Page 89 - Emotions through the eyes of our closest living relatives- Exploring attentional and behavioral mechanisms

Emotions hold the attention of bonobos and humans
Introduction
Emotional expressions are the conduit through which information about experiences,
desires, and intentions are communicated to others. Perceiving emotions is therefore
an adaptive process that is crucial to humans and other social animals (Ferretti
& Papaleo, 2019; Kret et al., 2020; Nieuwburg et al., 2021). In humans, emotional
information is so important that the brain prioritizes its processing even when
attentional resources are limited. There is now some evidence that this emotion-
biased attention is not only present in humans, but also in great apes (Kano et al.,
2018; Kano & Tomonaga, 2010a; Kret et al., 2016; Pritsch et al., 2017; Van Berlo et
al., 2020a). However, the manner in which great apes perceive others’ expressions of
emotions is not yet well understood. As emotions drive not only behavior, but also 4 cognitive mechanisms such as memory, learning, attention, and decision-making
(Dukes et al., 2021), examining how they are perceived and recognized by non- human animals can help us reconstruct the evolutionary history of (social) cognition in our species. Moreover, it will allow us to improve our understanding of affective states in animals. Through a comparative framework, in this paper, we investigate emotion-biased attention to emotionally salient scenes in humans as well as our closest relatives, bonobos (Pan paniscus).
The human brain is adept at selectively processing information about conspecifics (other members of the same species), and especially emotional expressions are an important source of information that can trigger selective attention (Treue, 2003). In humans, a robust body of evidence shows that emotionally salient information such as smiles or angry faces is preferentially remembered and attracts attention when attentional resources are limited (Petersen & Posner, 2012). Sensory systems are not only tuned to favor facial expressions but also whole body expressions of emotions (Kret et al., 2013a) as well as emotional scenes (Kret & Van Berlo, 2021). In general, the findings show that an attentional preference for emotionally salient information is closely tied to survival, punishment, and reward, thus likely rooted in evolutionarily old mechanisms (Öhman et al., 2001b), and likely shared with other species.
The importance of perceiving and recognizing emotional expressions is not uniquely human. In the last decade, most research efforts on the perception and recognition of emotional expressions have focused on the great apes; our closest extant relatives. Great apes express a large range of behaviors to communicate their desires and intentions to others, and primate brain circuits that are involved in the processing of social and emotional information are similar to that of humans (Hirata
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