Comparative research has taught us much about the evolution and development of human and animal behavior. Humans share not just physical and biological similarities with other species, but also many behavioral traits and, in some of these cases, the psychological mechanisms behind them. Comparing behavior and cognition across multiple species can help scientists to pinpoint why and when in phylogenetic history a behavior may have evolved, how it evolved, and what the mechanisms behind it are (Tinbergen, 1963). While the comparative approach has proven quite effective in addressing these questions, comparing behavior across multiple species is not as easy and straightforward as it may initially seem. Rigorous methodology and careful interpretation of results is crucial to answering any of these questions definitively. The focus of the current article is on the comparative methodology and the important factors that need to be addressed in order for comparative research to be effective. We first discuss the benefits and importance of comparative research, followed by the challenges that need to be overcome in good comparative work. We then discuss experimental economics as one “model system” for comparative work that has proven particularly good at addressing such issues, and comment on other approaches. We conclude with future directions for comparative research with an eye on important methodological and theoretical considerations.

Comparative approaches to experimental economics have shed light on the evolution of social decision-making across a range of primate species, including humans. Here we replicate our previous work looking at six pairs of capuchin monkeys' (Sapajus [Cebus] apella) responses to scenarios requiring both coordination (Assurance Game) and anticoordination (Hawk-Dove Game). This then provides a foundation for assessing their responses to two additional games, one with a scenario of beneficial cooperation with a temptation to defect (Prisoner's Dilemma) and one with an environment requiring changing strategies within short temporal proximity (Alternating Economic Game). We additionally explored the effects of exogenous oxytocin on decision-making. Oxytocin did not affect decisions in any of our games. Results from the first two games largely replicated our previous findings. Responses to the Prisoner's Dilemma were more varied than was seen in previous games, with pairs respectively cooperating, defecting, and failing to establish stable strategies. Such variability indicates that this game may be a good assay for individual differences in social decision-making. Finally, capuchins were able to flexibly switch between their previously established strategies within each of the different games, even when the games were presented within the same session, requiring strategy adjustments within short temporal proximity. These results build on earlier findings showing that capuchins can alter decision-making strategies as the context demands, which is likely essential for decision-making in naturally occurring contexts.

Games derived from experimental economics can be used to directly compare decision-making behavior across primate species, including humans. For example, the use of coordination games, such as the Assurance game, has shown that a variety of primate species can coordinate; however, the mechanism by which they do so appears to differ across species. Recently, these games have been extended to explore anti-coordination and cooperation in monkeys, with evidence that they play the Nash equilibria in sequential games in these other contexts. In the current paper, we use the same methods to explore chimpanzees’ behavior in the Assurance Game; an anti-coordination game, the Hawk Dove game; and a cooperation game with a temptation to defect, the Prisoner’s Dilemma game. We predicted that they would consistently play the Nash equilibria, as do the monkeys, and that, as in previous work, the subjects’ level of experience with cognitive experiments would impact performance. Surprisingly, few of our pairs consistently played the same outcome (i.e., no statistically significant preferences), although those who did showed evidence consistent with Nash equilibria play, the same pattern seen more consistently in the monkeys. We consider reasons for their inconsistent performance; for instance, perhaps it was due to lack of interest in a task that rewarded them almost every trial no matter what option they chose, although this does not explain why they were inconsistent when the monkeys were not. A second goal of our study was to ascertain the effects of exogenous oxytocin in their decision making in one population. In line with recent work showing complex effects of oxytocin on social behavior, we found no effect on subjects’ outcomes. We consider possible explanations for this as well.

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This article argues that an analysis of the operations of raciality requires a description of violence whose interpretive ground is not sustained by the individual subject. By drawing on the work of Denise Ferreira da Silva, Stefano Harney, Fred Moten and others, I suggest such a description might prove a disruptive mechanism in the capacity for raciality to function as both authorizing force and the conditions of existence. In doing so, I expand on existing scholarly work that identifies manifold failings in post-enlightenment thinking and its tethering of racial subjugation to selfhood, sovereignty and agency. Moreover, I demonstrate why ethico-juridical interpretations of violence against nonwhite subjects consistently fail to identify its authorizing force, raciality.