Roots of primate cognition: the Primate Cognition Test Battery applied to three species of lemurs (Microcebus murinus, Varecia variegata and Lemur catta)

• Applicant: Dr. Claudia Fichtel
• Subject Area: Sensory and Behavioural Biology
• Term: from 2014 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 264270577

Compared to other mammals, primates, and especially humans, have relatively large brains. Since the brain is energetically very costly, the major question is which factors might have favoured the evolution of such large brains. The Primate Cognition Test Battery (PCTB) represents one systematic approach to finding answers to this central question in anthropology. It consists of a standardized and comprehensive series of cognitive experiments addressing the physical and social domain of cognitive skills. The PCTB has already been used in experiments with humans, apes and two Old World monkey species (Herrmann et al. 2007; Schmitt et al. 2012). These studies revealed that children excel all non-human primates concerning their social cognitive skills. In the physical domain, there were only minor differences across species, although they differ in relative brain size. These results suggest that social cognitive skills have had a decisive influence on brain size evolution. To test this hypothesis and to fully understand the evolution of primate and human intelligence, comparative studies of additional primate species are indicated. Strepsirrhine primates are especially suitable for such a comparative approach, since they belong to the phylogenetically ancestral primates that represent the evolutionary link to other mammals, and, hence, they can serve as living models of the ancestral cognitive skills of primates. Therefore, we will apply the PCTB to three lemur species, Microcebus murinus, Varecia variegata and Lemur catta, which exhibit variation in social organization and complexity. Furthermore, we will test the predictions of one particular hypothesis (i.e. the cooperative breeding hypothesis). It states that the level of allomaternal investment during offspring rearing has an influence on social cognitive skills. Since the three lemur species have different breeding strategies, their performances will be compared in this context. Thus, this study represents the first systematic investigation of the cognitive skills of lemurs and will provide important comparative insights into the cognitive evolution across the entire order Primates.

• DFG Programme: Research Grants