Moralistic punishment is not for cooperation.

The theory proposed by Fitouchi et al. misses the core of puritanical morality: Cruel punishment for harmless actions. Punishment is mutually harmful, unlike cooperation which is mutually beneficial. Theories of moral judgment should not obscure this fundamental distinction.

A meta-analysis of blood glucose effects on human decision making.

The academic and public interest in blood glucose and its relationship to decision making has been increasing over the last decade. To investigate and evaluate competing theories about this relationship, we conducted a psychometric meta-analysis on the effect of blood glucose on decision making. We identified 42 studies relating to 4 dimensions of decision making: willingness to pay, willingness to work, time discounting, and decision style. We did not find a uniform influence of blood glucose on decision making. Instead, we found that low levels of blood glucose increase the willingness to pay and willingness to work when a situation is food related, but decrease willingness to pay and work in all other situations. Low levels of blood glucose increase the future discount rate for food; that is, decision makers become more impatient, and to a lesser extent increase the future discount rate for money. Low levels of blood glucose also increase the tendency to make more intuitive rather than deliberate decisions. However, this effect was only observed in situations unrelated to food. We conclude that blood glucose has domain-specific effects, influencing decision making differently depending on the relevance of the situation to acquiring food. (PsycINFO Database Record

Do men overperceive women's sexual interest?

Substantial evidence comparing men's perceptions of women's sexual intentions with women's own reports of their sexual intentions has shown a systematic pattern of results that has been interpreted as support for the idea that men overestimate women's true sexual intentions. However, because women's true sexual intentions cannot be directly measured, an alternative interpretation of the existing data is that women understate their sexual intentions and that men's assessments of women's intentions are generally accurate. In three studies, we (a) replicated the typical sex difference in sexual-intent ratings, (b) showed that men maintain their ratings of women's sexual intentions even when incentivized to tell the truth, and (c) showed that women believe that other women are understating their sexual intentions in self-report measures. Taken together, these results imply that men might be accurate in perceiving and reporting women's sexual intentions and that men might be managing errors through biased behavior rather than biased beliefs.

The evolution of altruism in humans.

Humans are an intensely social species, frequently performing costly behaviors that benefit others. Efforts to solve the evolutionary puzzle of altruism have a lengthy history, and recent years have seen many important advances across a range of disciplines. Here we bring together this interdisciplinary body of research and review the main theories that have been proposed to explain human prosociality, with an emphasis on kinship, reciprocity, indirect reciprocity, punishment, and morality. We highlight recent methodological advances that are stimulating research and point to some areas that either remain controversial or merit more attention.

Equity or equality? Moral judgments follow the money.

Previous research emphasizes people's dispositions as a source of differences in moral views. We investigate another source of moral disagreement, self-interest. In three experiments, participants played a simple economic game in which one player divides money with a partner according to the principle of equality (same payoffs) or the principle of equity (pay-offs proportional to effort expended). We find, first, that people's moral judgment of an allocation rule depends on their role in the game. People not only prefer the rule that most benefits them but also judge it to be more fair and moral. Second, we find that participants' views about equality and equity change in a matter of minutes as they learn where their interests lie. Finally, we find limits to self-interest: when the justification for equity is removed, participants no longer show strategic advocacy of the unequal division. We discuss implications for understanding moral debate and disagreement.

Covert sexual signaling: human flirtation and implications for other social species.

According to signaling theory and a large body of supporting evidence, males across many taxa produce courtship signals that honestly advertise their quality. The cost of producing or performing these signals maintains signal honesty, such that females are typically able to choose the best males by selecting those that produce the loudest, brightest, longest, or otherwise highest-intensity signals, using signal strength as a measure of quality. Set against this background, human flirting behavior, characterized by its frequent subtlety or covertness, is mysterious. Here we propose that the explanation for subtle and ambiguous signals in human courtship lies in socially imposed costs that (a) vary with social context and (b) are amplified by the unusual ways in which language makes all interactions potentially public. Flirting is a class of courtship signaling that conveys the signaler's intentions and desirability to the intended receiver while minimizing the costs that would accompany an overt courtship attempt. This proposal explains humans' taxonomically unusual courtship displays and generates a number of novel predictions for both humans and non-human social animals. Individuals who are courting should vary the intensity of their signals to suit the level of risk attached to the particular social configuration, and receivers may assess this flexible matching of signal to context as an indicator of the signaler's broader behavioral flexibility and social intelligence.

An opportunity cost model of subjective effort and task performance.

Why does performing certain tasks cause the aversive experience of mental effort and concomitant deterioration in task performance? One explanation posits a physical resource that is depleted over time. We propose an alternative explanation that centers on mental representations of the costs and benefits associated with task performance. Specifically, certain computational mechanisms, especially those associated with executive function, can be deployed for only a limited number of simultaneous tasks at any given moment. Consequently, the deployment of these computational mechanisms carries an opportunity cost--that is, the next-best use to which these systems might be put. We argue that the phenomenology of effort can be understood as the felt output of these cost/benefit computations. In turn, the subjective experience of effort motivates reduced deployment of these computational mechanisms in the service of the present task. These opportunity cost representations, then, together with other cost/benefit calculations, determine effort expended and, everything else equal, result in performance reductions. In making our case for this position, we review alternative explanations for both the phenomenology of effort associated with these tasks and for performance reductions over time. Likewise, we review the broad range of relevant empirical results from across sub-disciplines, especially psychology and neuroscience. We hope that our proposal will help to build links among the diverse fields that have been addressing similar questions from different perspectives, and we emphasize ways in which alternative models might be empirically distinguished.

Subcomponents of psychopathy have opposing correlations with punishment judgments.

Psychopathy research is plagued by an enigma: Psychopaths reliably act immorally, but they also accurately report whether an action is morally wrong. The current study revealed that cooperative suppressor effects and conflicting subsets of personality traits within the construct of psychopathy might help explain this conundrum. Among a sample of adult male offenders (N = 100) who ranked deserved punishment of crimes, Psychopathy Checklist-Revised (PCL-R) total scores were not linearly correlated with deserved punishment task performance. However, these null results masked significant opposing associations between task performance and factors of psychopathy: the PCL-R Interpersonal/Affective (i.e., manipulative and callous) factor was positively associated with task performance, while the PCL-R Social Deviance (i.e., impulsive and antisocial) factor was simultaneously negatively associated with task performance. These relationships were qualified by a significant interaction where the Interpersonal/Affective traits were positively associated with task performance when Social Deviance traits were high, but Social Deviance traits were negatively associated with task performance when Interpersonal/Affective traits were low. This interaction helped reveal a significant nonlinear relationship between PCL-R total scores and task performance such that individuals with very low or very high PCL-R total scores performed better than those with middle-range PCL-R total scores. These results may explain the enigma of why individuals with very high psychopathic traits, but not other groups of antisocial individuals, usually have normal moral judgment in laboratory settings, but still behave immorally, especially in contexts where social deviance traits have strong influence.

Individual differences in reproductive strategy are related to views about recreational drug use in Belgium, The Netherlands, and Japan.

Individual differences in moral views are often explained as the downstream effect of ideological commitments, such as political orientation and religiosity. Recent studies in the U.S. suggest that moral views about recreational drug use are also influenced by attitudes toward sex and that this relationship cannot be explained by ideological commitments. In this study, we investigate student samples from Belgium, The Netherlands, and Japan. We find that, in all samples, sexual attitudes are strongly related to views about recreational drug use, even after controlling for various ideological variables. We discuss our results in light of reproductive strategies as determinants of moral views.

Putting revenge and forgiveness in an evolutionary context.

In this response, we address eight issues concerning our proposal that human minds contain adaptations for revenge and forgiveness. Specifically, we discuss (a) the inferences that are and are not licensed by patterns of contemporary behavioral data in the context of the adaptationist approach; (b) the theoretical pitfalls of conflating proximate and ultimate causation; (c) the role of development in the production of adaptations; (d) the implications of proposing that the brain's cognitive systems are fundamentally computational in nature; (e) our preferred method for considering the role of individual differences in computational systems; (f) applications of our proposal to understanding conflicts between groups; (g) the possible implications of our views for understanding the operation of contemporary criminal justice systems; and (h) the question of whether people ever "genuinely" forgive.

Do humans really punish altruistically? A closer look.

Some researchers have proposed that natural selection has given rise in humans to one or more adaptations for altruistically punishing on behalf of other individuals who have been treated unfairly, even when the punisher has no chance of benefiting via reciprocity or benefits to kin. However, empirical support for the altruistic punishment hypothesis depends on results from experiments that are vulnerable to potentially important experimental artefacts. Here, we searched for evidence of altruistic punishment in an experiment that precluded these artefacts. In so doing, we found that victims of unfairness punished transgressors, whereas witnesses of unfairness did not. Furthermore, witnesses' emotional reactions to unfairness were characterized by envy of the unfair individual's selfish gains rather than by moralistic anger towards the unfair behaviour. In a second experiment run independently in two separate samples, we found that previous evidence for altruistic punishment plausibly resulted from affective forecasting error-that is, limitations on humans' abilities to accurately simulate how they would feel in hypothetical situations. Together, these findings suggest that the case for altruistic punishment in humans-a view that has gained increasing attention in the biological and social sciences-has been overstated.

A solution to the mysteries of morality.

We propose that moral condemnation functions to guide bystanders to choose the same side as other bystanders in disputes. Humans interact in dense social networks, and this poses a problem for bystanders when conflicts arise: which side, if any, to support. Choosing sides is a difficult strategic problem because the outcome of a conflict critically depends on which side other bystanders support. One strategy is siding with the higher status disputant, which can allow bystanders to coordinate with one another to take the same side, reducing fighting costs. However, this strategy carries the cost of empowering high-status individuals to exploit others. A second possible strategy is choosing sides based on preexisting relationships. This strategy balances power but carries another cost: Bystanders choose different sides, and this discoordination causes escalated conflicts and high fighting costs. We propose that moral cognition is designed to manage both of these problems by implementing a dynamic coordination strategy in which bystanders coordinate side-taking based on a public signal derived from disputants' actions rather than their identities. By focusing on disputants' actions, bystanders can dynamically change which individuals they support across different disputes, simultaneously solving the problems of coordination and exploitation. We apply these ideas to explain a variety of otherwise mysterious moral phenomena.

Cognitive systems for revenge and forgiveness.

Minimizing the costs that others impose upon oneself and upon those in whom one has a fitness stake, such as kin and allies, is a key adaptive problem for many organisms. Our ancestors regularly faced such adaptive problems (including homicide, bodily harm, theft, mate poaching, cuckoldry, reputational damage, sexual aggression, and the infliction of these costs on one's offspring, mates, coalition partners, or friends). One solution to this problem is to impose retaliatory costs on an aggressor so that the aggressor and other observers will lower their estimates of the net benefits to be gained from exploiting the retaliator in the future. We posit that humans have an evolved cognitive system that implements this strategy ­ deterrence ­ which we conceptualize as a revenge system. The revenge system produces a second adaptive problem: losing downstream gains from the individual on whom retaliatory costs have been imposed. We posit, consequently, a subsidiary computational system designed to restore particular relationships after cost-imposing interactions by inhibiting revenge and motivating behaviors that signal benevolence for the harmdoer. The operation of these systems depends on estimating the risk of future exploitation by the harmdoer and the expected future value of the relationship with the harmdoer. We review empirical evidence regarding the operation of these systems, discuss the causes of cultural and individual differences in their outputs, and sketch their computational architecture.

Disgust: evolved function and structure.

Interest in and research on disgust has surged over the past few decades. The field, however, still lacks a coherent theoretical framework for understanding the evolved function or functions of disgust. Here we present such a framework, emphasizing 2 levels of analysis: that of evolved function and that of information processing. Although there is widespread agreement that disgust evolved to motivate the avoidance of contact with disease-causing organisms, there is no consensus about the functions disgust serves when evoked by acts unrelated to pathogen avoidance. Here we suggest that in addition to motivating pathogen avoidance, disgust evolved to regulate decisions in the domains of mate choice and morality. For each proposed evolved function, we posit distinct information processing systems that integrate function-relevant information and account for the trade-offs required of each disgust system. By refocusing the discussion of disgust on computational mechanisms, we recast prior theorizing on disgust into a framework that can generate new lines of empirical and theoretical inquiry.

Omissions and byproducts across moral domains.

Research indicates that moral violations are judged less wrong when the violation results from omission as opposed to commission, and when the violation is a byproduct as opposed to a means to an end. Previous work examined these effects mainly for violent offenses such as killing. Here we investigate the generality of these effects across a range of moral violations including sexuality, food, property, and group loyalty. In Experiment 1, we observed omission effects in wrongness ratings for all of the twelve offenses investigated. In Experiments 2 and 3, we observed byproduct effects in wrongness ratings for seven and eight offenses (out of twelve), respectively, and we observed byproduct effects in forced-choice responses for all twelve offenses. Our results address an ongoing debate about whether different cognitive systems compute moral wrongness for different types of behaviors (surrounding violence, sexuality, food, etc.), or, alternatively, a common cognitive architecture computes wrongness for a variety of behaviors.

Artificial natural selection: can supplemental feeding domesticate mosquitoes and control mosquito-borne diseases?

A new method is proposed for controlling mosquito-borne diseases. In particular, instead of trying to kill mosquitoes, we suggest provisioning them with food from artificial feeders. Because mosquito populations are frequently limited by ecological factors other than blood meals, such as the availability of egg-laying sites, feeding mosquitoes would not necessarily increase the total number of mosquitoes, but could reduce the number of human-drawn mosquito meals. Like mosquito traps, feeders could divert biting mosquitoes away from people by means of lures, but, after diversion, prevent subsequent human bites by satiating the mosquitoes instead of killing them. Mosquito feeders might reduce the problem of the evolution of resistance to control: in an ecology with mosquito feeders, which provide safe and abundant calories for adult female mosquitoes, there could be selection for preferring (rather than avoiding) feeders, which could eventually lead to a population of feeder-preferring mosquitoes. Artificial feeders also offer the chance to introduce novel elements into the mosquito diet, such as anti- malarial or other anti-parasitic agents. Feeders might directly reduce human bites and harnesses the power of natural selection by selectively favoring feeder-preferring (rather than trap-resistant) mosquitoes.

The omission strategy.

People are more willing to bring about morally objectionable outcomes by omission than by commission. Similarly, people condemn others less harshly when a moral offense occurs by omission rather than by commission, even when intentions are controlled. We propose that these two phenomena are related, and that the reduced moral condemnation of omissions causes people to choose omissions in their own behavior to avoid punishment. We report two experiments using an economic game in which one participant (the taker) could take money from another participant (the owner) either by omission or by commission. We manipulated whether or not a third party had the opportunity to punish the taker by reducing the taker's payment. Our results indicated that the frequency of omission increases when punishment is possible. We conclude that people choose omissions to avoid condemnation and that the omission effect is best understood not as a bias, but as a strategy.