What is the primary characteristic of altruism?

Altruism is primarily characterized by self-sacrifice, which refers to actions that are intended to benefit others at a cost to oneself. In the context of biology and evolutionary theory, altruism is often observed in social species where an individual may act in a way that enhances the survival or reproductive success of others, even if it places their own survival or reproduction at risk. This could mean sharing resources, protecting others from predators, or assisting in raising offspring that are not their own.

The focus on self-sacrifice underscores the essence of altruism; it goes beyond mere cooperation, which may still carry elements of self-benefit, as individuals may cooperate to enhance their own chances of survival or success in a shared environment. Altruism, as a characteristic, emphasizes the altruistic individual's willingness to endure costs or risks for the benefit of others, which is distinct from the notions of competition and self-benefit, where actions are typically directed at personal gain rather than the welfare of others.