human life history pattern (e.g., slow development, long lifespans, large brains for body size, and prolonged co-residence with a variety of caregiving relatives), they can generate insights into the role of life history traits in promoting particular types of social learning. This research project will also include a number of training and science education activities. The research team will provide fieldwork opportunities and mentoring, and consequently enhanced prospects for admission to graduate school, to approximately 12 young scientists; involve high school students in data analysis; and make presentations about scientific methods and tropical forest conservation to schools near the research site. Researchers will also collaborate with videographers and with local environmental educators to produce materials to inspire students to study, appreciate, and conserve the highly endangered tropical dry forests.<br/><br/>Humans uniquely exhibit cumulative cultural evolution proposed to stem from factors including long juvenile periods that enable learning, intergenerational transmission of knowledge, cooperate care of offspring that further facilitates learning, and theory of mind. Theoretical models, and empirical work in developmental psychology, suggest that the tradeoff between trial-and-error learning and social learning, as well as the tradeoff between creativity and sticking to tried-and-true solutions, shift over the life course. However, in order to test theoretical models used to explain these findings in humans, researchers need non-human primate comparative data about the emergence and spread of new behavioral variants and the effects of population age structure on the social transmission of new ideas. Data will be collected in the Lomas Barbudal Monkey Project, now in its 30th consecutive year. Data on genetic kinship, including grandparent-grandoffspring relationships, are available for ten social groups. Focal animal behavioral sampling will focus on the oldest and youngest animals and will include (besides routine recording of social interactions and object handling) gaze monitoring, infant-alloparent communication, and instances of joint attention to objects. Group scans will document the social network structure. Data from all group members will be used to document flexibility in solving two of the most difficult foraging tasks in the behavioral repertoire, and any behavioral innovations.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.