Page 115 - Emotions through the eyes of our closest living relatives- Exploring attentional and behavioral mechanisms

Self-scratch contagion observed in orangutans
Introduction
Mimicry is a phenomenon in which a behavior is automatically triggered by the
perception of a similar behavior in others (Zentall, 2003). From a proximate perspective,
such contagion of behaviors can be explained by mechanisms rooted in primitive
forms of state matching and empathetic processing (Joly-Mascheroni et al., 2008;
Palagi et al., 2009). The perception‐action mechanism explains that if such behaviors
are manifestations of emotions, mimicry can result in emotional state‐matching, a
phenomenon known as emotional contagion (Preston & De Waal, 2002). However,
mimicry can also be explained more parsimoniously as the nonconscious copying of a
partner’s behavior (Massen & Gallup, 2017; Yoon & Tennie, 2010). Interestingly, forms
of mimicry are commonly found to be stronger between kin and friends (Campbell &
de Waal, 2011; Demuru & Palagi, 2012; Massen et al., 2012; Palagi et al., 2009, 2014).
Such enhanced mimicry between individuals that share social connections is thought
to facilitate group coordination and social cohesion (Clay & De Waal, 2013; Lakin et al., 5 2003; Preston & De Waal, 2002; Prochazkova & Kret, 2017).
Probably the most well‐studied behavior within the mimicry literature is yawning. While spontaneous yawning (i.e., nonsocial yawning) is widespread across vertebrates and may function in promoting cortical arousal (Baenninger, 1997; Guggisberg et al., 2010; Vick & Paukner, 2010), and/or changing emotional states through decreasing brain temperature (Gallup & Gallup, 2008; Massen et al., 2014; Massen & Gallup, 2017), contagious yawning is restricted to fewer species in which this trait may have evolved independently (Massen & Gallup, 2017).
Thus far, contagious yawning is observed in several primate species, including chimpanzees (Pan troglodytes; Anderson et al., 2004; Campbell et al., 2009; Campbell & de Waal, 2011; Massen et al., 2012), bonobos (P. paniscus; Demuru & Palagi, 2012; Palagi et al., 2014), and gelada baboons (Theropithecus gelada; E. Palagi et al., 2009). Other species in which contagious yawning is observed include domesticated dogs (Canis lupus familiaris; Joly-Mascheroni et al., 2008; Madsen & Persson, 2013), wolves (C. lupus lupus; Romero et al., 2013, 2014), budgerigars (Melopsittacus undulates; Gallup et al., 2015; Miller et al., 2012), and elephant seals (Mirounga leonina; Wojczulanis-Jakubas et al., 2019). However, some experimental studies have failed to provide convincing evidence for yawn contagion in orangutans (Pongo abelli) and gorillas (Gorilla gorilla; Amici et al., 2014), stump‐tailed macaques (Macaca arctoides; Paukner & Anderson, 2006), ring‐tailed lemurs (Lemur catta) and ruffed lemurs (Varecia variegata; Reddy et al., 2016), dogs (Harr et al., 2009), and red‐footed tortoises (Geochelone carbonaria;
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