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.
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• 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.

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).

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