Final answer:
Altruistic behavior is costly to the actor but beneficial to the recipient, observed in many animal species as well as humans in extreme circumstances, such as during the 9/11 terrorist attacks. Evolutionary perspectives indicate that often these behaviors can indirectly contribute to the actor's genetic success.
Step-by-step explanation:
Behavior that is costly to the actor and beneficial to the recipient is known as altruistic behavior. Altruistic behaviors have been widely observed across the animal kingdom and include actions that might lower the individual’s fitness but increase another individual’s fitness. Examples include worker bees who support the queen despite having no ability to reproduce, meerkats standing guard to protect their colony, and wolves bringing meat to pack members not present during a hunt. While such behaviors are on the surface altruistic, evolutionary game theory suggests that many behaviors thought to be altruistic have underlying “selfish” components that ultimately contribute to an individual’s genetic success. Altruism in humans, such as the selfless acts during the 9/11 terrorist attacks, may involve extreme personal cost with intention of pure help to others without an expectation of direct benefit.