Reciprocal Altruism

Sharing food is a good example. Suppose an animal captures a food source which is so plentiful that it cannot consume it all alone before it goes off. Sharing it with others may entail getting slightly less food now, for the possibility of more food later (when it might be sorely needed) if the recipients reciprocate the altruistic action.

Reciprocal altruists are taking something of a risk - since the rewards come later, they are relying on the good will (and good memory) of the recipient to return the favour when they get the chance. Pattens of reciprocal altruism can last a lifetime, but there is always the possibility that the recipient may choose to defect - i.e. accept the altruistically offered help, but then refuse to reciprocate. Axelrod & Hamilton (1981) noticed that this problem is identical to one in economics, called The Prisoner’s Dilemma.

For reciprocal altruism to exist, the same individuals must come into regular contact, and there need to be repeated opportunities for actions that cost the altruist less than they benefit the recipients. Participants must also identify one another and accurately recall previous trades to avoid being exploited by defectors. Szabo presents a clear explanation of how money may have arisen from the need of early humans to keep track of acts of reciprocal altruism.

There are many practical examples of reciprocal altruism. Food sharing is probably the most common - Wilkinson noticed that after a night hunting, vampire bats are sometimes hungry and sometimes bloated with blood. The successful ones often regurgitate blood to unsuccessful ones, but tended to give it to ones who had been altruistic to them in the past. Other examples include cleaner fish that trust others not to devour them while they clean food from inside their mouths and animals that reveal their position to potential predators by issuing warning calls.

Since reciprocal altruists must make a point of choosing other altruists to help, this increases the probability of there being genetic similarity between them to underly the similarity of behaviour pattern. Reciprocal altruism may therefore also be, as Rothstein argues, impossible to separate clearly from kin selection. This would help explain how patterns of reciprocal altruism could first become established.

Downloads	Category	Title	Author(s)	Date	Reference
	Evolution	Heterogeneity Stabilizes Reciprocal Altruism Interactions	Micheal Fishman, Arnom Lotem & Lewi Stone	2000-12-09	Academic Press Journal of Theoretical Biology 209, pp.87-95
	Evolution	Evolution of Indirect Reciprocity by Image Scoring - The Dynamics of Indirect Reciprocity	Martin A. Nowak & Karl Sigmund	1998 May	International Institute for Applied Systems Analysis
	Evolution	From Reciprocity to Unconditional Altruism Through Signalling Benefits	Lotem, Fishman & Stone	2002-12-10	Proceedings of The Royal Society London 270, pp.199-205
	Game Theory	Social Reciprocity	Jeffrey Carpenter & Peter Matthews	2002 Jul	Middlebury College Vermont Middlebury College Economics Discussion Paper 02-29
	Psychology	Recipients of altruism likely to pass it on	Heather Smith	2002 Sep
	Psychology	Altruism, Equity & Reciprocity in A Gift Exchange Experiment	Gary Charness & Ernan Haruvy	1999 Mar
	Psychology	Information Seeking and Reciprocity : A Transformational Analysis	Marcello Gallucci & Marco Perugini	2002-02-19	European Journal of Social Psychology
	Economics	Altruism, Exchange or Indirect Reciprocity - What do the Data on Family Transfers Show	Luc Arrondel & André Masson
	Economics	Verified Trust - Reciprocity, Altruism & Noise in Trust Games	Marius Brulhart & John-Claude Usunier
	Evolution	Reciprocal altruism and group formation	Evelien Zeggelin, Henk de Vos & Donald Elsas	2000-06-30	Journal of Artificial Societies and Social Simulation 3 (Issue 3)
	Computer Science	Self-Interest, Reciprocity, and Participation in Online Reputation Systems	Dellarocas, Fan & Wood
	Game Theory	Positive reciprocity and intentions in trust games	Kevin McCabe, Mary Rigdon & Vernon Smith	2002-04-05	Elsevier Journal of Economic Behavior & Organization 52 (Issue 2003), pp.267-275
	Evolution	Strong Reciprocity, Human Cooperation and the Enforcement of Social Norms	Ernst Fehr, Urs Fischbacher & Simon Gächter	2002	Human Nature , pp.1-25
	Evolution	Strong Reciprocity May Evolve With or Without Group Selection	Samuel Bowles, Ernst Fehr & Herbert Gintis	2003-12-10
	Evolution	Strong Reciprocity and Human Sociality	Herbert Gintis	2000-05-10
	Economics	The Economic Impacts of Altruism, Trust and Reciprocity - An Experimental Approach to Social Capital	Marco Castillo & Michael Carter	2002 Jan
	Psychology	Economists find money is more precious than time	Kim Klaver	2002-08-22
	Economics	Come identificare fiducia e reciprocità		2006-06-14