Evolutionary Origin of Empathy and Inequality Aversion

Evolutionary Origin of Empathy and Inequality Aversion. Shigeru Watanabe and Yutaka Kosaki. Evolution of the Brain, Cognition, and Emotion in Vertebrates pp 273-299, https://link.springer.com/chapter/10.1007/978-4-431-56559-8_13

Abstract: An important function of emotion is to enable individuals to adapt to the environment through induction of physiological and behavioral responses directly toward, or in anticipation of, biologically significant events such as food and predators. Another important function is to provide a social signal for other individuals in the group. This emotional signal often induces the same emotional state in the observer, a process called emotional contagion, which serves as a surrogate for others to learn through observation and provide cues to take actions in pro-social ways or, on occasions, in Machiavellian ways. Empathy, a term used to encompass these various social functions of emotion, is thus crucial for the survival of many species of animals including humans. In this chapter, we review literature concerning experimental studies of empathy in the laboratory animals, mostly rodents, which could provide a clue to understand the evolutionary origin of empathy. We first review basic findings concerning emotional contagion and introduce recent studies that examined the importance of social comparison in automatic empathetic responses, which indicate that the nonstandard forms of empathy such as envy, schadenfreude, as well as inequity aversion, may exist in rodents. We then discuss the functional significance of empathy by reviewing literature on observational learning and helping behavior. We then offer mechanistic analyses of empathy on the basis of the principles of associative learning. Finally, we discuss the evolutionary origin of social comparison.

Keywords: Emotional contagion Social comparison Envy Schadenfreude Pro-social behavior Associative learning Sexual selection