altruism
n. an apparently unselfish behavior that provides benefit to others at some cost to the individual. In humans, it covers a wide range of behaviors, including volunteerism and martyrdom, but the degree to which such behaviors are legitimately without egoistic motivation is subject to debate. In animal behavior, it is difficult to understand how altruism could evolve in a species since natural selection operates on individuals. However, organisms displaying altruism can benefit if they help their relatives (see kin selection) or if an altruistic act is subsequently reciprocated (reciprocal altruism). —altruistic
adj.
—altruist
n.