Altruism and cooperation have long puzzled biologists. Robert Kurzban offers a fine overview of the subject, which also includes the humans.[1] Altruism is defined as behavior that benefits another organism, not closely related, while being apparently detrimental to the organism performing the behavior. Both benefit and detriment are defined in terms of their contribution to inclusive fitness. An organism behaving altruistically thus necessarily endures a fitness cost.[2]

Broadly speaking, for reciprocal altruism to work, the following minimum requirements must be met. First, the environment must be one in which there are benefits to be conferred. Second, organisms must have repeated interactions with one another. Third, organisms must have sufficient information-processing abilities that they are able to distinguish among individuals and remember which ones have and have not delivered benefits in the past. And forth, organisms must have sufficient information-processing sophistication and behavioral flexibility that they can interact with other organisms contingent on the history of interaction.[3]

Two of these requirements for the evolution of cooperation through reciprocal altruism refer to the structure of the environment. Is there evidence that these requirements have been met during human evolution? Although it is impossible to answer this question with certainty, Kurzban argues that there is sufficient evidence that our ancestral conditions did have these particular features. If lucky hunters shared their food with their less fortunate band members, each would have been able to buffer food variability that a hunting lifestyle entails.[4] In addition, humans have specialized cognitive mechanisms for detecting cheaters.[5]

However, Kurzban points out that it is unreasonable to expect that the specialized cognitive machinery designed to generate adaptive behavior in ancestral environments will continue to do so in modern ones. Systems designed to function well in tight-knit and stable communities might be entirely inappropriate in the modern world, in which encounters with others are frequently one-shot.[6] Interestingly, Kurzban leaves it at this. By implication, the blissful ancestral conditions engendering reciprocal altruism are unreachable today. One is left daydreaming about tight-knit and stable communities of yesteryear.

Footnotes

1. Kurzban, R., “Biological Foundations of Reciprocity,” in Ostrom, E. and J. Walker, eds., Trust and Reciprocity: Interdisciplinary Lessons from Experimental Research, New York: Russell Sage Foundation, 2003, pp. 105-127.

2. Op. cit., p. 105.

3. Op. cit., p. 111.

4. Op. cit., p. 115.

5. Op. cit., p. 117.

6. Op. cit., p. 119.