Gowdy & Krall neglect an important aspect of human societies, which is that class systems are not genetically based but rather based on threat. In turn, threat presupposes intentionality, so seems to distinguish human from arthropod ultrasociality. Class systems, in turn, seem to explain the distinctive mixture of persistence and instability characteristic of human, but not arthropod, ultrasocial populations.

This commentary suggests (1) that there are precedents for Smaldino's “collaboration” in the history of economic thought before 1900 and (2) that the distinction of collaboration from what is thought of as cooperation in game theory is less clear than Smaldino suggests.

Bentley et al.'s scheme generates distributions characteristic of situations of high and low social influence on decisions and of high and low salience (“transparency”) of rewards. Another element of decisions that may influence the placement of a decision process in their map is the way in which individual decisions interact to determine the payoffs. This commentary discusses the role of Nash equilibria in game theory, focusing especially on coordination and anti-coordination games.

This commentary suggests that an equilibrium framework may be retained, in an evolutionary model such as Gintis's and with more satisfactory results, if rationality is relaxed in a slightly different way than he proposes: that is, if decisions are assumed to be related to rewards probabilistically, rather than with certainty. This relaxed concept of rationality gives rise to probabilistic equilibria.

While concurring that the evidence from individual differences supports a Meliorist view in the rationality debate, this commentary suggests that (1) the evidence does not clearly support a two-systems interpretation against an interpretation in terms of idiosyncratic differences in mental models, and that (2), especially where interactional processing is concerned, evidence from experimental game theory should also be considered.