Gesture development in a wild population of Sapajus libidinosus

Abstract

In the last three decades, gestures have been the focus of research on non-vocal communication in primates. The growing interest in this topic is due to its potential association with the evolution of human language. Over the years, more than 80 gestures performed by chimpanzees have been cataloged, but this type of signaling has not been extensively investigated in other taxa. In this research, I intend to identify if there are communicative gestures in a free-living population of capuchin monkeys, Sapajus libidinous, and test whether the development of this communication corroborates Fröhlich and colleagues' Social Negotiation hypothesis. This study will be conducted in three stages. Initially, I will collect data at Fazenda Boa Vista, Piauí, to observe behaviors of infants and adults that may be classified as gestures. Next, I will develop an ethogram to identify gestures, marking the direction, elaboration, or insistence of the sender and the behavioral change of the receiver. Finally, I will code data from videos in the LEDIS dataset of 10 individuals, from infancy to adulthood, and test three predictions for the Social Negotiation hypothesis: whether the repertoire of gestures increases throughout life or not, whether the use of these gestures becomes more restricted in adulthood, and whether there are gestures performed by only some individuals or if there are differences in how a gesture is executed.