Page 30 - Emotions through the eyes of our closest living relatives- Exploring attentional and behavioral mechanisms

Chapter 2
Abstract
Why can humans be intolerant of, yet also be empathic towards strangers? This cardinal question can be tackled by studying it in our closest living relatives, bonobos. Their striking xenophilic tendencies make them an interesting model for reconstructing the socio-emotional capacities of the last common ancestor of hominids. Within a series of dot-probe experiments, we compared bonobos’ and humans’ attention towards scenes depicting familiar (close associates and kin) or unfamiliar individuals with emotional or neutral expressions. Results show that the attention of bonobos is biased towards emotional scenes depicting unfamiliar bonobos, but not by emotional groupmates (Experiment 1) or expressions of humans, irrespective of familiarity (Experiment 2). Using a large community sample, Experiment 3 shows that human attention is biased towards emotional rather than neutral expressions of family and friends. On the one hand, our results show that an attentional bias towards emotions is a shared phenomenon between humans and bonobos, but on the other, that both species have their own unique evolutionarily informed bias. These findings support previously proposed adaptive explanations for xenophilia in bonobos which potentially biases them towards emotional expressions of unfamiliar conspecifics, and parochialism in humans, which makes them sensitive to the emotional expressions of close others.
Based on:
Van Berlo, E., Bionda, T., & Kret. M. E. (2020). Attention towards emotions is modulated by familiarity with the expressor. A comparison between bonobos and humans. Manuscript submitted for publication.
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