Page 21 - Emotions through the eyes of our closest living relatives- Exploring attentional and behavioral mechanisms
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                                are provided with a window into the basic capabilities of humans and other animals 1 to process emotions.
In the last decade, interest has grown in studying contagious yawning as a form of motor mimicry (Massen et al., 2012; Miller et al., 2012b; Norscia & Palagi, 2011a). Yawning itself is a widespread behavior among vertebrates, yet it is contagious only in a limited number of social species. In addition, it has been suggested that yawn contagion is linked to emotional contagion, as contagiousness is stronger between kin and friends (Palagi et al., 2020b). At the same time, the purported link between contagious yawning and emotion contagion is heavily debated, with some researchers suggesting that the effect of social closeness on contagiousness is established not because of a fundamental emotion-sharing mechanism, but because of for instance an attentional bias to familiar individuals (Gallup, 2021; Massen & Gallup, 2017).
There are a growing number of studies showing that yawning is more contagious between strongly bonded individuals (Campbell & de Waal, 2011; Joly-Mascheroni et al., 2008; Norscia et al., 2020, 2021; Palagi et al., 2014; Romero et al., 2014), but other studies report no link with closeness (Madsen et al., 2013; Madsen & Persson, 2013; Massen et al., 2012; Neilands et al., 2020; O’Hara & Reeve, 2011), making it unclear what characteristics of social relationships (if any) modulate contagious yawning. In addition to yawning, non-facial forms of mimicry (e.g., postures, gestures) have been extensively studied in humans (see Lakin et al. (2003) for a review), but much less in animals. Self-scratch contagion – one example of non-facial mimicry – has been proposed as a candidate behavior to study the link between mimicry and emotional contagion, but work on self-scratch contagion is still limited (Feneran et al., 2013; Nakayama, 2004; Schut et al., 2015). Self-scratching can be an indicator of stress or arousal in both humans and other animals (Maestripieri et al., 1992), thus its contagiousness could potentially reveal a link with negative emotional contagion. Continued efforts to study the possible link between contagious yawning and self- scratching and emotion contagion remain important, especially for the advancement of our understanding of how animals process emotions. The second part of this dissertation (Chapters 5 and 6) will therefore center around contagious yawning and self-scratching.
Emotional modulation of implicit associations
Sensitivity to emotions can also be measured indirectly via implicit associations (Figure 1iii). To navigate the complexities of the social world, it is beneficial to form simple heuristics rather than making new social evaluations with every new situation. These
The mechanisms of emotion perception
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