In this review, I propose a new framework for the psychological origins of human
cooperation that harnesses evolutionary theories about the two major problems posed by …

When enforcing norms for cooperative behavior, human adults sometimes exhibit in-group
bias. For example, third-party observers punish selfish behaviors committed by out-group …

Across all cultures, humans engage in cooperative activities that can be as simple as
preparing a meal or sharing food with others and as complex as playing in an orchestra or …

Egalitarian behavior is considered to be a species-typical component of human cooperation.
Human adults tend to share resources equally, even if they have the opportunity to keep a …

Cooperative behavior depends in part on a preference for equitable outcomes. Recent
research in behavioral economics assesses variables that influence adult concerns for …

Children aged 3 years and 4½ years old watched a puppet, struggling to achieve goals, who
was helped by a 2nd puppet and violently hindered by a 3rd. The children then distributed …

Merit is a key principle of fairness: rewards should be distributed according to how much
someone contributed to a task. Previous research suggests that children have an early …

The purpose of the current study was to examine the role of theory of mind in fairness-
related behavior in preschoolers and to introduce a tool for examining fairness-related …

This study investigated the motivational and social‐cognitive foundations (ie, inequality
aversion, in‐group bias, and theory of mind) that underlie the development of sharing …

Previous research has shown that the majority of 8-year-old children share valuable
resources equally with others, whereas 4-year-olds are more likely to favor themselves in …