Chimps do not “do what the others do” merely to fit in, nor suffer for attacks against non-group members

Do Chimpanzees Conform to Social Norms? Laura Schlingloff, and Richard Moore. In The Routledge Handbook of Philosophy of Animal Minds, Jul 2017. ISBN: 978-1138822887. DOI 10.4324/9781315742250.ch36

Many studies on social influences on human behavior – including the famous Asch conformity experiments (1951) – show that we change our behavior to fit in with the crowd. [...]

To investigate whether chimpanzees copy for affiliative reasons, van Leeuwen and colleagues tested whether they abandon individually learned information in favor of a majority strategy. They found that chimpanzees do not change a first-learned strategy to conform to a majority, although they will do so to gain higher rewards (van Leeuwen et al. 2013; see also Hrubesch, Preuschoft and van Schaik 2009; and van Leeuwen and Haun 2013). This suggests that chimpanzees are not motivated to “do what the others do” merely to fit in (Leeuwen and Haun 2013).

[...] In human communities, not only do individuals prefer to conform, they also uphold the principles of their group – for example, by punishing those who do not conform. In humans, third-party enforcement of arbitrary conventional norms emerges in children as young as three years (Schmidt, Rakoczy and Tomasello 2012). Humans are also willing to suffer costs in order to sanction norm violations, even if they themselves were not harmed by the violation (Fehr and Fischbacher 2004). Currently, there is no evidence that chimpanzees enforce social norms. While they punish those who harm them directly (Jensen, Call and Tomasello 2007), this is consistent with them punishing out of revenge, and not because they think group norms should be upheld. They do not seem to engage in ‘third-party punishment’. For example, Riedl and colleagues (2012) found that chimpanzees would not retaliate against a conspecific when a third party’s food was stolen.

[...]

Apes looked longer at videos of unfamiliar individuals committing infanticidal attacks than at control videos (e.g., of chimpanzees behaving aggressively towards adults). However – with the exception of one individual who performed threat displays towards the video screen – watching infanticide did not elicit negative emotional arousal. The authors interpret the findings as showing that while chimpanzees may recognize norm violations, these violations elicit strong emotional responses only when they affect group members.