Cognitive processes play an important role in human mate choice. However, far less is known about this topic in non-human animals. In this thesis, I take a comparative approach to sexually... Show moreCognitive processes play an important role in human mate choice. However, far less is known about this topic in non-human animals. In this thesis, I take a comparative approach to sexually selective cognition by studying humans (Homo sapiens) and Bornean orang-utans (Pongo pygmaeus). I start by reviewing the literature on sexually selective cognition. Hereafter, I show that visual, but not auditory or olfactory attractiveness, plays a major role in initial human mate choice. Furthermore, I show that attractiveness has a profound influence on visual attention in humans, and that attentional biases towards attractive conspecifics may be associated with mate choice. I explore the same topic in Bornean orang-utans by presenting them with stimuli of fully developed males or males experiencing arrested development. The results of these studies suggest that orang-utans preferentially attend to fully developed males, but only in the eye-tracking task and not in touchscreen tasks. The last chapter explores vocalisations, and suggests that orang-utan mate preferences might reflect in female vocal behaviour. Altogether, the results of this thesis suggest that humans and orang-utans show cognitive biases towards mate-relevant traits. However, better understanding of the link between such biases and actual mate choice remains of pivotal importance. Show less
What are the evolutionary roots of emotions? To answer this cardinal question, I study emotions in animals that are evolutionarily close to us: the great apes. In this dissertation, I investigated... Show moreWhat are the evolutionary roots of emotions? To answer this cardinal question, I study emotions in animals that are evolutionarily close to us: the great apes. In this dissertation, I investigated how bonobos, orangutans, and humans perceive emotions by studying three markers of emotion perception: attention, spontaneous mimicry, and implicit associations. Using touchscreen tasks and eye-tracking, I found that bonobos and humans share attentional mechanisms for perceiving their social surroundings. In both species, attention was immediately directed to emotional signals of unfamiliar others (in bonobos) or familiar others (in humans). Bonobos and humans also looked longer at certain emotionally-laden scenes than emotionally-neutral scenes. Subsequently, I studied orangutans: the only apes leading a semi-solitary existence. I found that orangutans show spontaneous mimicry in the form of contagious yawning and self-scratching, contradicting the idea that mimicry only occurs in highly social species. Finally, I created and validated a pictorial version of the implicit association test: a task that can potentially help us uncover whether apes have implicit associations with emotions. The results in this dissertation indicate a common evolutionary origin for attentional mechanisms and mimicry in great apes, including humans, and highlight the importance of considering species-specific characteristics that drive emotion perception. Show less
