One hand helps the other: development of differentiated bimanual manipulation in a non-human primate

• Grant number: 24/10298-1
• Support Opportunities: Scholarships in Brazil - Doctorate
• Effective date (Start): November 01, 2024
• Effective date (End): July 31, 2027
• Field of knowledge: Humanities - Psychology - Experimental Psychology
• Principal Investigator: Patrícia Izar Mauro
• Grantee: Guilbert Rodrigues de Araujo
• Host Institution: Instituto de Psicologia (IP). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Both humans and other primates are widely recognized for their ability to skillfully use their hands to manipulate objects. This skill is linked to development across various domains (e.g., motor and cognitive) and emerges gradually after birth. During infancy, a common pattern is the onset of unimanual actions, followed by undifferentiated bimanual actions, and later, differentiated bimanual actions, where each hand plays a different role in object manipulation. The differentiation of roles has been the subject of intense investigation in longitudinal studies with human infants; however, little is known about non-human primates, especially in their natural environments. In this study, we will investigate the development of role differentiation in the black capuchin monkey (Sapajus libidinosus), a primate species model for comparative studies. To do so, we will analyze the frequency of different bimanual actions during the first sixteen months of life in wild black capuchin monkeys inhabiting the cerrado-caatinga ecotone in the state of Piauí, northeastern Brazil. Specifically, we will test hypotheses regarding three factors that may shape the development of role differentiation: (1) frequency of bimanual actions without role differentiation, (2) properties of manipulated objects, and (3) handedness. These hypotheses have not been investigated in any other non-human primate in the wild, highlighting the novel and innovative nature of this research. The results will contribute to a better understanding of the evolution of manipulative skills that have led to the wide manual flexibility of humans, as well as elucidate factors that impact the development of bimanual coordination during infancy.