Darwin's evolutionary social psychology

While reading the chapter 5 of Darwin's The Descent of Man, I noticed that Darwin reconstruct Human evolutionary history as--forgive the anachronism--a gene-culture co-evolution. Of course, there was no concept of gene in Darwin's time, so the correct label would be "nature-culture co-evolution", but I was amazed to see how his intuitions are closed to current theories. Basically, he described our evolution as an evolutionary arms race (another anachronism) between social life and intelligence. The process goes trough 3 phases: social instinct, social intelligence, and social reasoning:

1. Social instincts: learning and sympathy

General intelligence

• It deserves notice that, as soon as the progenitors of man became social (and this probably occurred at a very early period), the principle of imitation, and reason, and experience would have increased, and much modified the intellectual powers in a way, of which we see only traces in the lower animals.

Social instincts: sympathy, fidelity, and courage

• In order that primeval men, or the apelike progenitors of man, should become social, they must have acquired the same instinctive feelings, which impel other animals to live in a body; and they no doubt exhibited the same general disposition. They would have felt uneasy when separated from their comrades, for whom they would have felt some degree of love; they would have warned each other of danger, and have given mutual aid in attack or defence. All this implies some degree of sympathy, fidelity, and courage.

2. Social intelligence--reciprocity and approbation

Reciprocity:

• as the reasoning powers and foresight of the members became improved, each man would soon learn that if he aided his fellow-men, he would commonly receive aid in return. From this low motive he might acquire the habit of aiding his fellows; and the habit of performing benevolent actions certainly strengthens the feeling of sympathy which gives the first impulse to benevolent actions. Habits, moreover, followed during many generations probably tend to be inherited.

Approbation

• [a] powerful stimulus to the development of the social virtues, is afforded by the praise and the blame of our fellow-men. primeval man, at a very remote period, was influenced by the praise and blame of his fellows. It is obvious, that the members of the same tribe would approve of conduct which appeared to them to be for the general good, and would reprobate that which appeared evil.

3. Social reasoning--norms, rules and morality

• With increased experience and reason, man perceives the more remote consequences of his actions, and the self-regarding virtues, such as temperance, chastity, &c., which during early times are, as we have before seen, utterly disregarded, come to be highly esteemed or even held sacred.

Evolutionary Biology and Cultural Evolution

(an update on the last post)

Mesoudi, Whiten & Laland, in their 2006 paper, furthers the analogy--already present in Boyd and Richerson--between evolutionary biology and cultural evolution:


Mesoudi, A., Whiten, A., & Laland, K. N. (2006). Towards a Unified Science of Cultural Evolution. Behav Brain Sci, 29(4), 329-347; discussion 347-383.

Dual Inheritance Theory (over)simplified

According to Dual Inheritance Theory, or Gene-Culture Coevolution, cultural evolution and cultural learning mechanisms co-evolved; our innate psychology is biased toward social learning and cultural evolution is modulated by psychological mechanisms. Culture is a population process where innovations are gradually accumulated. Cognition is geared toward imitation thanks to many biases. First, we have content biases, i.e. biases that "cause us to more readily acquire certain beliefs, ideas or behaviors because some aspect of their content makes them more appealing" (Henrich & McElreath, 2007); some food preferences (e.g., cookies) for instance may be acquired partly because we have an innate preferences for sugar. Second, we have context biases, i.e., a sensibility to exploit cues not from "things being learned" but from "individuals who are being learned from" (Ibid.,), or "models" We are sensible to successful and prestigious models and to what other people do (conformist bias). Sometimes we change our beliefs (informational conformity), and sometimes we change our behavior in order to go along with a group (normative conformity). Others like Castro & Toro (2004) suggest that the capacity to approve or disapprove their offspring's learned behavior is as important as imitation.

References

• Boyd, R., & Richerson, P. J. (1985). Culture and the Evolutionary Process. Chicago: University of Chicago Press.
• Boyd, R., & Richerson, P. J. (2005). The Origin and Evolution of Cultures Oxford: Oxford University Press.
• Castro, L., & Toro, M. A. (2004). The evolution of culture: From primate social learning to human culture. Proceedings of the National Academy of Sciences, 101(27), 10235-10240.
  
• Henrich, J. and R. McElreath (2007) Dual Inheritance Theory: The Evolution of Human Cultural Capacities and Cultural Evolution. Oxford Handbook of Evolutionary Psychology, R. Dunbar and L. Barrett, eds., Ch. 38. Oxford: Oxford Univ Press.

Evolution, cooperation and kinds of altruism

[Another clarification attempt; as ususal, comments welcome!]

Perhaps the most remarkable aspect of evolution is its ability to generate cooperation in a competitive world. Thus, we might add "natural cooperation" as a third fundamental principle of evolution beside mutation and natural selection (Nowak, 2006, p. 1563)

In a first approximation, a cooperative behavior i) benefits the recipient and ii) is beneficent or costly to the actor. Thus cooperation has two components: altruism (costly,) and mutual benefits (beneficent).

Following Sober and Wilson (1998), one may distinguishes evolutionary (or biological) altruism from psychological altruism. Psychological altruism is a psychological motivation that take another agent’s well-being (or utility) as a ultimate ends, i.e., the other agent’s well-being is “is desired for its own sake, rather than because the agent thinks that satisfying the desire will lead to the satisfaction of some other desire” (Stich, 2007, p. 268). Evolutionary altruism refers to behavior by which an organism engages in a costly behavior that benefits another organism, the cost and benefits being evaluated in terms of fitness consequences. Biologists, since Darwin, wondered why an individual would invest time and resources to help another: “He who was ready to sacrifice his life, […] rather than betray his comrades, would often leave no offspring to inherit his noble nature” (Darwin, 1871/2000, p. 130). They came up with two types of explanation: cooperation has either direct or indirect fitness consequences.

As demonstrated by Grafen, population genetics entails that natural selection favors individuals that maximize their fitness (Grafen, 1999, 2002, 2006). It does not mean that biological agents are optimal or perfect, but rather that they optimize their fitness: they tend to behave in such a way that their genes get replicated. This tendency is statistical, not teleological: on average, they do better than chance. For at least three situations (There are others, but I will discuss only the most salient in the literature), gene propagation and fitness optimization may be facilitated by others organisms and requires cooperation.

Fig. 1, based on West et al, 2007.

Cooperation can have direct or indirect fitness benefit, i.e., cooperating can contribute to one’s own survival and reproduction (direct) or it can contrbute to genetically related organisms’ survival and reproduction (indirect). Since relatives share genes with the actor, helping them is a way to maximize indirect fitness (Hamilton, 1964a, 1964b). Cooperative individuals can also maximize direct fitness if they reciprocate in repeated encounters (Trivers, 1971). A’s helping B is fitness-enhancing if A can expect B to help him in the future (direct reciprocity, or “tit-for-tat” altruism (Axelrod, 1984)). Indirect reciprocity brings a third individual: A helps B even if A never encountered B in the past because helping B contribute to building a good reputation and may result in being helped by another individual C (Nowak & Sigmund, 2005). Cooperative individuals are thus more likely to be helped (see Fig.2).

From Nowak (2006)

Direct reciprocity can be compared to “a barter economy based on the immediate exchange of goods, whereas indirect reciprocity resembles the invention of money. The money that fuels the engines of indirect reciprocity is reputation. (Nowak, 2006, p. 1561)”. Indirect reciprocity also explains evolutionary altruism as costly signaling (Zahavi & Zahavi, 1997). Evolutionarily speaking, the peacock’s tail is not the most useful body part: it makes movement difficult and is far from being discreet. However, this handicap is a costly signal since it is, for peacocks, a sign of fitness: offspring of peacocks with elaborate tails “grow and survive better under nearly natural conditions”(Petrie, 1994, p. 598). Hence the tail becomes a hard-to-fake signal directed at female peacocks. A behavior can be a costly signal if it is easily observable, costly to the actor, reliably associated with of some desirable characteristic (resources, power, skills, etc.) and lead to some evolutionary advantage such as mates, food, etc. (Smith & Bird, 2000). Costly signal theory can thus explains altruism as a behavioral costly signal: in helping unknown and unrelated individuals (when it is a perceptible and perceptibly costly behavior), the altruist individuals are in fact building social capital by hard-to-fake signals (Smith & Bird, 2004; Zahavi, 2000).

Evolutionary and psychological altruism contrast sharply. The former is a fitness-maximizing behavioral pattern whereby individuals cooperate because it promotes gene propagation and it was selected for its fitness-enhancing consequences. Biological organisms cooperate in order to maximize their inclusive fitness (the conjunction of direct and indirect fitness). Evolutionary altruisms can be found in microbes and plants as well as in birds and human (although indirect reciprocity seems to be uniquely human). Psychological altruism, most probably a capacity reserved to higher mammals or primates, is a motivation that has nothing to do with fitness (Sober & Wilson, 1998). A behavior can be evolutionary altruistic without being psychologically altruistic and vice-versa (vervet monkeys predator alarm calls). It is nonetheless possible that a psychologically altruistic behavior has fitness-enhancing consequences or that an evolutionary altruistic behavior be motivated by psychological altruism (child care for instance). One might possibly resist using the term altruism for kin discrimination, direct and indirect reciprocity, since it seems that helping another individuals so as to maximize your inclusive fitness does not sound like altruistic at all. Remember Haldane remarks, that he would give his life to save two brothers or eight cousins, since the shared genetic material is identical (quoted in McElreath & Boyd, 2007, p. 82). It seems that in the end, any kind of altruistic behavior turns out to be un-altruistic:

To extend Haldane’s famous remark, kinship can explain rescuing drowning people if they are relatives (…); reciprocal altruism if they return the favor (…); indirect reciprocity if a third party returns the favor (…) and signaling if the rescuer is judged more attractive (Farrelly et al., 2007, p. 314)

Yet if we reserve altruism solely for psychological (‘real’) altruism, it is impossible to look for an evolutionary account of altruism. “If by ‘real’ altruism we mean altruism done with the conscious intention to help, then the vast majority of living creatures are not capable of ‘real’ altruism nor therefore of ‘real’ selfishness either” (Okasha, 2005, §4).

Although psychological and evolutionary altruism are well-defined concepts they leave aside important characteristics of altruism. Take the costs and benefits, for instance. Psychological altruism, construed as a motivation, has no explicit cost or benefits. Evolutionary altruism has cost and benefits: copies of genes in the gene pool. But how can we measure whether organism X helping organism Y increases the number of X’s (or Y’s) offspring? Of course, evolutionary theory is “population thinking” (Mayr, 1959), and do not deal with single individuals in isolation. Yet, behavioral ecology (the study of animal behavior), psychology, and experimental economics do deal with individuals and need to quantify altruistic behavior. Behavioral ecologists, remark White and Crawford, “almost always ignore the number of offspring produced and study, instead, how a particular adaptation contributes to some fitness proxy, for example, net energy intake rate” (White et al., 2007, p. 276). Most of the research on cooperation deals with fitness proxies such as money, food, status: when someone donates to humanitarian organizations, it is possible to quantify how much money is donated, but not—or more difficulty—how this act increases fitness through reputation (indirect reciprocity). Similarly, cooperating in a repeated prisoner’s dilemma is direct-reciprocal, but it is not clear how it promotes genes propagation; it could be fitness-enhancing, but this is not how experimental game theory measures cooperation. Hence between evolutionary and psychological altruism I suggest we add another type of altruism: economic altruism. A behavior is economically altruistic if it benefits the recipient and it is costly to the actor; the cost and benefits are not fitness consequences, but commodities or resources (food, money, information etc.). An economically altruistic behavior could be fitness-enhancing, but need not to; it could be motivated by psychological altruism, but need not to. Economic altruism can therefore be ‘pure’ (disinterested, in which case it overlap with psychological altruism) or ‘impure” when it is motivated by a warm-glow feeling (Andreoni, 1990).

Economic altruism is therefore another category of altruistic behavior, irreducible to—but not completely independent of—psychological and biological altruism. It is the proximate, immediate, visible face of altruism and cooperation (and deeper, of morality), while evolutionary altruism is ultimate and psychological altruism is not directly observable (although neural imaging technology are now making it observable yet imprecise). Therefore, when experimental economists study how much money a subject is ready share a lab experiment, they study economic altruism (e.g. Guth & van Damme, 1998); when social psychologists study readiness to help, they study psychological altruism (e.g. Batson, 1991); and when biologists study kin recognition and nepotism in social animals, they study evolutionary altruism (e.g. Silk, 2002).

References

• Andreoni, J. (1990). Impure Altruism and Donations to Public Goods: A Theory of Warm-Glow Giving. The Economic Journal, 100(401), 464-477.
• Axelrod, R. M. (1984). The Evolution of Cooperation. New York: Basic Books.
• Batson, C. D. (1991). The Altruism Question : Toward a Social Psychological Answer. Hillsdale, N.J.: L. Erlbaum, Associates.
• Darwin, C. (1871/2000). The Descent of Man, and Selection in Relation to Sex: Adamant Media.
• Dawkins, R. (1976). The Selfish Gene. New York: Oxford University Press.
• Farrelly, D., Lazarus, J., & Roberts, G. (2007). Altruists Attract. Evolutionary Psychology, 5(2), 313-329.
• Grafen, A. (1999). Formal Darwinism, the Individual-as-Maximising-Agent Analogy, and Bet-Hedging. Proc. Roy. Soc. Ser. B, 266, 799–803.
• Grafen, A. (2002). A First Formal Link between the Price Equation and an Optimization Program. Journal of Theoretical Biology, 217(1), 75.
• Grafen, A. (2006). Optimization of Inclusive Fitness. J Theor Biol, 238(3), 541-563.
• Guth, W., & van Damme, E. (1998). Information, Strategic Behavior, and Fairness in Ultimatum Bargaining: An Experimental Study. J Math Psychol, 42(2/3), 227-247.
• Hamilton, W. D. (1964a). The Genetical Evolution of Social Behaviour. I. Journal of Theoretical Biology, 7(1), 1-16.
• Hamilton, W. D. (1964b). The Genetical Evolution of Social Behaviour. Ii. Journal of Theoretical Biology, 7(1), 17-52.
• Mayr, E. (1959). Darwin and the Evolutionary Theory in Biology. In Evolution and Anthropology: A Centennial Appraisal (pp. 409–412). Washington, D.C.: Anthropological Society of Washington.
• McElreath, R., & Boyd, R. (2007). Mathematical Models of Social Evolution : A Guide for the Perplexed. Chicago ; London: University of Chicago Press.
• Nowak, M. A. (2006). Five Rules for the Evolution of Cooperation. Science, 314(5805), 1560-1563.
• Nowak, M. A., & Sigmund, K. (2005). Evolution of Indirect Reciprocity. Nature, 437(7063), 1291-1298.
• Okasha, S. (2005). Biological Altruism. The Stanford Encyclopedia of Philosophy, Edward N. Zalta (ed.), http://plato.stanford.edu/archives/sum2005/entries/altruism-biological.
• Petrie, M. (1994). Improved Growth and Survival of Offspring of Peacocks with More Elaborate Trains. Nature, 371(6498), 598-599.
• Silk, J. B. (2002). Kin Selection in Primate Groups. International Journal of Primatology, 23(4), 849-875.
• Smith, E. A., & Bird, R. B. (2004). Costly Signaling and Cooperative Behavior. In H. Gintis, S. Bowles, R. Boyd & E. Ferh (Eds.), Moral Sentiments and Material Interests : The Foundations of Cooperation in Economic Life (pp. 115-148). Cambridge, Mass.: MIT Press.
• Smith, E. A., & Bird, R. L. B. (2000). Turtle Hunting and Tombstone Opening: Public Generosity as Costly Signaling. Evolution and Human Behavior, 21(4), 245-261.
• Sober, E., & Wilson, D. S. (1998). Unto Others : The Evolution and Psychology of Unselfish Behavior. Cambridge, Mass.: Harvard University Press.
• Stich, S. (2007). Evolution, Altruism and Cognitive Architecture: A Critique of Sober and Wilson’s Argument for Psychological Altruism. Biology and Philosophy, 22(2), 267-281.
• Trivers, R. L. (1971). The Evolution of Reciprocal Altruism. Quarterly Review of Biology, 46(1), 35.
• West, S. A., Griffin, A. S., & Gardner, A. (2007). Social Semantics: Altruism, Cooperation, Mutualism, Strong Reciprocity and Group Selection. Journal of Evolutionary Biology, 20(2), 415-432.
• White, D. W., Dill, L. M., & Crawford, C. B. (2007). A Common, Conceptual Framework for Behavioral Ecology and Evolutionary Psychology. Evolutionary Psychology,, 5(2), 275-288.
• Zahavi, A. (2000). Altruism: The Unrecognized Selfish Traits. Journal of Consciousness Studies, 7, 253-256.
• Zahavi, A., & Zahavi, A. (1997). The Handicap Principle : A Missing Piece of Darwin's Puzzle. New York: Oxford University Press.

[PNAS] Why Sex is Good, and The Evolutionary Psychology of Animate Perception

in this week PNAS:

A glimpse at the evolutionary psychology of animal perception, by New, Cosmides and Tooby (famous evolutionary psychologists):

Visual attention mechanisms are known to select information to process based on current goals, personal relevance, and lower-level features. Here we present evidence that human visual attention also includes a high-level category-specialized system that monitors animals in an ongoing manner. Exposed to alternations between complex natural scenes and duplicates with a single change (a change-detection paradigm), subjects are substantially faster and more accurate at detecting changes in animals relative to changes in all tested categories of inanimate objects, even vehicles, which they have been trained for years to monitor for sudden life-or-death changes in trajectory. This animate monitoring bias could not be accounted for by differences in lower-level visual characteristics, how interesting the target objects were, experience, or expertise, implicating mechanisms that evolved to direct attention differentially to objects by virtue of their membership in ancestrally important categories, regardless of their current utility.

• New, J., Cosmides, L., & Tooby, J. (2007). Category-specific attention for animals reflects ancestral priorities, not expertise. Proceedings of the National Academy of Sciences, 104(42), 16598-16603.
  

And the reason why sex makes people feeling good: it's all oxytocyn! Waldherr and Neumann showed that "sexual activity and mating with a receptive female reduce the level of anxiety and increase risk-taking behavior in male rats for several hours" (!) because "oxytocin is released within the brain of male rats during mating with a receptive female"

• Waldherr, M., & Neumann, I. D. (2007). Centrally released oxytocin mediates mating-induced anxiolysis in male rats. Proceedings of the National Academy of Sciences, 104(42), 16681-16684.

The Evolution of Language(s)

A lot of recent stuff on the evolution of language (the linguistic faculty) and languages ("tongues")

There is a good article in Seed Magazine ("Science is Culture"; I like their slogan !) about recent research on the evolution of language.

Language is an innate faculty, rather than a learned behavior. This idea was the primary insight of the Chomskyan revolution that helped found the field of modern linguistics in the late 1950s, and its implications are both simple and profound. If innate, language must be genetic. It is hardwired within us from conception and evolved from structures and genes with analogues existing throughout the animal kingdom. In a sense, language is universal. Yet we humans are the only species with the ability for what may rightly be called language and, moreover, we have specific linguistic behaviors that seem to have appeared only within the past 200,000 years—an eye-blink of evolution.

Why are humans the only species to have suddenly hit upon the remarkable possibilities of language? If speech is a product of our DNA, then surely other species also have some of the same genes required for language because of our basic, shared biochemistry. One of our closest relatives should have developed something that is akin to language, or another species should have happened upon its attendant advantages through parallel evolution.

See also:

• Fogassi, L., & Ferrari, P. F. (2007). Mirror Neurons and the Evolution of Embodied Language. Current Directions in Psychological Science, 16(3), 136-141.
• Kirby, S., Dowman, M., & Griffiths, T. L. (2007). Innateness and culture in the evolution of language. Proceedings of the National Academy of Sciences, 104(12), 5241.
• Pollick, A. S., & de Waal, F. B. M. (2007). Ape gestures and language evolution. Proceedings of the National Academy of Sciences, 104(19), 8184.
• Lieberman, E., Michel, J., Jackson, J., Tang, T., & Nowak, M. A. (2007). Quantifying the evolutionary dynamics of language. Nature, 449(7163), 713-716.
  
• Pagel, M., Atkinson, Q. D., & Meade, A. (2007). Frequency of word-use predicts rates of lexical evolution throughout Indo-European history. Nature, 449(7163), 717-720.
• Streaming videos on language evolution (Nature).
• Fitch, W. T. (2007). Linguistics: An invisible hand. Nature, 449(7163), 665-667. [about Lieberman et al. and Pagel et al., papers]

And Michael C. Corballis reviews two books on the motor origins of language here:

• Talking Hands: What Sign Language Reveals about the Mind. Margalit Fox. Simon and Schuster, 2007.
  
• The Gestural Origin of Language. David F. Armstrong and Sherman E. Wilcox. Oxford University Press, 2007
  

In an older article, he explains his gestural theory of language.

Review Paper on the Ultimatum, Chimps and related stuff

Thanks to Gene Expression, I found a good review paper in The Economist on the Ultimatum, Chimps and related stuff:

Evolution: Patience, fairness and the human condition. The Economist. Retrieved October 5, 2007, from

Ape-onomics: Chimps in the Ultimatum Game and Rationality in the Wild

I recently discussed the experimental study of the Ultimatum Game, and showed that it has been studied in economics, psychology, anthropology, psychophysics and genetics. Now primatologists/evolutionary anthropologists Keith Jensen, Josep Call and Michael Tomasello (the same team that showed that chimpanzees are vengeful but not spiteful see 2007a) had chimpanzees playing the Ultimatum, or more precisely, a mini-ultimatum, where proposers can make only two offers, for instance a fair vs. unfair one, or fair vs. an hyperfair, etc. Chimps had to split grapes. The possibilities were (in x/y pairs, x is the proposer, y, the responder)

• 8/2 versus 5/5
• 8/2 versus 2/8
• 8/2 versus 8/2 (no choice)
• 8/2 versus 10/0

The experimenters used the following device:

Fig. 1. (from Jensen et al, 2007b) Illustration of the testing environment. The proposer, who makes the first choice, sits to the responder's left. The apparatus, which has two sliding trays connected by a single rope, is outside of the cages. (A) By first sliding a Plexiglas panel (not shown) to access one rope end and by then pulling it, the proposer draws one of the baited trays halfway toward the two subjects. (B) The responder can then pull the attached rod, now within reach, to bring the proposed food tray to the cage mesh so that (C) both subjects can eat from their respective food dishes (clearly separated by a translucent divider)

Results indicate the chimps behave like Homo Economicus:

responders did not reject unfair offers when the proposer had the option of making a fair offer; they accepted almost all nonzero offers; and they reliably rejected only offers of zero (Jensen et al.)

As the authors conclude, "one of humans' closest living relatives behaves according to traditional economic models of self-interest, unlike humans, and t(...) does not share the human sensitivity to fairness."

So Homo Economicus would be a better picture of nature, red in tooth and claw? Yes and no. In another recent paper, Brosnan et al. studied the endowment effect in chimpanzees. The endowment effect is a bias that make us placing a higher value on objects we own relative to objects we do not. Well, chimps do that too. While they usually are indifferent between peanut butter and juice, once they "were given or ‘endowed’ with the peanut butter, almost 80 percent of them chose to keep the peanut butter, rather than exchange it for a juice bar" (from Vanderbilt news). They do not, however, have loss-aversion for non-food goods (rubber-bone dog chew toy and a knotted-rope dog toy). Another related study (Chen et al, 2006) also indicates that capuchin monkeys exhibit loss-aversion.

So there seems to be an incoherence here: chimps are both economically and non-economically rational. But this is only, as the positivists used to say, a pseudo-problem: they tend to comply with standard or 'selfish' economics in social context, but not in individual context. The difference between us and them is truly that we are, by nature, political animals. Our social rationality requires reciprocity, negotiation, exchange, communication, fairness, cooperation, morality, etc., not plain selfishness. Chimps do cooperate and exhibit a slight taste for fairness (see section 1 of this post), but not in human proportions.

Related post:

• The Ultimatum Game: Economics, Psychology, Anthroplogy, Psychophysics, Neuroscience and now, Genetics
• Altruism: A research Program.
  

Reference:

• Brosnan, S. F., Jones, O. D., Lambeth, S. P., Mareno, M. C., Richardson, A. S., Schapiro, S. J., et al. Endowment Effects in Chimpanzees. Current Biology, In Press, Corrected Proof.
• Chen, M. K., Lakshminarayanan, V., & Santos, L. (2006). How Basic Are Behavioral Biases? Evidence from Capuchin Monkey Trading Behavior. Journal of Political Economy, 114(3), 517-537.
  
• Jensen, K., Call, J., & Tomasello, M. (2007a). Chimpanzees are vengeful but not spiteful. Proceedings of the National Academy of Sciences, 0705555104.
  
• Jensen, K., Call, J., & Tomasello, M. (2007b). Chimpanzees Are Rational Maximizers in an Ultimatum Game. Science, 318(5847), 107-109.

de Waal on Altruism and Empathy

Another great paper in the 2008 Annual Review of Pyschology:

Putting the Altruism Back into Altruism: The Evolution of Empathy

Evolutionary theory postulates that altruistic behavior evolved for the return-benefits it bears the performer. For return-benefits to play a motivational role, however, they need to be experienced by the organism. Motivational analyses should restrict themselves, therefore, to the altruistic impulse and its knowable consequences. Empathy is an ideal candidate mechanism to underlie so-called directed altruism, i.e., altruism in response to anothera€™s pain, need, or distress. Evidence is accumulating that this mechanism is phylogenetically ancient, probably as old as mammals and birds. Perception of the emotional state of another automatically activates shared representations causing a matching emotional state in the observer.With increasing cognition, state-matching evolved into more complex forms, including concern for the other and perspective-taking. Empathy-induced altruism derives its strength from the emotional stake it offers the self in the othera€™s welfare. The dynamics of the empathy mechanism agree with predictions from kin selection and reciprocal altruism theory.

• Putting the Altruism Back into Altruism: The Evolution of Empathy
  Frans B.M. de Waal
  Annual Review of Psychology, January 2008, Vol. 59
  

See also, in In-Mind, a new online magazine about social cognition:

• Fairness Judgments: Genuine Morality or Disguised Egocentrism?

The Ultimatum Game: Economics, Psychology, Anthroplogy, Psychophysics, Neuroscience and now, Genetics

The Ultimatum Game (Güth et al., 1982) is a one-shot bargaining game. A first player (the Proposer) offers a fraction of a money amount; the second player (the Responder) may either accept or reject the proposal. If the Responder accepts, she keeps the offered amount while the Proposer keeps the difference. If she rejects it, both players get nothing. According to Game Theory, the subgame perfect equilibrium (a variety of Nash equilibrium for dynamic game) is the following set of strategies:

• The Proposer should offer the smallest possible amount (in order to keep as much money as possible)
• The Responder should accept any amount (because a small amount should be better than nothing)

The UG has been experimentally tested in a variety of contexts, where different parameters of the game where modified: age, sex, the amount of money, the degree of anonymity, the length of the game, etc. (Camerer & Thaler, 1995; Henrich et al., 2004; Oosterbeek et al., 2004; Samuelson, 2005). The results show a robust tendency: the game-theoretic strategy is almost never followed. People tend to anticipate and make “fair” offers. While Proposers offer about 50% of the "pie", Responders tend to accept these offers while rejecting most of the “unfair” offers (less than 20% of M). Some will even reject “too fair” offers (Bahry & Wilson, 2006)

Henrich et al (2005) studied Ultimatum behavior in 15 different small-scale societies. They found cultural variation, but these variations exhibit a constant pattern of reciprocity: differences are greater between groups than between individuals in the same group. Subjects are closer to equilibrium strategies in 4 situations: when playing against a computer, (Blount, 1995; Rilling et al., 2004; Sanfey et al., 2003; van 't Wout et al., 2006) when players are groups (Robert & Carnevale, 1997), autists (Hill & Sally, 2002) or people trained in decision and game theory, like economists and economics students (Carter & Irons, 1991; Frank et al., 1993; Kahneman et al., 1986).

Neuroeconomics shows that Ultimatum decision-making relies mainly on three areas: the anterior insula (AI), often associated with negative emotional states like disgust or anger, the dorsolateral prefrontal cortex (DLPFC), associated with cognitive control, attention, goals maintenance, and the anterior cingulate cortex (ACC), associated with cognitive conflict, motivation, error detection and emotional modulation (Sanfey et al., 2003). All three areas denote a stronger activity when the Responder faces an unfair offer. When offers are unfair, the brain faces a dilemma: punish that unfair player, or get a little money (which is better than nothing) ? The conflict involves firstly AI. This area is more active when unfair offers are proposed, and even more when the Proposer (compared to when it is a computer.) It is also correlated with the degree of unfairness (Sanfey et al., 2003: 1756) and with the decision to reject unfair offers. Skin conductance experiments show that unfair offers and their rejection are associated with greater skin conductance (van 't Wout et al., 2006). DLPFC activity remains relatively constant across unfair offers. When AI activation is greater than DLPFC, unfair offers tend to be rejected, while they tend to be accepted when DLPFC activation is greater than AI.

A new study by Wallace, Cesarini, Lichtenstein & Johannesson now investigate the influence of genes on ultimatum behavior. The compared monozigotic (same set of genes) and dizigotic ("non-identical") twins. Their statistical analysis identified which of these different factors explains the variation in behavior: genetic effects, common environmental effects, and nonshared environmental effects. They found that genetics account for 42% of the variation in responder behavior: i.e., identical twins are more likely to behave similarly in their reaction to Ultimatum proposition. Thus, sensibility to fairness might have a genetic component, an idea that proponent of the Strong Reciprocity Hypothesis put forth but did not backed with genetic studies. Yet it does not mean that that fairness preferences followed the evolutionary path advocated by SRH proponents:

Although our results are consistent with an evolutionary origin for fairness preferences, it is important to remember that heritability measures the genetically determined variation around some average behavior. Hence, it does not provide us with any direct evidence with regard to the evolutionary dynamics that brought it about (Wallace et al., p. 15633)

Of course the big question remains : how is it that genes influence the development of neural structure that control fairness preference and reciprocal behavior? A question for evo-devo-neuro-psycho-economics !

Related posts:

• More than Trust: Oxytocin Increases Generosity
• Altruism: A Research Program
• Testosterone and Ultimatum Behavior
• The Psychopath, the Prisoner's Dilemma and the Invisible Hand of Morality
  

Links:

• Wallace, B., Cesarini, D., Lichtenstein, P., & Johannesson, M. (2007). Heritability of ultimatum game responder behavior. Proceedings of the National Academy of Sciences, 0706642104. [Open Access Article]
  
  
• Genes influence people's choices in economics game (MIT news)
  Except:
  

  "Compared to common environmental influences such as upbringing, genetic influences appear to be a much more important source of variation in how people play the game," Cesarini said.
  "This raises the intriguing possibility that many of our preferences and personal economic choices are subject to substantial genetic influence," said lead author Bjorn Wallace of the Stockholm School of Economics, who conceived of the study."

  
  
  References:
  
  
  • Bahry, D. L., & Wilson, R. K. (2006). Confusion or Fairness in the Field? Rejections in the Ultimatum Game under the Strategy Method. Journal of Economic Behavior & Organization, 60(1), 37-54.
  • Blount, S. (1995). When Social Outcomes Aren't Fair: The Effect of Causal Attributions on Preferences. Organizational Behavior and Human Decision Processes, 63(2), 131-144.
  • Camerer, C., & Thaler, R. H. (1995). Anomalies: Ultimatums, Dictators and Manners. The Journal of Economic Perspectives, 9(2), 209-219.
  • Carter, J. R., & Irons, M. D. (1991). Are Economists Different, and If So, Why? The Journal of Economic Perspectives, 5(2), 171-177.
  • Frank, R. H., Gilovich, T., & Regan, D. T. (1993). Does Studying Economics Inhibit Cooperation? The Journal of Economic Perspectives, 7(2), 159-171.
  • Güth, W., Schmittberger, R., & Schwarze, B. (1982). An Experimental Analysis of Ultimatum Bargaining. Journal of Economic Behavior and Organization, 3(4), 367-388.
  • Henrich, J., Boyd, R., Bowles, S., Camerer, C., E., F., & Gintis, H. (2004). Foundations of Human Sociality: Economic Experiments and Ethnographic Evidence from Fifteen Small-Scale Societies: Oxford University Press.
  • Henrich, J., Boyd, R., Bowles, S., Camerer, C., Fehr, E., Gintis, H., McElreath, R., Alvard, M., Barr, A., Ensminger, J., Henrich, N. S., Hill, K., Gil-White, F., Gurven, M., Marlowe, F. W., Patton, J. Q., & Tracer, D. (2005). "Economic Man" In Cross-Cultural Perspective: Behavioral Experiments in 15 Small-Scale Societies. Behavioral and Brain Sciences, 28(6), 795-815; discussion 815-755.
  • Hill, E., & Sally, D. (2002). Dilemmas and Bargains: Theory of Mind, Cooperation and Fairness. working paper, University College, London.
  • Kahneman, D., Knetsch, J. L., & Thaler, R. H. (1986). Fairness and the Assumptions of Economics. The Journal of Business, 59(4), S285-S300.
  • Oosterbeek, H., S., R., & van de Kuilen, G. (2004). Differences in Ultimatum Game Experiments: Evidence from a Meta-Analysis. Experimental Economics 7, 171-188.
  • Rilling, J. K., Sanfey, A. G., Aronson, J. A., Nystrom, L. E., & Cohen, J. D. (2004). The Neural Correlates of Theory of Mind within Interpersonal Interactions. Neuroimage, 22(4), 1694-1703.
  • Robert, C., & Carnevale, P. J. (1997). Group Choice in Ultimatum Bargaining. Organizational Behavior and Human Decision Processes, 72(2), 256-279.
  • Samuelson, L. (2005). Economic Theory and Experimental Economics. Journal of Economic Literature, 43, 65-107.
  • Sanfey, A. G., Rilling, J. K., Aronson, J. A., Nystrom, L. E., & Cohen, J. D. (2003). The Neural Basis of Economic Decision-Making in the Ultimatum Game. Science, 300(5626), 1755-1758.
  • van 't Wout, M., Kahn, R. S., Sanfey, A. G., & Aleman, A. (2006). Affective State and Decision-Making in the Ultimatum Game. Exp Brain Res, 169(4), 564-568.
  • Wallace, B., Cesarini, D., Lichtenstein, P., & Johannesson, M. (2007). Heritability of ultimatum game responder behavior. Proceedings of the National Academy of Sciences, 0706642104.

My brain has a politics of its own: neuropolitic musing on values and signal detection

Political psychology (just as politicians and voters) identifies two species of political values: left/right, or liberalism/conservatism. Reviewing many studies, Thornhill & Fincher (2007) summarizes the cognitive style of both ideologies:

Liberals tend to be: against, skeptical of, or cynical about familiar and traditional ideology; open to new experiences; individualistic and uncompromising, pursuing a place in the world on personal terms; private; disobedient, even rebellious rulebreakers; sensation seekers and pleasure seekers, including in the frequency and diversity of sexual experiences; socially and economically egalitarian; and risk prone; furthermore, they value diversity, imagination, intellectualism, logic, and scientific progress. Conservatives exhibit the reverse in all these domains. Moreover, the felt need for order, structure, closure, family and national security, salvation, sexual restraint, and self-control, in general, as well as the effort devoted to avoidance of change, novelty, unpredictability, ambiguity, and complexity, is a well-established characteristic of conservatives. (Thornhill & Fincher, 2007).

In their paper, Thornhill & Fincher presents an evolutionary hypothesis for explaining the liberalism/conservatism ideologies: both originate from innate adaptation to attachement, parametrized by early childhood experiences. In another but related domain Lakoff (2002) argued that liberals and conservatives differs in their methaphors: both view the nation or the State as a child, but they hold different perspectives on how to raise her: the Strict Father model (conservatives) or the Nurturant Parent model (liberals); see an extensive description here). The first one

posits a traditional nuclear family, with the father having primary responsibility for supporting and protecting the family as well as the authority to set overall policy, to set strict rules for the behavior of children, and to enforce the rules [where] [s]elf-discipline, self-reliance, and respect for legitimate authority are the crucial things that children must learn.

while in the second:

Love, empathy, and nurturance are primary, and children become responsible, self-disciplined and self-reliant through being cared for, respected, and caring for others, both in their family and in their community.

In the October issue of Nature Neuroscience, a new research paper by Amodio et al. study the "neurocognitive correlates of liberalism and conservatism". The study is more modest than the title suggests. Subject were submitted to the same test, a Go/No Go task (click when you see a "W" don't click when it's a "M"). The experimenters then trained the subjects to be used to the Go stimuli; on a few occasions, they were presented with the No Go stimuli. Since they got used to the Go stimuli, the presentation of a No Go creates a cognitive conflict: balancing the fast/automatic/ vs. the slow/deliberative processing. You have to inhibit an habit in order to focus on the goal when the habit goes in the wrong direction. The idea was to study the correlation between political values and conflict monitoring. The latter is partly mediated by the anterior cingulate cortex, a brain area widely studied in neuroeconomics and decision neuroscience (see this post). EEG recording indicated that liberals' neural response to conflict were stronger when response inhibition was required. Hence liberalism is associated to a greater sensibility to response conflict, while conservatism is associated with a greater persistence in the habitual pattern. These results, say the authors, are

consistent with the view that political orientation, in part, reflects individual differences in the functioning of a general mechanism related to cognitive control and self-regulation

Thus valuing tradition vs. novelty, security vs. novelty might have sensorimotor counterpart, or symptoms. Of course, it does not mean that the neural basis of conservatism is identified, or the "liberal area", etc, but this study suggest how micro-tasks may help to elucidate, as the authors say in the closing sentence, "how abstract, seemingly ineffable constructs, such as ideology, are reflected in the human brain."

What this study--together with other data on conservatives and liberal--might justify is the following hypothesis: what if conservatives and liberals are natural kinds? That is, "homeostatic property clusters", (see Boyd 1991, 1999), categories of "things" formed by nature (like water, mammals, etc.), not by definition? (like supralunar objects, non-cat, grue emerald, etc.) Things that share surface properties (political beliefs and behavior) whose co-occurence can be explained by underlying mechanims (neural processing of conflict monitoring)? Maybe our evolution, as social animals, required the interplay of tradition-oriented and novelty-oriented individuals, risk-prone and risk-averse agents. But why, in the first place, evolution did not select one type over another? Here is another completely armchair hypothesis: in order to distribute, in the social body, the signal detection problem.

What kind of errors would you rather do: a false positive (you identify a signal but it's only noise) or a false negative (you think it's noise but it's a signal)? A miss or a false alarm? That is the kind of problems modeled by signal detection theory (SDT): since there is always some noise and you try to detect signal, you cannot know in advance, under radical uncertainty, what kind of policy you should stick to (risk-averse or risk-prone. "Signal" and "noise" are generic information-theoretic terms that may be related to any situation where an agent tries to find if a stimuli is present:

Is is rather ironic that signal detection theorists employ the term liberal* and conservative* (the "*" means that I am talking of SDT, not politics) to refer to different biases or criterions in signal detection. A liberal* bias is more likely to set off a positive response ( increasing the probability of false positive), whereas a conservative* bias is more likely to set off a negative response (increasing the probability of false negative). The big problem in life is that in certain domains conservatism* pay, while in others it's liberalism* who does (see Proust 2006): when identifying danger, a false negative is more expensive (better safe than sorry) whereas in looking for food a false positive can be more expensive better (better satiated than exhausted). So a robust criterion is not adaptive; but how to adjust the criterion properly? If you are an individual agent, you must altern between liberal* and conservative* criterion based on your knowledge. But if you are part of a group, liberal* and conservative* biases may be distributed: certains individuals might be more liberals* (let's send them to stand and keep watch) and other more conservatives* (let's send them foraging). Collectively, it could be a good solution (if it is enforced by norms of cooperation) to perpetual uncertainty and danger. So if our species evolved with a distribution of signal detection criterions, then we should have evolved different cognitive styles and personality traits that deal differently with uncertainty: those who favor habits, traditions, security, and the others. If liberal* and conservative* criterions are applied to other domains such as family (an institution that existed before the State), you may end up with the Strict Father model and the Nurturant Parent model; when these models are applied to political decision-making, you may end up with liberals/conservatives (no "*"). That would give a new meaning to the idea that we are, by nature, political animals.


Related posts

• A Neuropolitic Look at Political Psychology
• The Political Brain
• A Neuroecomic Picture of Valuation
  

Links

• A clear discussion of the study at The Cognitive Daily.
• Political Psychology (Blackwell Publishing Journal)
• See their special issue: Political Psychology and Social Neuroscience: Strange Bedfellows or Comrades in Arms?, especially this review paper.
• Neuropolitics.org (Ezine)
• Neuropolitics mailing list.
• A presentation of Darren Schreiber research (not professor at UCSD in the Political Science Department) on neural studies of differences between political novices and sophisticates : "When asked political questions, political novices show higher activation in the prefrontal lobes, where deliberative thinking takes place. Political sophisticates show higher levels of temporal lobe activity, which suggests they 'have more meaning attached to these questions' "

References

• Amodio, D. M., Jost, J. T., Master, S. L., & Yee, C. M. (2007). Neurocognitive correlates of liberalism and conservatism. Nature Neuroscience, 10(10), 1246-1247
• Boyd, R. (1991). Realism, Anti-Foundationalism and the Enthusiasm for Natural Kinds. Philosophical Studies, 61(1 - 2), 127.
• Boyd, R. (1999). Kinds, Complexity and Multiple Realization. Philosophical Studies, 95(1 - 2), 67.
• Lakoff, G. (2002). Moral Politics: How Liberals and Conservatives Think. Chicago: University of Chicago Press (read chapter 2 here)
• Proust, J. (2006 ). Metacognition and Animal Rationality. In S. Hurley & M. Nudds (Eds.), Rational Animals. Oxford: Oxford University Press.
  
• Thornhill, R., & Fincher, C. L. (2007). What is the relevance of attachment and life history to political values? Evolution and Human Behavior, 28(4), 215-222.
• Thorisdottir, H., Jost, J. T., Liviatan, I., & Shrout, P. E. (2007). Psychological Needs and Values Underlying Left-Right Political Orientation: Cross-National Evidence from Eastern and Western Europe. Public Opin Q, nfm008.

The Stuff of Thought

Unless you live on a desert island, you might have heard of Steven Pinker's new book, The Stuff of Thought. Language as a Window into Human Nature.

If you are interested in knowing more about it, here are an excerpt online, a book review and an interview.

Last but not least, two video lectures of Pinker at Ted Talks (an amazing collection of lecture by great scholars):

" In an exclusive preview of his new book, The Stuff of Thought, Steven Pinker looks at language, and the way it expresses the workings of our minds. By analyzing common sentences and words, he shows us how, in what we say and how we say it, we're communicating much more than we realize."





"In a preview of his next book, Steven Pinker takes on violence. We live in violent times, an era of heightened warfare, genocide and senseless crime. Or so we've come to believe. Pinker charts a history of violence from Biblical times through the present, and says modern society has a little less to feel guilty about."

Social Cognition: A Special Issue of Science

The new edition of Science if devoted to Social Cognition. It

(...) explores the adaptive advantages of group life and the accompanying development of social skills. News articles examine clues from our primate cousins about the evolution of sophisticated social behavior and explorations of human behavior made possible by computer-generated realities. Review articles dissect the human capacity for prospection and the links between sociality and brain evolution and fitness. And related podcast segments highlight research on the social abilities of children and chimps and the value of virtual worlds to studies of social science

Four papers you don't want to miss:

• Dunbar, R. I. M. and Susanne Shultz. 2007. “Evolution in the Social Brain.” Science 317(5843):1344-1347.
• Herrmann, Esther, Josep Call, Maria Victoria Hernandez-Lloreda, Brian Hare, and Michael Tomasello. 2007. “Humans Have Evolved Specialized Skills of Social Cognition: The Cultural Intelligence Hypothesis.” Science 317(5843):1360-1366.
• Silk, Joan B. 2007. “Social Components of Fitness in Primate Groups.” Science 317(5843):1347-1351.
• Wood, Justin N., David D. Glynn, Brenda C. Phillips, and Marc D. Hauser. 2007. “The Perception of Rational, Goal-Directed Action in Nonhuman Primates.” Science 317(5843):1402-1405.

Moreover, in the same edition, psychologists Dan Gilbert and Tim Wilson presents a theory of prospection, the anticipation of future events (a subject important for decision-making research:

All animals can predict the hedonic consequences of events they've experienced before. But humans can predict the hedonic consequences of events they've never experienced by simulating those events in their minds. Scientists are beginning to understand how the brain simulates future events, how it uses those simulations to predict an event's hedonic consequences, and why these predictions so often go awry.

• Gilbert, D. T., & Wilson, T. D. (2007). Prospection: Experiencing the Future. Science, 317(5843), 1351-1354.

On self-control -- an update

I discussed a recent experiment on self-control and its possible neural basis (dorsal fronto-median cortex (dFMC)) last week; The story is also covered in the new edition of Science NOW; interestingly, the same issue also presents another study about self-control, but this time in chimps: they use self-distraction in order to resist temptation. A clear case, I think, of genuine metacognition in our closest cousins.

Psychologists Theodore Evans and Michael Beran put each of four chimps in front of a container connected to a candy dispenser. The chimps could reach over and pick up the container to eat the accumulated candies at any time, but doing so stopped the dispenser from delivering any more. That allowed the chimps to delay the reward as long as they wanted--so that they could get more of it.

In another experiment, the chimps were presented with the same scenario but also given some toys. Just like fidgety children, the chimps were able to hold out longer in this situation by distracting themselves with toys, the team reports online today in Biology Letters. To test whether playing with the toys was indeed a distraction technique, the researchers set up yet another condition in which the chimps could see the candy container filling up but couldn't reach it. Most of the chimps spent significantly more time playing with the toys when they could access the container than when they could not, indicating that their play was a deliberate strategy to control the impulse to eat the candies.

Read the paper in Biology Letters:

• Evans, T. A., & Beran, M. J. (in press). Chimpanzees use self-distraction to cope with impulsivity. Biology Letters.

Biology of Societies: A Special Issue of Current Biology

Recommended reading for anybody interested in social cognition, sociality, and biology: The last issue of Current Biology is devoted to the Biology of Societies:

• Frank, S. A. (2007). All of life is social. Current Biology, 17(16), R648-R650.
• Jackson, D. E. (2007). Social spiders. Current Biology, 17(16), R650-R652.
• Clayton, N. S., & Emery, N. J. (2007). The social life of corvids. Current Biology, 17(16), R652-R656.
• Watts, H. E., & Holekamp, K. E. (2007). Hyena societies. Current Biology, 17(16), R657-R660.
• West, S. A., Griffin, A. S., & Gardner, A. (2007). Evolutionary Explanations for Cooperation. Current Biology, 17(16), R661-R672.
• Boomsma, J. J. (2007). Kin Selection versus Sexual Selection: Why the Ends Do Not Meet. Current Biology, 17(16), R673-R683.
• Shaulsky, G., & Kessin, R. H. (2007). The Cold War of the Social Amoebae. Current Biology, 17(16), R684-R692.
• Cremer, S., Armitage, S. A. O., & Schmid-Hempel, P. (2007). Social Immunity. Current Biology, 17(16), R693-R702.
• Leadbeater, E., & Chittka, L. (2007). Social Learning in Insects -- From Miniature Brains to Consensus Building. Current Biology, 17(16), R703-R713.
• Byrne, R. W., & Bates, L. A. (2007). Sociality, Evolution and Cognition. Current Biology, 17(16), R714-R723.
• Frith, C. D., & Frith, U. (2007). Social Cognition in Humans. Current Biology, 17(16), R724-R732.

The Economy of Nature: A Brief Introduction

all organic beings are striving to seize on each place in the economy of nature

(Darwin, [1859] 2003, p. 90)

Needless to say, Darwin’s theory of descent with modification was a true conceptual revolution[1]. It provides a general mechanism that explains the diversity and adaptivity of living beings—natural selection—and a guiding principle for organizing the mass of facts about them, the tree of life [2]. In recalling how this idea had come to his mind, Darwin wrote that he was trying to solve one problem: how is it that plants and animals sharing a common ancestry end up to be so different?

“The solution, as I believe, is that the modified offspring of all dominant and increasing forms tend to become adapted to many and highly diversified places in the economy of nature”[3].

Darwin repeatedly uses the expression “economy of nature” in The Origin of Species and other writings. He was not the first to conceive nature as an economy, although he was among the first to suggest an explicit similarity between natural and political economy. Before Darwin, the idea of nature as an economy had no particular ramification with human economic practices. In The Sacred Theory of the Earth, theologian Thomas Burnet referred to the “Oeconomy of nature” as the “well ordering of the great Family of living Creatures”[4] an order of divine origin. Swedish naturalist Carl Linnaeus, in his Specimen Academicum de Oeconomia Naturae, construed this divine order has being self-organized, exhibiting a balance of births and deaths, a complementarity between the function and purpose of life forms[5]. Adam Smith recognized the unity of this economy, where all living forms strive for “self-preservation, and the propagation of the species” but are limited in their problem-solving capacities, and hence must often rely on intuition instead of reasoning[6]. Lyell, in his Principle of Geology, describes how the involuntary agency of human and other animals “

contribute to extend or limit the geographical range and numbers of certain species, in obedience to general rules in the economy of nature, which are for most the part out of our control”[7].

Where Linnaeus saw a clockwork organization, Lyell’s representation of the world was more that of a dynamic equilibrium.

Thus, from natural theology to geology, the economy of nature referred to the complex organization of the universe[8]. What was new with Darwin is that the economy of nature began to be understood with conceptual tools borrowed from political economy. The division of labor, competition (“struggle” in Darwin’s words), trading, cost, the accumulation of innovations, the emergence of complex order from unintentional individual actions, the scarcity of resources and the geometric growth of populations are ideas borrowed from Adam Smith, Thomas Malthus, David Hume and other founders of modern economics. Thus, the “economy of nature” ceased to be an abstract representation of the universe and became a depiction of the complex web of interactions between biological individuals, species and their environment. The beginning of evolutionary biology coincided also with the beginning of ecology. The founder of ecology, Ernst Haeckel, defined this science as

“the body of knowledge concerning the economy of nature (…) the study of all those complex interrelationships referred to by Darwin as the condition of the struggle for existence”[9].

Consequently, Darwin’s main contributions are its transforming biology into a historical science (like geology) and an economic science[10]. From evolutionary game theory to biological markets, this approach is now flourishing.



Notes and References

[1] (Charles Darwin, 1859)
[2] (see Dennett, 1995; Gayon, 2003; Thagard, 1992, chapter 6)
[3] (C. Darwin, 1887, p. 84)
[4] (Burnet, [ca. 1692]1965, II, x),
[5] (Hestmark, 2000; Linnaeus, 1751).
[6] (Smith, [1759] 2002, p. 90)
[7] (Lyell, [1830-33]1853, p. 664)
[8] (Bowler, 1976; Ghiselin, 1978, 1995, 1999; Hammerstein & Hagen, 2005; Hodgson, 2001; Schabas, 2005)
[9] in “Morphology of Organisms” (1866); see (Stauffer, 1960).
[10] (Ghiselin, 1999, p. 7).

• Bowler, P. J. (1976). Malthus, Darwin, and the Concept of Struggle. Journal of the History of Ideas, 37(4), 631-650.
• Burnet, T. ([ca. 1692]1965). The sacred theory of the earth. Carbondale,: Southern Illinois University Press.
• Darwin, C. (1859). On the origin of species by means of natural selection. London,: J. Murray.
• Darwin, C. (1887). Autobiography. In F. Darwin (Ed.), The life and letters of Charles Darwin, including an autobiographical chapter (Vol. 1, pp. 26-106). London: John Murray.
• Dennett, D. C. (1995). Darwin's dangerous idea : evolution and the meanings of life. New York: Simon & Schuster.
• Gayon, J. (2003). From Darwin to Today in Evolutionary Biology. In J. Hodge & G. Radick (Eds.), The Cambridge Companion to Darwin (pp. 240-264). Cambridge: Cambridge University Press.
• Ghiselin, M. T. (1978). The Economy of the body The America Economic Review, 68 (2), 233-237.
• Ghiselin, M. T. (1995). Perspective: Darwin, progress and economic principle. Evolution, 49(6), 1029-1037.
• Ghiselin, M. T. (1999). Darwinian monism: the economy of nature. In P. Koslowski (Ed.), Sociobiology and bioeconomics : the theory of evolution in biological and economic theory (pp. x, 341 p.). Berlin ; New York: Springer.
• Hammerstein, P., & Hagen, E. H. (2005). The second wave of evolutionary economics in biology. Trends in Ecology & Evolution, 20(11), 604.
• Hestmark, G. (2000). Oeconomia Naturae L. Nature, 405(6782), 19.
• Hodgson, G. M. (2001). Bioeconomics. In P. A. O'Hara (Ed.), Encyclopedia of Political Economy (pp. 37-41). London ; New York: Routledge/Taylor & Francis Group.
• Linnaeus, C. (1751). Specimen Academicum de Oeconomia Naturae. Amoenitas Academicae, 2, 1-58.
• Lyell, C. ([1830-33]1853). Principles of geology; or, The modern changes of the earth and its inhabitants considered as illustrative of geology (9th and entirely rev. ed.). London,: J. Murray.
• Schabas, M. (2005). The natural origins of economics. Chicago: University of Chicago Press.
• Smith, A. ([1759] 2002). The theory of moral sentiments. Cambridge, U.K. ; New York: Cambridge University Press.
• Stauffer, R. C. (1960). Ecology in the Long Manuscript Version of Darwin's" Origin of Species" and Linnaeus'" Oeconomy of Nature". Proceedings of the American Philosophical Society, 104(2), 235-241.
• Thagard, P. (1992). Conceptual revolutions. Princeton, N.J.: Princeton University Press.

A glimpse at the evolution of the fearing and trusting brain

Together with other mechanisms, the amygdala is involveld in a complex neural circuitry that transforms photons hitting your eyes into the feeling that "Mom is mad at me because I break her favorite vase". Often referred to as the fear center, the amygdala is more like an online supervisory system that sets levels of alert. Many of its activities are of a social nature. Explicit and implicit distrust of faces elicits amygdala activation (Winston et al., 2002), while trust is increased with amygdala impairment (Adolphs et al., 1998). Moreover, the trust enhancing effect of oxytocin is mediated by amygdalar modulation: oxytocin reduces fear and hence allows trusting. In a nutshell, emotional memorization, learning and modulation performed by the amygdala obeys the following flowchart:

(from Schumann 1998)

A subpart of the amygdala, the lateral nucleus, processes information about social stimuli (such as facial expression). Autistic individuals tend to have impaired lateral nucleus, which makes sense if this nucleus is an important social-cognitive device (autistic subjects perform poorly in task that involves mental states attribution or other social inferences).According to Emery and Amaral (2000), inputs form the visual neocortex cortex enters the amygdala through the lateral nucleus, where its "emotional meaning" is attributed (I know, it is simplification...); the basal nucleus adds information about the social context. Hence this nucleus acts as a sensory integrator (LeDoux, 2000).

In a new paper in American Journal of Physical Anthropology, Barger et al. studied the relative size of different nuclei of the amygdala in different primates (humans, chimpanzee, bonobo, gorilla, etc.). The study revealed that the human lateral nucleus represents a larger fraction of the amygdala:

The authors conclude:

The large size of the human L [lateral nuclei] may reflect the proliferation of the temporal lobe over the course of hominid evolution, while the inverse may be true of the gorilla. The smaller size of the orangutan AC [amygdaloid complex] and BLD [Baso-lateral division] may be related to the diminished importance of interconnected limbic structures in this species. Further, there is some evidence that the orangutan, which exhibits one of the smallest group sizes on the contin- uum of primate sociality, may also be distinguished neuroanatomically from the other great apes, suggesting that social pressures may play a role in the development of the AC in association with other limbic regions.

Living in large groups thus may have shaped the evolution of emotional processing capacities of our brains. In the economy of nature, negotiating our way in a complex social world requires accute and specialized cognitive capacities in order to cooperate, trust, reciprocate, etc. This research show the potentials of evolutionary cognitive neuroscience (see this post).


References

• Adolphs R, Tranel D, Damasio AR (1998) The human amygdala in social judgment. Nature 393: 470-474.
• Barger, N. Stefanacci, L., & Semendeferi, K. (2007) A comparative volumetric analysis of the amygdaloid complex and basolateral division in the human and ape brain. American Journal of Physical Anthropology.
• Emery and Amaral, 2000 N.J. Emery and D.G. Amaral, The role of amygdala in primate social cognition. In: R.D. Lane and L. Nadel, Editors, Cognitive Neuroscience of Emotion, Oxford Univ. Press, New York (2000), pp. 156–191.
• LeDoux JE (2000) Emotion circuits in the brain. Annu Rev Neurosci 23: 155-184
• Schumann, J.A. 1998. Language Learning. Vol. 48 Issue s1 Page ix-326
• Winslow JT, Insel TR (2004) Neuroendocrine basis of social recognition. Curr Opin Neurobiol 14: 248-253
• 
  

Altruism: a research program

Phoebe: I just found a selfless good deed; I went to the park and let a bee sting me.
Joey: How is that a good deed?
Phoebe: Because now the bee gets to look tough in front of his bee friends. The bee is happy and I am not.
Joey: Now you know the bee probably died when he stung you?
Phoebe: Dammit!
- [From Friends, episode 101]

Altruism is a lively research topic. The evolutionary foundations, neural substrates, psychological mechanisms, behavioral manifestations, formal modeling and philosophical analyses of cooperation constitute a coherent—although not unified—field of inquiry. See for instance how neuroscience, game theory, economic, philosophy, psychology and evolutionary theory interact in Penner et al. 2005; Hauser 2006; Fehr and Fischbacher 2002; Fehr and Fischbacher 2003. The nature of prosocial behavior, from kin selection to animal cooperation to human morality can be considered as a progressive Lakatosian research programs. Altruism has a great conceptual "sex-appeal" because it is mystery for two types of theoreticians: biologists and economists. They both wonder why an animal or an economic agent would help another: since these agents maximize fitness/utility, altruistic behavior is suboptimal. Altruims (help, trust, fairness, etc.) seems intuitively incoherent with economic rationality and biological adaptation, with markets and natural selection. Or is it?

In the 60's, biologists challenged the idea that natural selection is incompatible with altruism. Hamilton (1964a, 1964b) and Trivers (1971) showed that biological altruism makes sense. An animal X might behave altruistically toward another Y because they are genetically related: in doing so, X maximize the copying of its gene, since many of its genes will be hosted in Y. Thus the more X and Y are genetically related, the more X will be ready to help Y. This is kin altruism. Altruism can also be reciprocal: scratch my back and I'll scratch yours. Tit-for-tat, or reciprocal altruism also makes sense because by being altruistic, one may augments its payoff. X helps Y, but the next time Y will help X; thus it is better to help than not to help. In both cases, the idea is that altruism is a mean not an end. Others argue that more complex types of altruisms exists. For instance, X can help Y because Y already helped Z (indirect reciprocity). In this case, the tit-for-tat logic is extended to agents that the helper did not meet in the past. Generalized reciprocity (see this previous post) is another type of altruism: helping someone because someone helped you in the past. This altruism does not require memory or personal identification. X helps someone because someone else helped X. Finally, Strong reciprocity is the idea that humans display genuine altruism: strong reciprocators cooperate with cooperators, do not cooperate with cheaters, and are ready to punish cheaters even at a cost to themselves. Their proponents argue that it evolved through group selection.

Experimental economics and neuroeconomics also challenged the idea of rational, greedy, selfish actor (the Ayn Rand hero). Experimental game theory showed that, contrarily to orthodox game theory, subjects cooperate massively in prisoner’s dilemma (Ledyard, 1995; Sally, 1995). Rilling et al. showed that players enjoy cooperating. Players who initiate and players who experience mutual cooperation display activation in nucleus accumbens and other reward-related areas such as the caudate nucleus, ventromedial frontal/orbitofrontal cortex, and rostral anterior cingulate cortex (Rilling et al., 2002). In another experiment, the presentation of faces of intentional cooperators caused increased activity in reward-related areas (Singer et al. 2004). In the ultimatum game, proposers make ‘fair’ offers, about 50% of the amount, responders tend to accept these offers and reject most of the ‘unfair’ offers (less than 20%;Oosterbeek et al., 2004). Brain scans of people playing the ultimatum game indicate that unfair offers trigger, in the responders’ brain, a ‘moral disgust’: the anterior insula (associated with negative emotional states like disgust or anger) is more active when unfair offers are proposed (Sanfey, Rilling, Aronson, Nystrom, & Cohen, 2003). Subjects experiment this affective reaction to unfairness only when the proposer is a human being: the activation is significantly lower when the proposer is a computer. Moreover, the anterior insula activation is proportional to the degree of unfairness and correlated with the decision to reject unfair offers (Sanfey et al., 2003: 1756). Fehr and Fischbacher (2002) suggested that economic agents are inequity-averse and have prosocial preferences. Thus they modified the utility functions to account for behavioral (and now neural) data. In Moral Markets: The Critical Role of Values in the Economy, Paul Zak proposes a radically different conception of morality in economics:

The research reported in this book revealed that most economic exchange, whether with a stranger or a known individual, relies on character values such as honesty, trust, reliability, and fairness. Such values, we argue, arise in the normal course of human interactions, without overt enforcement—lawyers, judges or the
police are present in a paucity of economic transactions (...). Markets are moral in two senses. Moral behavior is necessary for exchange in moderately regulated markets, for example, to reduce cheating without exorbitant transactions costs. In addition, market exchange itself can lead to an understanding of fair-play that can build social capital in nonmarket settings. (Zak, forthcoming)

See how this claim is similar to :

The two fundamental principles of evolution are mutation and natural selection. But evolution is constructive because of cooperation. New levels of organization evolve when the competing units on the lower level begin to cooperate. Cooperation allows specialization and thereby promotes biological diversity. Cooperation is the secret behind the open-endedness of the evolutionary process. Perhaps the most remarkable aspect of evolution is its ability to generate cooperation in a competitive world. Thus, we might add "natural cooperation" as a third fundamental principle of evolution beside mutation and natural selection. (Nowak, 2006)

Hence, biological and economic theorizing followed a similar path: they started first with the assumption that agents value only their own payoff; evidence suggested then that agents behave altruistically and, finally, theoretical models were amended and now incorporate different kinds of reciprocity.

So is it good news? Are we genuinely altruistic? First a precision: there is a difference between biological and psychological altruism, and the former does not entail the latter; biological altruism is about fitness consequencences (survival and reproduction), while psychological altruism is about motivation and intentions:

Where human behaviour is concerned, the distinction between biological altruism, defined in terms of fitness consequences, and ‘real’ altruism, defined in terms of the agent's conscious intentions to help others, does make sense. (Sometimes the label ‘psychological altruism’ is used instead of ‘real’ altruism.) What is the relationship between these two concepts? They appear to be independent in both directions (...). An action performed with the conscious intention of helping another human being may not affect their biological fitness at all, so would not count as altruistic in the biological sense. Conversely, an action undertaken for purely self-interested reasons, i.e. without the conscious intention of helping another, may boost their biological fitness tremendously (Biological Altruism, Stanford Encyclopedia of Philosophy; see also a forthcoming paper by Stephen Stich and the classic Sober & Wilson 1998).

The interesting question, for many researchers, is then: what is the link between biological and psychological altruism? A common view suggests non-human animals are biological altruists, while humans are also psychological atruists. I would like argue against this sharp divide and briefly suggest three things:

1. Non-humans also display psychological altruism
2. Human altruism is strongly influenced by biological motives
3. Prosocial behavior in human and non-human animals should be understood as a single phenomena: cooperation in the economy of nature

1. Non-humans also display psychological altruism


A discussed in a previous post, a recent research paper showed that rats exhibit generalized reciprocity: rats who had previously been helped were more likely (20%) to help unknown partner than rats who had not been helped. Although the authors of the paper take a more prudent stance, I consider generalized reciprocity as psychological altruism (remember, it can be both): rats cooperate because they "feel good", and that feeling is induced by cooperation, not by a particular agent. Hence their brain value cooperation (probably thanks to hormonal mechanisms similar to ours) in itself, even if there is no direct tit-for-tat. In the same edition of PLoS biology, primatologist Frans de Waal (2007) also argue that animals show signs of psychological altruism; it it particularly clear in an experiment (Warneken et al, again, in the same journal) that show that chimpanzees are ready to help unknown humans and conspecifics (hence ruling out kin and tit-for-tat altruism), even at a cost to themselves. Here is the description of the experiments:

In the first experiment, the chimpanzee saw a person unsuccessfully reach through the bars for a stick on the other side, too far away for the person, but within reach of the ape. The chimpanzees spontaneously helped the reaching person regardless of whether this yielded a reward, or not. A similar experiment with 18-month-old children gave exactly the same outcome. Obviously, both apes and young children are willing to help, especially when they see someone struggling to reach a goal. The second experiment increased the cost of helping. The chimpanzees were still willing to help, however, even though now they had to climb up a couple of meters, and the children still helped even after obstacles had been put in their way. Rewards had been eliminated altogether this time, but this hardly seemed to matter. One could, of course, argue that chimpanzees living in a sanctuary help humans because they depend on them for food and shelter. How familiar they are with the person in question may be secondary if they simply have learned to be nice to the bipedal species that takes care of them. The third and final experiment therefore tested the apes' willingness to help each other, which, from an evolutionary perspective, is also the only situation that matters. The set-up was slightly more complex. One chimpanzee, the Observer, would watch another, its Partner, try to enter a closed room with food. The only way for the Partner to enter this room would be if a chain blocking the door were removed. This chain was beyond the Partner's control—only the Observer could untie it. Admittedly, the outcome of this particular experiment surprised even me—and I am probably the biggest believer in primate empathy and altruism. I would not have been sure what to predict given that all of the food would go to the Partner, thus creating potential envy in the Observer. Yet, the results were unequivocal: Observers removed the peg holding the chain, thus yielding their Partner access to the room with food (de Waal)

(image from Warneken et al video)

2. Human altruism is strongly influenced by biological motives

In many cases, human altruism appear as a complex version of biological altruism (see Burnham & Johnson, 2005. The Biological and Evolutionary Logic of Human Cooperation for a review). For instance, Madsen et al. (2007) showed that humans behave more altruistically toward their own kin when there is a significant genuine cost (such as muscular pain), an attitude also mirrored in study with questionnaires (Stewart-Williams 2007): when the cost of helping augments, subjects are more ready to help siblings than friends. Other studies showed that facial similarity enhances trust (DeBruine 2002). In each cases, there is a mechanism whose function is to negotiate personal investments in relationships in order to promote the copying of genes housed either in people of—or people who seems to be of—our kin.

Many of these so called altruistic behavior can be explained only by the operations of hyper-active agency detectors and a bias toward fearing other people’s judgement. When they are not being or feeling watched, peoples behave less altruistically. Many studies show that in the dictator game, a version of the ultimatum game where the responder has to accept the offer, subjects always make lower offers than in the ultimatum (Bolton, Katok, and Zwick 1998). Offers are even lower in the dictator game when donation is fully anonymous (Hoffman et al. 1994). When subjects feel watched, or think of agents, even supernatural ones, they tend to be much more altruistic. When a pair of eyes is displayed in a computer screen, almost twice as many participants transfer money in the dictator game (Haley and Fessler 2005), and people contribute 3 times more in an honesty box for coffee' when there is a pair of eyes than when there is pictures of a flower (Bateson, Nettle, and Roberts 2006). The sole fact of speaking of ghosts enchances honest behavior in a competitive taks (Bering, McLeod, and Shackelford 2005), while priming subjects with the God concept in the anonymous dictator game (Shariff and Norenzayan in press).

These reflections also applies to altruistic punishment. First, it is enhanced by an audience. (Kurzban, DeScioli, and O'Brien 2007) showed that with a dozen participants, punishment expenditure tripled. Again, appareant altruism is instrumental in personal satisfaction. Other research suggest that altruism is also an advantage in sexual selection: "people preferentially direct cooperative behavior towards more attractive members of the opposite sex. Furthermore, cooperative behavior increases the perceived attractiveness of the cooperator" (Farrelly et al., 2007).

An interesting framework to understand altruims is Hardy (no relation with me) & Van Vugt (2006) theory of competitive altruism: "individuals attempt to outcompete each other in terms of generosity. It emerges because altruism enhances the status and reputation of the giver. Status, in turn, yields benefits that would be otherwise unattainable." We need, however, a more general perspective.


3. Prosocial behavior in human and non-human animals should be understood as a single phenomena: cooperation in the economy of nature

All organic beings are striving to seize on each place in the economy of nature - (Darwin, [1859] 2003, p. 90)

With Darwin, natural economy began to be understood with the conceptual tools of political economy. The division of labor, competition (“struggle” in Darwin’s words), trading, cost, the accumulation of innovations, the emergence of complex order from unintentional individual actions, the scarcity of resources and the geometric growth of populations are ideas borrowed from Adam Smith, Thomas Malthus, David Hume and other founders of modern economics. Thus, the economy of nature ceased to be an abstract representation of the universe and became a depiction of the complex web of interactions between biological individuals, species and their environment—the subject matter of ecology. Consequently, Darwin’s main contributions are his transforming biology into a historical science—like geology—and into an economic science.

I take the economy-of-nature principle to be a refinement of the natural selection principle: while it describes general features of the biosphere, it puts emphasis on the intersection between individual biographies and natural selection, and especially on decision-making. On the one hand, the decisions biological individuals make increase or decrease their fitness, and thus good decision-makers are more likely to propagate their genes. On the other hand, natural selection is likely to favor good decision-makers and to get rid of bad decision-makers. Thus, if our best descriptive theories of animal and human economic behavior indicate that all these agents have prosocial preferences and make altruistic decisions, then these preferences and decisions are not maladaptive and irrational. They must have an evolutionary and an economic payoff. Markets and natural selections requires cooperation, even if the deep motivations are partly selfish. Fairness, equity and honesty are social goods in the economy of nature, human and non-human.

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