Eleven predictions derived from the recalibrational theory of anger were tested. This theory proposes that anger is produced by a neurocognitive program engineered by natural selection to use bargaining tactics to resolve conflicts of interest in favor of the angry individual. The program is designed to orchestrate two interpersonal negotiating tactics (conditionally inflicting costs or conditionally withholding benefits) to incentivize the target of the anger to place greater weight on the welfare of the angry individual. Individuals with enhanced abilities to inflict costs (e.g., stronger individuals) or to confer benefits (e.g., attractive individuals) have a better bargaining position in conflicts; hence, it was predicted that such individuals will be more prone to anger, prevail more in conflicts of interest, and consider themselves entitled to better treatment. These predictions were confirmed. Consistent with an evolutionary analysis, the effect of strength on anger was greater for men and the effect of attractiveness on anger was greater for women. Also as predicted, stronger men had a greater history of fighting than weaker men, and more strongly endorsed the efficacy of force to resolve conflicts-both in interpersonal and international conflicts. The fact that stronger men favored greater use of military force in international conflicts provides evidence that the internal logic of the anger program reflects the ancestral payoffs characteristic of a small-scale social world rather than rational assessments of modern payoffs in large populations. aggression ͉ evolutionary psychology ͉ recalibrational theory ͉ welfare tradeoff ratio A nger is part of the basic biology of the human species. It spontaneously appears in infancy (1, 2), is effectively universal in its distribution across cultures and individuals (3, 4), and has a species-typical neural basis (5). To understand the evolutionary biology of anger, however, it is also important to characterize its evolved function-that is, what (if anything) was anger engineered by natural selection to accomplish? A recent model-the recalibrational theory of anger-hypothesizes that the regulatory program governing anger evolved in the service of bargaining, to resolve conflicts of interest in favor of the angry individual (6, 7). More precisely, the function of anger is to orchestrate behavior in the angry individual that creates incentives in the target of the anger to recalibrate upwards the weight he or she puts on the welfare of the angry individual. Here, we report empirical tests of 11 predictions derived from this model. Anger, Welfare Tradeoff Ratios (WTRs), and Bargaining. In social species, actions undertaken by one individual commonly have impacts on the welfare of others (measured in fitness, or in other currencies). Consequently, neurocognitive programs in social species should have been designed by selection to solve the following computational adaptive problem: For a given choice set involving self and other, how much weight should be placed on the welfare of the other compared with the self? We shall refer to the ratio of these weights as a welfare tradeoff ratio (WRT) between the self (i) and individual (j): WTR ij . For example, Hamilton's original model of kin-directed altruism (8) set the ratio of the weights the actor places on self vs. target to r ij , the degree of relatedness between them. Subsequent research in humans confirmed the existence of a neurocognitive specialization that recalibrates altruism in response to cues of genetic relatedness (9). As expected, its circuitry computes an internal regulatory variable, the kinship index, whose magnitude tracks r ij. When the system computes a high kinship index, it up-regulates the weight the individual places on the target's welfare relative to his or her own (that is, it increases WTR ij ). In contrast, the bargaining specialization outlined by the recalibrational model of anger computes the WTR it expects from other to self. Its function is to elicit the maximum WTR from others that it can enforce cost-effectively, given its bargaining position. This bargaining position is set by the individual's relative ability to inflict costs and to confer benefits-external variables that the cognitive architecture must internally register to regulate the individual's negotiative behavior in a fitness promoting way. Hence, instead of a kinship index, the anger system uses two different families of internal variables to regulate behavior: formidability indexes, designed to track the ability of self and others to inflict costs; and conferral indexes, designed to track the ability of self and others to confer benefits. Biologists have analyzed an array of selection pressures, in addition to kinship, that are relevant to setting WTRs, including reciprocation (10-12), aggression (13, 14) , and externalities (15). That is, these models specify strategies that conditionally trade off the welfare of the actor against the welfare of another organism (the target). If they apply to real organisms, these models implicitly require that animals have computational elements capable of implementing such strategies. Circuits are required that (i) compute the probable effect of an act on the welfare of the self, (ii) compute the probable effect of an act on the welfare of the target, and (iii) deploy a weighting function that indexes the degree to which the organism weights the welfare of the target compared with the self (i.e., a welfare tradeoff function). Although researchers often analyze kinship, aggressive formidability, reciprocity, and other such variables as single factors considered in theoretical isolation, organisms facing real choices cannot. Each act or choice is an expression of the weight the actor places on the target's welfare, and so a single act cannot express inconsistent weights at the same time. Yet diverse factors will rarely converge on the same weighting function for a specific target: a target may be a sibling, for example, yet have cheated recently in a dyadic reciprocation. To solve this adaptive problem, the brain needs machinery that registers the diverse factors that, taken individually, might call for different weightings, and integrates them into a single weighting function. That is, for those social species like humans whose members are commonly enmeshed in many divergent biological games simultaneously, the evolved neurocognitive architecture needs to be designed to integrate the welfare-relevant inputs (e.g., cues of kinship, formidability) and then generate a welfare tradeoff ratio (WTR actor, j ) as an internal regulatory variable (6, 7). This regulatory variable sets the weight the actor places on the target j's welfare relative to the actor's own welfare in its decision-making. This is necessary for the architecture to decide
REF The recalibrational theory of anger assumes that the regulatory system that directs the emotion became a means to negotiate and resolve conflicts of interest in addition to recalibrate the situation for the welfare of the subject.
Formidability and the logic of human anger.
Proceedings of the National Academy of Sciences of the United States of America
Proceedings of the National Academy of Sciences of the United States of America
Psychology Medicine