Page 131 - Emotions through the eyes of our closest living relatives- Exploring attentional and behavioral mechanisms
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Evidence for yawn contagion in orangutans
Introduction
Yawning is an evolutionarily old phenomenon as its associated motor features can be
recognized in different groups of animals (Baenninger, 1987). It follows a stereotyped
pattern that, once started, is unstoppable (Provine, 1986). Apart from its spontaneous
form, it is also highly contagious, at least for some species; i.e., individuals yawn as
an unconscious and automatic response to seeing or hearing other individuals yawn
(Massen et al., 2015). While a yawning-like pattern is observed in a wide range of
vertebrates (Baenninger, 1987), contagious yawning (CY) is less wide-spread. To date,
CY appears to be present in only a few, generally social species, including tonkean
macaques (Palagi & Norscia, 2019) (and possibly stumptail macaques: Paukner &
Anderson, 2006), gelada baboons (Palagi et al., 2009), chimpanzees (Amici et al., 2014;
Anderson et al., 2004; Campbell et al., 2009; Campbell & Cox, 2019; Campbell & de
Waal, 2011, 2014; Madsen et al., 2013; Massen et al., 2012), bonobos (Demuru & Palagi,
2012; Palagi et al., 2014), dogs and wolves (Joly-Mascheroni et al., 2008; Romero et al.,
2013, 2014), sheep (Yonezawa et al., 2017), elephant seals (Wojczulanis-Jakubas et
al., 2019), budgerigars (Gallup et al., 2015), and rats (Moyaho et al., 2015). In contrast,
studies failed to show CY in grey-cheeked mangabeys and long-tailed macaques
(Deputte, 1994), mandrills (Baenninger, 1987), common marmosets (Massen et al., 6 2016), lemurs (Reddy et al., 2016), horses (Malavasi, 2014), lions (Baenninger, 1987),
tortoises (Wilkinson et al., 2011), and fish (Baenninger, 1987), even though some of these species are also very social. Despite growing interest in CY, both its proximate mechanisms (how it functions and develops) and ultimate causes (why and how it evolved) currently remain unclear.
Several hypotheses have been put forward, following a Tinbergian approach (Tinbergen, 1963). One view on the proximate mechanism underlying CY is that it is an automatic form of physiological or emotional state-matching between individuals. This synchrony of states between individuals may work via a perception–action mechanism (PAM), an adaptive mechanism that serves to create and maintain relationships in highly social species and that can give rise to higher-order cognitive phenomena such as empathy (Preston & De Waal, 2002). Some scholars argue that CY taps into the same PAM as emotion contagion (e.g., Anderson et al., 2004; Lehmann, 1979; Palagi et al., 2009; Platek et al., 2003), which is the tendency to automatically synchronize emotional states with another individual (Hatfield et al., 1993). Following this line of thought, CY can thus potentially be a proxy for empathy (i.e., the CY-empathy hypothesis) (Amici et al., 2014; Campbell & de Waal, 2011; Norscia et al.,
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