Affiliation, empathy, and the origins of theory of mind

Abstract

To understand the evolution of a Theory of Mind, we need to understand the selective factors that might have jumpstarted its initial evolution. We argue that a subconscious, reflexive appreciation of others' intentions, emotions, and perspectives is at the roots of even the most complex forms of Theory of Mind and that these abilities may have evolved because natural selection has favored individuals that are motivated to empathize with others and attend to their social interactions. These skills are adaptive because they are essential to forming strong, enduring social bonds, which in turn enhance reproductive success. We first review evidence from both humans and other animals indicating that reflexive and reflective mental state attributions are inextricably linked and play a crucial role in promoting affiliative social bonds. We next describe results from free-ranging female baboons showing that individuals who show high rates of affiliative behavior form stronger social bonds with other females. These bonds, in turn, are linked to fitness. We then provide data from three different types of social challenges (male immigration, changes in grooming behavior after the death of a close relative, and responses during playback experiments), suggesting that females who manifest high rates of affiliative behavior may also be more motivated to anticipate challenges, react adaptively to setbacks, and respond appropriately to social interactions.

Keywords: personality; primates.

Fig. 1.

Percent change in females’ GC levels from 2 wk before to 2 wk after the immigration of a potentially infanticidal male. Only immigration events in which an immigrant attained the alpha rank were included in analysis. n = 33 females present for 1–3 events for a total of 64 female-events. Dashed lines indicate no change; solid lines indicate least square regression (statistics and probability values given in the text). The x axis denotes females’ scores on each of the three principle components (Aloof, Loner, and Nice) in the immigration year. Each point represents 1 female-y.

Fig. 2.

The relative number of a female’s different grooming partners in the 3 mo after the death of a close relative (mother, adult daughter, or sister) compared with the mean number of grooming partners for all other females in those months (controlled for reproductive state). n = 18 females who lost from one to three close relatives for a total sample of 24 female-y. One outlier was removed. Legend is the same as in Fig. 1.

Fig. 3.

Variation in females’ responses to playback stimuli in five different experiments (Table S1). Subjects were ranked according to the strength of their response in experimental trials minus control trials. n = 33 females in one to five experiments for a total of 73 subjects. One outlier was removed. Legend is the same as in Fig. 1.