Dr. Yitzchak Ben-Mocha

Humans’ social cognition has no equivalent in the entire animal kingdom. In spite of decades of intense research, fundamental questions remain, including (i) the selective pressures that led to the development of humans’ sophisticated social cognition, and (ii) whether humans’ cognitive capacities rely on unique cognitive mechanisms. The current debate is hindered by several shortcomings: (1) the predominant research focus on other species’ similarity to humans in terms of phylogenesis rather than in terms of their social system and (2) the paucity of research on socio-cognitive capacities in natural settings.

To contribute to the debate on the evolution of humans’ social cognition, the proposed research will investigate the hypothesis that “the presence of intensive cooperative motives influences communicative complexity”. To examine this question, I will investigate two distinct parameters crucial for human communication: reference and joint attention.
To overcome the above described shortcomings, the proposed study will systematically compare the socio-cognitive complexity of two closely related avian species which considerably differ in their cooperative motives: the long-tailed glossy starling (Lamprotornis caudatus) and the purple starling (Lamprotornis purpureus). While the first species lives in permanent social groups where all group members cooperate to raise the group’s offspring (cooperative breeding), the latter species breeds in pairs only. The study’s objectives are:

1. to document and examine the use of gestural communication in a referential way in the above species; and
2. to explicate whether and how the observed gestural communication is enabled by joint attention.

Communicative behaviors of the study species (done in the context of invitation for mating and parental care) will be video-documented, coded and compared. To allow cross species comparison, definitions and criteria for inference that were used in the study of prelinguistic human infants will be applied. We predict that, if cooperative motives have a positive influence on social cognition, sophisticated cognitive capacities such as referential and joint attentional communication will be found in the cooperative species but not necessarily in their less cooperative sister taxa.