Humans are predisposed to form in-groups and out-groups that are remarkably flexible in their definition due largely to the complex language that has evolved in them. Language has allowed for the creation of shared “background stories” that can unite people who do not know each other. Second, the discovery of agriculture has resulted in the critical need to negotiate boundaries, a process that can lead to peace (but also war).

The authors make a distinction between instrumental copying behavior in which there is a clear reward for the copying behavior and social copying (traditions) in which the rewards for copying are less clear. However, I see no reason to distinguish between the two. We are social animals, for whom copying traditions have important rewards, those of affiliation.

Framing effects attributed to “quasi-cyclical” irrational complex human preferences are ubiquitous biases resulting from simpler mechanisms that can be found in other animals. Examples of such framing effects vary from simple learning contexts, to an analog of human gambling behavior, to the value added to a reinforcer by the effort that went into obtaining it.

Rachlin proposes that the mechanism underlying self-control involves the cost incurred in changing one's response pattern, but his account explains neither how the response pattern is originally established nor why a change in response pattern entails a cost. I suggest that response patterns occur because they tend to be effective (thus alternatives are more costly) and are maintained because the decision process itself is costly.

The authors' attempt to explore the ability of animals to monitor how certain they are of their choice behavior, necessarily fails both in their effort to include “higher” mammals (such as monkeys and dolphins) in the class of metacognitive organisms (humans) and in their conclusion that “lower” organisms are not capable of similar behavior.

The dance metaphor for the communication between two organisms may be an appealing image because it appears to capture the intricate synchronization of their interaction; however, it is neither parsimonious nor easily tested. Instead, a multichannel information-processing model, even one that can process only serial events, provides all of the flexibility required to account for the complex temporal coordinated action observed.

It is assumed that self-control always has a higher value. What if it does not? Furthermore, although there are clearly intrinsic reinforcers, their measurement is problematic, especially for a behavioral analyst. Finally, is it more parsimonious to postulate that these behaviors are acquired rather than genetically based?

Byrne & Russon propose that priming can account for the imitation of simple actions, but they fail to explain how the behavior of another can prime the observer's own behavior. They also propose that imitation of complex skills requires a sequence of acts tied together by a program, but they fail to rule out the role of trial-and-error learning and perceptual/motivational mechanisms in such task acquisition.

Heyes discounts findings of imitation and self recognition in nonhuman primates based on flimsy speculation and then indicates that even positive findings would not provide evidence of theory of mind. Her proposed experiment is unlikely to work, however, because, even if the animals have a theory of mind, a number of assumptions, not directly related to theory of mind, must be made about their reasoning ability.