The Ash Twins Blog

Cross & Jackson (2005) demonstrate the effectiveness of heuristical decision algorithms in spiders:

Hutchinson and Gigerenzer (2005) have given us a lot to think about, and we welcome the common ground they are trying to establish between what biologists (especially ecologists) call “rules of thumb” and what psychologists call “simple heuristics”. . .

Our own research, as biologists, is based on using jumping spiders (Salticidae) to study decision making, problem solving, selective attention and other topics related to animal cognition (Cross and Jackson, in press; Harland and Jackson, 2004). Perhaps there is some common ground between understanding how simple heuristics can make us smart and understanding how salticids sometimes seem disturbingly intelligent for animals with minute brains. . .

For most web-building spiders, life may be far more predictable than for Portia, a genus of tropical salticids that single out other spiders as preferred prey (Jackson and Pollard, 1996).We might call Portia a specialist at preying on other spiders, but another spider’s web is for Portia an especially dangerous and unpredictable arena for predator-prey encounters. A spider’s web is part of its sensory system (Witt, 1975), and Portia appears to gain dynamic fine control of the other spider’s behaviour by adjusting the signals made in the web (aggressive mimicry) (Tarsitano et al., 2000). For example, many spiders may be lured in until close enough for Portia to attack, but Portia may avoid luring in long-legged pholcid spiders, choosing instead to keep the pholcid agitated and turning about in the web until there is a gap between the legs for a clear shot at the pholcid’s body (Jackson and Wilcox, 1998). . .

The male spider is what Daniel Dennett (1996) calls a Darwinian animal. It may be ‘intelligent’ in the sense of having a good solution to the problem of how long to persist in courtship, but natural selection, not the individual salticid, derived this solution. There is no need to envisage the individual male spider weighing up probabilities and doing optimality calculations.

A comparable generate-and-test algorithm (operant conditioning or trial-and-error learning) may enable individual animals to derive optimal solutions. Portia illustrates this when deriving signals by trial and error. This is what Dennett called a ‘Skinnerian animal’ . . .

Perhaps it is with Dennett’s third kind of animal (Popperian) that we begin to admire the intelligence of the individual. By running something like a simulation in its head, a Popperian animal can forego the need for real trials in the physical world. Even spiders may be Popperian. Portia, for example, routinely plans and then executes detours by which it can sneak up on other spiders from behind (Jackson et al., 2002; Tarsitano and Jackson, 1997). Although some kind of trial-and-error by simulation may underlie route choice, the particular route chosen need not first be tried out (Tarsitano and Andrew, 1999).

DeBruine (2005) writes that females prefer relatively resembling faces

Two lines of reasoning predict that women’s preferences for people exhibiting cues to kinship will be lower in the follicular phase than in the luteal phase of the menstrual cycle. Women may avoid kinship cues during the follicular phase when they are most fertile due to the costs of inbreeding. Alternatively, women may seek kinship cues during the luteal phase as a byproduct of the benefits of associating with kin during pregnancy, which is also characterized by high progesterone. We find that preferences for facial resemblance, a putative kinship cue, follow this predicted pattern and are positively correlated with estimated progesterone levels based on cycle day. Neither estimated estrogen levels nor conception risk predicted preferences for self-resemblance, and the cyclic shift was stronger for preferences for female faces than male faces. These findings lead to the possibility that this cyclic change in preference for self-resemblance may be a byproduct of a hormonal mechanism for increasing affiliative behavior toward kin during pregnancy rather than a mechanism for preventing inbreeding during fertile periods.

Source: http://www.socialbehavior.uzh.ch/teaching/semsocialneurosciencews07/DeBruine_2005_hormone_behav_self.pdf

Those individuals who never stopped playing cops and robbers will be happy to know that their bible, “Defense Tactics: Modern Arrest & Control Techniques for Today’s Police Warrior,” is a bestseller on Amazon.com. I’ll let the book speak for itself:

Whether you re a law enforcement officer wanting to improve your edge or a martial artist wanting to expand your knowledge of street proven techniques, you will find Defensive Tactics: Modern Arrest and Control Techniques for Today’s Police Warrior is filled with invaluable information including:

* Hitting with the hands, feet, forearms and elbows. . .
* Blocking an assailant’s strikes
* Using vulnerable points to gain compliance
* Head disorientation. . .
* Arresting big guys. . .

Written by a retired cop and high-ranking martial artist who survived all that the mean streets threw at him while working patrol, gang enforcement and dignitary protection, Defensive Tactics goes beyond what is taught in the academy, officer’s in-service training, and what is allowed by the administration. BONUS: Includes a chapter on proven ways to control a suspect on the ground written by LAPD officer Mark Mireles, an MMA coach, police academy trainer, and wrestling champ.

About the Author
Loren Christensen was still a rookie on probation when his police agency recruited him to teach defensive tactics to new officers hired just a few months after him. . . He borrows from these disciplines as well as other fighting arts to show you how to make your restraint, control and self-defense tactics more effective, more painful, safer for you and safer for the suspect.

Tell me if I’m wrong, but making your attacks both “more painful” and “safer for the suspect” seems to be at odds. In any case, I wouldn’t want the cop on my block to see himself as “Today’s Police Warrior.”

The ecological approach conceptualizes crime as the product of mechanistic brain machinery, inviting discussion of whether mechanistic behavioral models deprive their subjects of free will.^[1] If criminals can be reduced to animals or machines, some ask, how can we legitimately hold them responsible for their crimes? My position is that this and related questions are inappropriate for scientists and policymakers in the ecological tradition. Criminal responsibility is an empty concept that can be abandoned without subverting the criminal law’s chief theoretical and practical interest, which is the efficient deterrence of social harms. Rethinking responsibility and punishment in light of scientific principles is a desirable if not inevitable consequence of the ecological approach to crime.

As said, criminal-law traditionalists worry that the ecological approach relieves criminals of responsibility for their crimes. The answer to this objection is suggested by philosopher John Deigh,^[2] who makes an important distinction between responsibility and deterrability. For Deigh, a criminal is responsible if he physically commits a criminal act. A criminal is deterrable if the threat of punishment can prospectively prevent him from committing that act. These concepts are separable, as demonstrated by those cases of responsibility without deterrability-that is, where the actor physically performs a criminal act but the threat of punishment imposes negligible negative incentive on him. Deigh offers as examples of this category those people who are undeterrable because of mental illness and those people who are undeterrable because of political or religious fanaticism.^[3] For Deigh, there is an important distinction between these two groups: The mentally ill are relieved of responsibility for their crimes, while ideological fanatics remain criminally responsible. This distinction dovetails with our moral intuitions, but it has no implications for the criminal law. From the perspective of social welfare maximization, expending state resources to prosecute and punish an undeterrable ideologue can be as wasteful as prosecuting and punishing a person with mental illness. Assuming that the criminal law cannot deter enlistment into ideological cults in the first place, prosecution and punishment would accrue neither retrospective nor prospective benefits. Deigh’s responsibility distinction does not change this circumstance, nor does it have any implications for differences in efficient treatment between the fanatic and the mentally ill person. A rational regime would treat them identically, perhaps seeking a medicinal or psychotherapeutic cure for the mentally ill person as well as the fanatic. If no efficient preventative mechanism is feasible, the state is justified in incarcerating the fanatic as if he were mentally ill-not as punishment, but as a protective measure for the rest of society. Naturally, due process rights would still be respected, and some legal process would still be undertaken to make sure that the criminal’s claims of undeterrability are factually grounded and handled fairly. In any case, criminal responsibility plays no role in the analysis.

The aforementioned efforts to rehabilitate the fanatic rather than punish him will grate on the retributive sensibilities of many. Because the fanatic understands language and follows goal-directed behavior, he registers in our minds as an intuitive person-a moral agent. As a result, the fanatic activates our negative-reciprocity emotion mechanisms, and we feel the uncontrollable urge to take retributive action against him. That negative-reciprocity mechanism is a fitness-enhancing adaptation encoded by natural selection,[4] and it continues to motivate retributive behavior even after the criminal law has made the mechanism obsolete. Anger’s selective response to the acts of intuitive persons proved an effective strategy in primordial environments because those entities that presented person-like qualities-e.g., linguistic capacity and goal-directed behavior-were also usually deterrable by the threat of angry retribution. Intuitive personhood’s value as a proxy for sociomoral deterrability persists to this day, but the fanatic is one type of person where the heuristic fails. In consequence, the intuition persists that the fanatic deserves legal punishment despite the absence of any deterrent effect.

Assuming that the policymaker recognizes the social waste of punishing the fanatic, it is still open to question what alternative remedial measures should be taken. The ecological approach invites creative remedial solutions that transcend traditional concepts of deterrence. The general rule should be that the most efficient method to deter a social harm should be applied.

As far as general deterrence is concerned, the ecological approach benefits from a more nuanced understanding of the relationship between legal and non-legal norms. Presumably, establishment of welfare-maximizing social and moral norms is more efficient than the criminal law in deterring some crimes.^[5] Education, for instance, has been shown to significantly reduce future criminality,^[6] and the instillation of communitarian social and moral norms likely accounts for much of this reduction. Jim Heckman’s research is relevant in this regard.^[7] On this view, investing in schools might do far more to deter crime than investing in prisons.

The ecological approach’s recommendations for specific deterrence might be even more important, especially in light of recent studies indicating that incarceration does not serve a specific-deterrent function. After being in prison, these studies show, former convicts are actually deterred less from the threat of future incarceration than they were before their initial conviction.^[8] These counterintuitive and discomfiting findings constitute compelling grounds for seeking alternative and/or additional criminal remedies to imprisonment. As a starting point, criminal rehabilitation should be expanded dramatically in light of compelling empirical evidence that rehabilitative treatment results in significantly lower recidivism rates than strict incarceration.^[9] In addition, medical treatments might be expanded beyond the scope of drug addicts to other kinds of offenses, such as those related to aggression. Imprisonment imposes a negligible deterrent on the criminal with antisocial personality disorder, after all, so it might be more efficient to medicate rather than prosecute. Recent neurophysiological studies have implicated specific neurotransmitters in aggressive behavior,^[10] and drugs regulating them should not be far behind.^[11] Likewise, serial rapists and pedophiles, plagued by uncontrollable lust feelings, might agree to undergo surgical sterilization in lieu of going to prison.^[12] The superior specific deterrence afforded by these remedies weighs in favor of their replacing incarceration, notwithstanding the political controversies they would spark.

As these creative remedial reforms illustrate, the ecological approach ultimately favors a broader view of criminal policymaking that moves beyond deterrence. Perhaps the most important point to take away from this discussion is that focusing on the individual criminal as a singular moral agent ignores the bigger problem: the grave systemic maladies that spawned the criminal behavior in the first place. The investigations made by Philip Zimbardo and colleagues show that evil, rather than being the product of an individual will, is often the product of a corrupt system. Any ordinary person can be driven to foul deeds by foul ecology.^[13] In criminal trials, then, justice is never really served; the judgment preserves the systemic maladies responsible for the crime while relieving the rest of us of the responsibility for dealing with them. Because deterrence strategies are individualistic, a robust ecological approach must ultimately look beyond them.

How the law will revolutionize itself to deal with systemic malignancies is wholly unclear, but revolution is definitely the operative word. The law in general and the criminal law in particular have always been focused on individuals rather than systems, not least because the law and its instruments are organs of that system. The guiding principle should be that, in the ecological approach to the criminal law, manipulating the ecology is at least as important as manipulating the organism.

---

[1] Josuha Greene and Jonathan Cohen, “For law, neuroscience changes nothing and everything,” Philosophical Transactions of the Royal Society vol. 359 (2004), 1775-1785.

[2] John Deigh, Emotions, Values, and the Law (2008).

[3] Other conditions that might preclude deterrability include congenital disorders like schizophrenia, lesions in brain areas associated with decision-making, and environmental factors like battered women’s syndrome.

[4] Michael Price, Leda Cosmides, & John Tooby, Punitive sentiment as anti-free rider psychological device, Evolution and Human Behavior 35, 2002.

[5] Eric Posner, note 64 above, ch. 5.

[6] Lance Lochner and Enrico Moretti, “The Effect of Education on Crime: Evidence from Prison Inmates, Arrests, and Self-Reports,” The American Economic Review vol. 94 no. 1 (2004), pgs. 155-189 (estimating that “the social savings from crime reduction associated with high school graduation (for men) is about 14-26 percent of the private return”).

[7] James J. Heckman & Dmitri V. Masterov, “The Productivity Argument for Investing in Young Children,” Review of Agricultural Economics vol. 29 no. 3 (2007), pgs. 446-493.

[8] Francesco Drago, Roberto Galbiati & Pietro Vertova, “The Deterrent Effects of Prison: Evidence from a Natural Experiment,” Journal of Political Economy (forthcoming, available at http://www.econ-pol.unisi.it/~drago/).

[9] Mark W. Lipsey and Francis T. Cullen, “The Effectiveness of Correctional Rehabilitation: A Review of Systematic Reviews,” Annual Review of Law and Social Science vol. 3 (2007), (Finding that “Supervision and sanctions, at best, show modest mean reductions in recidivism and, in some instances, have the opposite effect and increase reoffense rates. The mean recidivism effects found in studies of rehabilitation treatment, by comparison, are consistently positive and relatively large.”).

[10] Thomas R. Gregg and Allan Siegel, “Brain structures and neurotransmitters regulating aggression in cats: Implications for human aggression,” Progress in neuro-psychopharmacology & biological psychiatry (2001).

[11] Extended-release intramuscular injections of psychotropic medicines have recently been developed that are effective for an entire month.  Extended-release injections of the antipsychotics haloperidol, fluphenazine, risperidone, and paliperidone are useful for uncooperative psychotic patients [Heather Dlugosz & Henry A. Nasrallah, "Paliperidone: a new extended-release oral atypical antipsychotic," Expert Opinion on Pharmacotherapy vol. 8 no. 14 (2007), pgs. 2307-2313]. Naltrexone, also available as an extended-release injection, is an opiod antagonist that blocks the pleasurable effects of morphine, heroin, and alcohol [T. K. Tucker & A.J. Ritter, "Naltrexone in the treatment of heroin dependence: a literature review," Drug and Alcohol Review vol. 19 no. 1 (2000), pgs. 73-82]. One can readily imagine similar interventions for other addictions, and even for maladaptive behaviors like impulsivity and aggression.

[12] See William Edwards and Christopher Hensley, “Restructuring Sex Offender Sentencing: A Therapeutic Jurisprudence Approach to the Criminal Justice Process,” International Journal of Offender Therapy and Comparative Criminology vol. 45 no. 6 (2001), pp. 646-662.

[13] Philip Zombardo, The Lucifer Effect (2008).

DeBruine (2004) find that both male and female subjects are more attracted to children that facially resemble themselves:

Platek et al. [Evol. Hum. Behav. 23 (2002) 159; 24 (2003) 81] reported that facial resemblance between self and a child increases professed willingness to invest in that child, and does so much more for men than for women. Because facial resemblance is a possible cue of kinship, and men, unlike women, can be mistaken about parenthood, Platek et al. predicted and interpreted this sex difference as an adaptation whereby men allocate parental investment in proportion to cues of the likelihood of paternity. Extending their approach using a more realistic technique for manipulating facial resemblance and eliminating some of the confounds in their methodology, in the current study, I found that facial resemblance increased attractiveness judgments and hypothetical investment decisions, although the published sex difference was not found. This could not be explained by differences in resemblance between the participants and the morphed images because a separate group of participants could match the original adult images to the new morphs with slightly (but not significantly) greater accuracy than to morphs made using Platek et al.’s method. In addition, composite scores indicating positive regard toward an image were correlated with resemblance as judged by independent observers.

Source: http://www.abdn.ac.uk/scl/papers/DeBruine_2004a.pdf

DeBruine (2005) finds that facial resemblance to the subject is associated with increased trust but not increased affection:

If humans are sensitive to the costs and benefits of favouring kin in different circumstances, a strong prediction is that cues of relatedness will have a positive effect on prosocial feelings, but a negative effect on sexual attraction. Indeed, positive effects of facial resemblance (a potential cue of kinship) have been demonstrated in prosocial contexts. Alternatively, such effects may be owing to a general preference for familiar stimuli. Here, I show that subtly manipulated images of other-sex faces were judged as more trustworthy by the participants they were made to resemble than by control participants. In contrast, the effects of resemblance on attractiveness were significantly lower. In the context of a long-term relationship, where both prosocial regard and sexual appeal are important criteria, facial resemblance had no effect. In the context of a short-term relationship, where sexual appeal is the dominant criterion, facial resemblance decreased attractiveness. The results provide evidence against explanations implicating a general preference for familiar-looking stimuli and suggest instead that facial resemblance is a kinship cue to which humans modulate responses in a context-sensitive manner.

Source: http://www.pubmedcentral.nih.gov/picrender.fcgi?artid=1564091&blobtype=pdf

The following reflections by economist Gordon Tullock on the differences between biology and economics perhaps explain the economics profession’s failure to predict and ward off the extant financial crisis:

Though they proceeded in some ways in parallel, there was a striking difference between the development of economics and the development of evolutionary biology. Though the biologists had various fights among themselves, and naturally made mistakes, they did not have the special problem economics does. The only real purpose of studying economics other (than intellectual amusement) is to advise governments on policy. Further, the advice is rather apt to be contrary to tradition or conventional morality. As a result, there is continuous pressure on economists to conform to the majority opinion. Further, this pressure does not come entirely from outside. Many economists themselves are upset by the teachings of their own science. It was said long ago that any economist who is any good would be unpopular. He will be offering advice which people don’t want to take. The economists may feel the same moral drives as the layman. . .

A result of this is the development of various doctrines in economics which have the characteristic of bringing policy ideas more in accord with conventional wisdom. Further, an individual biologist who finds something strikingly different normally does not have to convince a number of politicians of it before he can take advantage of it. In general, that is not true in economics. As a result of this, economics is continuously subject to pressures and fads. The two most significant examples of this in recent years were Marxism and Keynesian macroeconomics. Both of these ‘heresies’ claimed to be economic science, and indeed Keynes himself was a major economist even if his book ‘general theory of employment, interest, and money’ (1936) is more accurately described as a moral tract than as an advance in science.

As a result of this economics finds itself in a situation in which progress sometimes actually is reversed. Leading members of the profession, young graduate students, etc., will find that they are pushing hard for something which seems very much in accord with conventional wisdom, but which is, as matter of fact, contrary to the bulk of economics. . .

The end result of all this is that while biology has been steadily, if not rapidly improving, economics has a much more checkered course. It goes ahead, and then goes back. I don’t think anybody looking over the present state of economic knowledge can doubt that we know a great deal more than we did 70 years ago. It is arguable that at some times between then and now practical application of economic knowledge, which is after all the only reason we study economics, actually went into reverse.

All of these are basic problems of economics, as opposed to biology. Inflation is entirely under government control, but most governments are unwilling to admit that and try to pretend that something else causes it. As far as depressions are concerned there is a perfectly good monetary theory invented by Irving Fisher (1967). Unfortunately, it appears to be too complicated for politicians to understand, and as a consequence very unlikely to be implemented. Although this is a perfectly good theory of many depressions, it seems likely there are additional causes of depressions beyond the purely monetary mechanism that Fisher proposed. A stable currency would in fact eliminate most, but not all downturns. Further, it would make it hard for governments, as they often wish, to give the economy a temporary jolt. These temporary jolts may get the economy through the next election, but in the long run the effect is bad.

All of these are reasons why economics has difficulties. They do not affect biology. The only political difficulty that biology has is its long continuing war with substantially all of the world religions. This causes continual difficulty for various people attempting to teach biology, but has not had any serious effect on the progress of biology itself. Thus, it is quite different from the political problems confronting the economists. It is difficult to make scientific progress in an area like economics where politics is so important.

Source: http://www.springerlink.com/index/G262N873318671WG.pdf

Griskevicius et al. (2006) find that prospective artists should play the mating game:

Four experiments explored the effects of mating motivation on creativity. Even without other incentives to be creative, romantic motives enhanced creativity on subjective and objective measures. For men, any cue designed to activate a short-term or a long-term mating goal increased creative displays; however, women displayed more creativity only when primed to attract a high-quality long-term mate. These creative boosts were unrelated to increased effort on creative tasks or to changes in mood or arousal. Furthermore, results were unaffected by the application of monetary incentives for creativity. These findings align with the view that creative displays in both sexes may be linked to sexual selection, qualified by unique exigencies of human parental investment.

In a related study, Haselton & Miller (2006) find that women find creative men relatively more attractive while they are ovulating:

Male provisioning ability may have evolved as a “good dad” indicator through sexual selection, whereas male creativity may have evolved partly as a “good genes” indicator. If so, women near peak fertility (midcycle) should prefer creativity over wealth, especially in short-term mating. Forty-one normally cycling women read vignettes describing creative but poor men vs. uncreative but rich men. Women’s estimated fertility predicted their short-term (but not long-term) preference for creativity over wealth, in both their desirability ratings of individual men (r = .40, p < .01) and their forced-choice decisions between men (r = .46, p < .01). These preliminary results are consistent with the view that creativity evolved at least partly as a good genes indicator through mate choice.

Sources:

http://www.csom.umn.edu/assets/118373.pdf

http://www.unm.edu/~gfmiller/new_papers/haselton%20miller%202006%20creativecycles.pdf

Gigerenzer & Gigerenzer (2005, pg. 29) offer a valuable but oft-ignored perspective on the ultimatum game:

The behavior of people in the Ultimatum Game (UG) has been analyzed in terms of a two-person interaction between a proposer and a responder. Yet there is a third person involved: the experimenter who donates the money and has the power to withdraw it if the responder does not accept the proposer’s offer. Since the third person has no name in the theoretical analyses of the UG, let us call him or her the donor. Whether or not the donor can be treated as a neutral observer, equivalent to a measurement instrument, seems to be particularly interesting in cross-cultural comparisons. When an experimenter walks into one of the 15 small-scale societies, he or she represents a technologically advanced tribe and is likely to stand out more than when in a university lab. Both the proposer (she) and the responder (he) know that the donor will record their choices, and they might not be indifferent to the impression their behavior has on the donor. In addition, the responder may realize that by accepting he might take money away from the donor, whereas if he rejects the offer, he will give money to the donor. This three-body perspective differs from the theoretical treatment of the donor as a neutral figure, whose only task is to explain the rules and record the behavior. . .

[T]here are good reasons to consider the possibility that the behavior of the proposer is not simply a function of his expectations about the responder, or of some stable social preferences, but is also targeted at the donor. The UG is supposedly played anonymously, a term that describes the relation between proposer and responder, whereas in fact there is no anonymity between the two and the donor. In Henrich et al.’s analysis, a choice between a selfish or altruistic offer is assumed to reflect the proposer’s social preferences or expectations concerning the responder. Yet, seen as a three-body game, his or her choice could reflect her goals and expectations concerning the donor as well. A proposer might want to appear generous instead of greedy in the eyes of the donor (who is not anonymous) rather than before the responder (who is anonymous). A proposer may be embarrassed if the donor sees her offer being rejected. . .

The same holds for the responder, who can expect that the donor knows what amount he accepted or refused. A responder may also be concerned with creating a reputation of being tough by rejecting a low offer, or seeks social approval by not showing anger or disappointment in public and accepting any offer. Since he can assume he will never find out who the proposer was, and vice versa, the primary target of reputation building appears to be the donor rather than the proposer. In this view, fairness or toughness are signals towards the donor as well as the partner, unlike in two-body analyses of the UG. . .

The same perspective can be applied to the Dictator Game. The fact that a proposer offers more than zero in the Dictator game has been taken as the demonstration of genuine rather than strategic altruism. Seen as a three-body game, this conclusion does not follow. If the proposer is concerned with her reputation, an anonymous player who cannot identify her consequently cannot promote her reputation, whereas the non-anonymous donor can. . .

The three-body view of the UG extends to explanatory attempts in terms of social analogs. Such an explanation was proposed for the Orma, who recognized a similarity between the Public Goods Game and the local contributions Orma households make when the community decides to pursue a common good, such as building a school. For the UG, no such analogy was proposed, and we would be curious to learn from the authors whether they were never observed, or else, what analogies have been made. A threebody view invites looking for analogies with a richer interactive structure: one party donating goods to a second one, while retaining the option to withdraw them if the second party’s division of the pie is rejected by a third party. In such cultural analogs, if they exist, the donations could be bribes, gifts, alms, or obligations, or something else. And when the money changes hands from the donor to the proposer, it can change its functional category, such as from a gift to an obligation – but only when considered from the three-body perspective. If people can map the UG into a common analogy, then the variance in the offers (rejections) should decrease, whereas the absolute offers and acceptance levels will still vary with the specific analogy.

How would the behavior be different if the donor provided other goods to the proposer than money? If heuristics for sharing depend on the goods – meat and honey are meticulously shared among the Ache, but goods purchased by money are not (Henrich et al. 2004) – then the observed behavior in the UG should also depend on the kind of pie, not solely on some abstract preferences for selfish or altruistic behavior. In fact, in Lamalera, packs of cigarettes rather than money were used in the UG, and the Lamalera ranked among the top “altruistic” societies. Cigarettes tend to be shared, and this may enhance the appearance of a preference for altruism.

Henrich et al. assume that cultural evolution shapes preferences, yet the alternative to this view is that evolution shapes decision heuristics instead. A tit-for-tat player follows a heuristic, not a preference for altruism or defection, except in the first move. The resulting behavior is based on an interactive strategy, not on preferences that are assumed to be stable like personality traits. We think that the connection between cultural evolution and behavioral economics might be better understood as the shaping of heuristics in the adaptive toolbox. Here, the interpretation of the UG as a three-body transaction provides a new twist to the question of the influence of the environment in which the heuristics of the players are adapted. They may react to the donor as well as to the other player.

From Burnham and Kurzban’s open critique of Henrich et al (2005):

Tinbergen provided a framework that explained both maximizing behavior and persistent failures to maximize in particular settings (Tinbergen 1968), and this framework has become the standard for the study of the behavior of all animals except humans.

As an example of Tinbergen’s approach, consider work showing that herring gulls fail to maximize in environments constructed to include artificial eggs. Careful experimental studies were able to pick apart the mechanisms that gulls use for egg selection (Baerends & Drent 1982a; 1982b). These mechanisms (1) arose by natural selection, (2) advanced the inclusive fitness of the individuals in natural environments, and, crucially, (3) failed spectacularly in particular, artificial settings.

Tinbergen’s theory and its applications suggest a similar explanation for human economic behavior that fails to maximize, and this approach is already providing novel insights. For example, it has long been known that humans fail to maximize in many experimental settings involving time discounting (Ainslie 1974; Rachlin 1970). A recent study manipulated the mechanism of discounting and caused an increase or decrease in the deviation from maximization (Wilson & Daly 2004). By illuminating one aspect of the cognitive architecture behind discounting, this work suggests that the apparently puzzling economic behavior is simply caused by adaptive mechanisms interacting with particular and peculiar environments.

Similarly, a growing body of research investigates the mechanisms that modulate prosocial behavior as a function of anonymity. Models based on signaling (Smith & Bliege Bird 2000) or reputation (Panchanathan & Boyd 2003; Trivers 1971) predict the adaptive value of psychological mechanisms sensitive to cues of anonymity. Indeed, people modulate their behavior as a function of anonymity (Burnham 2003; Hoffman et al. 1996b; Rege & Telle 2004) and prosociality is more likely when actions are observed.

In fact, the data in the target article would not be surprising at all if they took place in a repeated, non-anonymous setting with an ability to generate reputations. Is this failure to maximize – like that of gulls with artificial eggs and people discounting in the laboratory – caused by mechanisms interacting with specific environmental cues? If so, it might be possible to create prosociality using cues to social presence. In particular, a powerful cue is likely to be the presence or absence of eyes, which is used to modulate behavior across many species (Call et al. 2003; Hampton 1994; Hare et al. 2001).

This hypothesis that eyes will produce prosocial economic behavior has been tested and confirmed in two studies. Contributions to a public good game increased by 29% in the presence of human eyes (Burnham & Hare, in press; see also Kurzban 2001). Similarly, contributions in a dictator game were increased 32% by the presentation of eyespots (Haley & Fessler 2005). We are optimistic that the continued application of Tinbergen’s framework to human economic decisions may provide both proximate and ultimate explanations for prosocial behavior.