An evolutionary and developmental approach to investigating empathy: Insights from physiology and behaviour in Pan and Homo

Empathy, the sharing and understanding of others’ emotional states, is a core feature of the human social experience. Research thus far has offered promising, yet contentious, evidence of its evolutionary and developmental origins, usually based on single isolated measurements. In this thesis, I address the evolutionary and developmental origins of empathy by using a mixed-methods approach that combines naturalistic observations, behavioural experiments, and non-invasive physiological approaches to investigate behavioural markers of empathy and its potential underlying mechanisms in young human children and our closest living relatives, the great apes. The first goal of this thesis was to investigate the ontogenetic development of empathic responding in sanctuary-living bonobos. Although my findings did not support the hypothesis that more complex forms of empathy develop in tandem with other skills and/or social experiences in apes, I did identify age-specific consolatory patterns. The second goal was to investigate the link between observable empathic behaviour in ecologically valid settings with corresponding inner arousal in chimpanzees. Results suggest that arousal – as measured with facial temperature change when chimpanzees experimentally witness the distress of a conspecific - might relate to their underlying motivation to comfort distressed others. However, it remains challenging to disentangle between an arousal response related to self-distress with one of empathy. The third goal was to experimentally investigate the underlying mechanisms of empathic responding in young human children. Results confirmed a physiological reaction of children when witnessing another’s distress, which was predicted by the child’s age and sex as well as – for some measures- model familiarity. Overall, the findings shed new light on the development of empathy in both humans and our closest relatives, as well as informing on the underlying mechanisms and their relationship to external behaviour. By doing so, this comparative study advances our comprehension of the evolutionary and developmental roots of empathy.