9 Group Identification and Hormones
The amygdala has been shown to play an important role in facial recognition (Fitzgerald, Angstadt, Jelsone, Nathan, & Phan, 2006), especially when those faces display the emotion fear (LeDoux, 1996; Morris et al., 2001). Several lines of research confirm a relationship between activation of the amygdala when viewing outgroup faces (Amadio, 2003; Hart et al., 2000; Lieberman et al., 2005; Phelps et al., 2000; Wheeler & Fiske, 2005). Terbeck and colleagues (2012) were interested if reducing the activation of the amygdala would down regulate fear response that is typically shown towards outgroup members. They administered a drug that reduced the activity of the amygdala to half of their participants and a placebo to the other half. They found that participants who had received the propranolol essentially stopped displaying automatic biases towards the ingroup, thushighlighting the significant role that the amygdala plays in intergroup relations.
In terms of ingroup formations, oxytocin and endorphins have been implicated in social bonding. Tarr and colleagues (2014) found that participants who danced in synchrony during a silent disco showed evidence of greater endorphin release compared to participants who danced asynchronously during a silent disco. Endorphin release, while associated with greater bonding with the group, was not associated with greater cooperation during an economic game. De Dreu and colleagues (2010) found that their participants who were given oxytocin (a neuropeptide associated with bonding) behaved more cooperatively towards ingroup than outgroup members.
Carsten and colleagues (2011) in a series of experiments found that participants who were administered oxytocin (compared to a placebo) displayed significant increases in intergroup bias towards the ingroup. In experiments 4 and 5, Carstens et al. used 5 moral dilemnas to test for intergroup bias effects by investigating if receiving oxytocin increased the willingness to sacrifice an outgroup over an ingroup member.
The Trolley Problem
Probably the most famous moral dilemna is the trolly problem. In this problem, you are asked to imagine that you are next to a set of train tracks and next to you is a lever. A train is hurtling down the tracks and on course to strike and kill 5 people. If you were to pull the lever next to you, it will divert the train down alternate tracks and will kill one person. Do you pull the lever?
De Dreu and colleagues varied if the one person who would be killed (instead of the five) was an ingroup or outgroup member (the 5 people on the track were not given group affiliations). Participants who were administered oxytocin showed a decreased willingness to sacrifice an ingroup member to save five individuals. In the placebo condition, there was no such intergroup bias. Therefore, oxytocin seems to play a role in intergroup behaviour that tends to favour the ingroup. Stallen and colleagues (2012) found that oxytocin was associated with an increase ingroup conformity and Shalvi and colleagues (2014) found that participants who were administered oxytocin were more willing to tell a lie to benefit their ingroup. As such, associating with an ingroup and subsequent behavioural decisions (that tend to favour the ingroup) are regulated by several hormonal functions.
