Page 130 - Demo

Chapter 6128AbstractPrimate faces provide information about a range of variant and invariant traits, including some that are relevant for mate choice. For example, faces of males may convey information about their health or genetic quality through symmetry or facial masculinity. Because perceiving and processing such information may have bearing on the reproductive success of an individual, cognitive systems are expected to be sensitive to facial cues of mate quality. However, few studies have investigated this topic in non-human primate species. Orang-utans are an ideal model species to test mate-relevant cognitive biases, because they are characterised by male bimaturism: some adult males are fully developed and bear conspicuous flanges on the side of their face, while other males look relatively similar to females. Here, we describe two non-invasive computerised experiments with Bornean orang-utans (Pongo pygmaeus), testing (i) immediate attention towards large flanges and symmetrical faces using a dot-probe task (N= 3 individuals) and (ii) choice bias for pictures of flanged males over unflanged males using a preference test (N = 6 individuals). In contrast to our expectations, we found no immediate attentional bias towards either large flanges or symmetrical faces. In addition, individuals did not show a choice bias for stimuli of flanged males. We did find exploratory evidence for a colour bias and energy efficiency trade-offs in the preference task. We discuss our null results and exploratory results in the context of the evolutionary history of Bornean orang-utans, and provide suggestions for a more biocentric approach to orang-utan cognition.Based on: Roth, T. S., Samara, I., Perea-García, J. O., & Kret, M. E. No immediate attentional bias towards or choice bias for male secondary sexual characteristics in Bornean orangutans (Pongo pygmaeus). Manuscript submitted for publication.Data availability statementThe datasets and materials generated and/or analysed during the current study are available via Dataverse: https://doi.org/10.34894/BL87ESTom Roth.indd 128 08-01-2024 10:41