Altruism is acting for the good of others. It is a puzzling phenomenon, as an organism that helps another is likely to incur some reproductive cost. For example, less resources for its own offspring or an increased mortality risk (Reeve, 1998). This should mean that any genetic instructions that promote helping others should be eventually removed from the gene pool, as those individuals should have lower reproductive success. Essentially, there are two reasons why altruism is common:

(1) Kin Selection
By enhancing the reproductive success of close relatives, the individual is promoting the transfer of some of their own genes into the next generation. For example, a man has three children. Each child has 50% of his genetic material. If he sacrificed his own further reproductive success for the benefit of the children, there would still be 150% of his genes in the next generation which are still able to be passed down to subsequent generations.

(2) Reciprocal Altruism
Humans have fantastic memories, and many other species also have quite good memories also. Reciprocal altruism is the 'I'll scratch your back and you scratch mine' scenario. When animals live in communities where they encounter the same individuals often, and they are able to remember who did what and for whom, then reciprocal altruism is likely to be exercised as individuals remember who owes favours to them. This is a win-win situation.

This is only an overview of altruism. For an insight into one aspect of altrusim, the following paper can be viewed on the internet. Click of the title to go to it. THE EVOLUTION OF RECIPROCAL SHARING (1984) in Ethology and Sociobiology 5, pp. 5-14

Darwin's Theory of Evolution

Environment of Evolutionary Adaptation

Sexual Selection

The social function of intelligence

References and Bibliography

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