How Strong is the Human Impulse to Cooperate?



The relationship between intuition and reflection in cooperative decision-making persists independent of social context.

Cooperation is a defining feature of human behavior, but it presents an evolutionary puzzle. How could the fundamentally selfish process of natural selection have given rise to ‘altruistic’ cooperation, which requires the individual to pay a cost for others’ benefit, and what proximate cognitive processes underlie this sort of behavior? My senior thesis is a continuation of recent work showing that people are more cooperative when making intuitive decisions than when they stop and reflect. Since this suggests that our first impulse is to be cooperative, I wanted to determine whether intuitive cooperation is context-dependent. Does the cooperative impulse persist across social situations, or can it be affected by the social context? 

I addressed these questions in two online studies, each featuring a classic economic cooperation game pitting the best outcome for the individual player against the best outcome for the group as a whole. In my first study, I set up a four-player Public Goods Game with a competitive frame that induced competitiveness among study participants. Each player received an endowment and was given the opportunity to contribute to a public fund; all money contributed was to be compounded and redistributed equally among group members. Thus, the group’s collective benefit would be maximized by contributing the full endowment, but individual payoff would be maximized by contributing nothing. My subjects were less likely to cooperate when acting under the competitive frame overall, but even in a competitive interaction, they still were more cooperative when making quick decisions than when making slower ones.

In my second study, I tested for the effects of social group allegiance using a modified Prisoner’s Dilemma. In this game, each player chooses either to cooperate with the others (acting in the interest of the group) or to defect (acting to maximize self-gain), without knowing what other players will do. In my version, subjects either played against an in-group member or an out-group member. To generate group identities, I paired up subjects according to reported 2012 presidential candidate preference and conducted the study on Election Day (November 6th, 2012). My results were analogous to the results of the first study: while subjects cooperated less in out-group interactions, faster decisions were still more cooperative than slower decisions.

My findings suggest that the relationship between intuition and reflection in cooperative decision-making persists independent of social context, implying that the cooperative impulse is a robust and definitive aspect of human behavior. The question of where this impulse comes from, however, remains unresolved. While it is likely that both social learning and evolutionary selection play a role in its development, my findings are most consistent with an evolved cooperative impulse that operates as an independent cognitive module. If this impulse were a primarily learned through life experience, subjects would have been more likely to display intuitive selfishness in competitive contexts and out-group interactions. No matter how this trait came about, however, my research has suggested that the impulse to cooperate may simply be part of what it means to be human.


The writer can be reached at