Responses to the Assurance game in monkeys, apes, and humans using equivalent procedures

Abstract

There is great interest in the evolution of economic behavior. In typical studies, species are asked to play one of a series of economic games, derived from game theory, and their responses are compared. The advantage of this approach is the relative level of consistency and control that emerges from the games themselves; however, in the typical experiment, procedures and conditions differ widely, particularly between humans and other species. Thus, in the current study, we investigated how three primate species, capuchin monkeys, chimpanzees, and humans, played the Assurance (or Stag Hunt) game using procedures that were, to the best of our ability, the same across species, particularly with respect to training and pretesting. Our goal was to determine what, if any, differences existed in the ways in which these species made decisions in this game. We hypothesized differences along phylogenetic lines, which we found. However, the species were more similar than might be expected. In particular, humans who played using "nonhuman primate-friendly" rules did not behave as is typical. Thus, we find evidence for similarity in decision-making processes across the order Primates. These results indicate that such comparative studies are possible and, moreover, that in any comparison rating species' relative abilities, extreme care must be taken in ensuring that one species does not have an advantage over the others due to methodological procedures.cooperation | coordination | comparative behavior | evolution of behavior R ecent advances in the study of economic decision making have fundamentally altered how we view the science of economics. Beginning with experimental economics (1) and continuing in more recently emerging fields such as neuroeconomics (2, 3), there has been a much more scientific approach to understanding how humans make decisions in economic contexts. Most recently, there has emerged an interest in understanding the evolution of human decision making, primarily as studied using a comparative approach. Although studies of rats and pigeons emerged many decades ago, a recent surge with additional species has provided even more data relevant to social scientists interested in decision making.Although game theory has been used independently in behavioral ecology for decades (4), it is only recently that human economic games have been used extensively to address decisionmaking behavior (5, 6) and underlying neural activity (7). There are certainly reasons to think that humans and other primates might be similar in their decision-making abilities. Other primates are our closest living relatives-we share a common ancestor with chimpanzees within approximately the last 6 million y (8)-so there is a high likelihood of homology. Even though this does not mean identical decision making, it implies similarity in the underlying structures. Nonhuman primates also show many of the same cognitive skills, and even biases (9, 10), as humans. Alternately, though, humans are distinct from other primates, and even a few mil...

Emergence and suppression of cooperation by action visibility in transparent games

“…One of the main challenges in this field is extending these studies to direct real-time interactions that would entail a broad spectrum of dynamic competitive and cooperative behaviours. In line with this, several recent studies also considered direct social interactions in humans and non-human primates [3][4][5][50][51][52][53][54][55] during dyadic games where players can monitor actions and outcomes of each other. Transparent games allow modelling the players' access to social cues, which is essential for the analysis of experimental data in the studies of this kind [21].…”

To Each According to his Need? Variability in the Responses to Inequity in Non-Human Primates

“…Primates are certainly capable of using tokens to represent foods for these sorts of tasks (Addessi et al, 2007;Addessi & Rossi, 2011;Brosnan & de Waal, 2004a;Brosnan & de Waal, 2004b;Sousa & Matsuzawa, 2001). We predict diminished negative responses with tokens as compared to tasks with tangible foods, but also that individuals that have had greater experience with token tasks should show stronger responses to inequity, due to their increased experience (e.g., Brosnan et al, 2011b). In addition, it would be interesting to explore other types of biologically relevant rewards (e.g., other than foods or tokens representing foods) that might elicit the negative response to inequity.…”

Do nonhuman primates ascribe goals to the choices of conspecifics?

“…Monkeys also chose the PVC objects more than the metallic ones. Although both metal and PVC are materials the monkeys frequently encounter (their housing and enrichment is made of both materials), the PVC tokens were more similar in form to experimental tokens used routinely in our lab (e.g., Brosnan et al, 2011;Evans et al, 2012), which may explain their preference. Unfortunately, this preference for PVC could mean that their preference for certain materials overrode any preference based on their partner's choice.…”

“…One female subject often chose not to participate (i.e., did not enter the testing area on more than half of the opportunities that she had to do so) and so was dropped from testing, resulting in a sample size of 10 individuals. Prior to this study, all of our subjects had participated in studies that involved exchanging objects with an experimenter (e.g., Brosnan et al, 2011;Evans, Beran, Paglieri, & Addessi, 2012). Subjects were always housed with their social groups except when they separated voluntarily for non-invasive behavioral and cognitive testing.…”