TWO CONCEPTS

The concept of altruism has led a double life. In ordinary discourse, as well as in psychology and the social sciences, altruism refers to behaviors that are produced because people have certain sorts of motives. In evolutionary biology, on the other hand, the concept is applied to behaviors that enhance the fitness of others at expense to self.

A behavior can be altruistic in the evolutionary sense without being an example of psychological altruism. A plant that leeches insecticide into the soil may be an altruist, if the insecticide benefits its neighbors and imposes an energetic cost on the producer. In saying this, I am not attributing a mind to the plant. Evolutionary altruism has to do with the fitness consequences of the behavior, not with the mechanisms inside the plant (mental or otherwise) that cause the plant to behave as it does.

Symmetrically, a behavior can be altruistic in the psychological sense without being an example of evolutionary altruism. If I give you a volume of Beethoven piano sonatas (or a package of contraceptives) out of the goodness of my heart, my behavior may be psychologically altruistic. However, the gift giving will not be an example of evolutionary altruism, if the present fails to augment your prospects for survival and reproductive success.