Final answer:
Social behavior where both the actor and recipient benefit is known as mutualism, characterized by reciprocal interactions that increase fitness for both parties.
Step-by-step explanation:
Social behavior in which both the "actor" and the "recipient" benefit is known as mutualism. This type of interaction is observed in various species, including humans, and can be contrasted with other forms of social behaviors, such as altruism, in which one individual benefits at their own expense. In mutualism, both parties gain from the interaction, leading to increased fitness and survival chances. An example of this is found in many monkey species where one monkey grooms another to remove parasites, and then the roles are reversed, signifying a reciprocal relationship. This behavior illustrates the principle of reciprocity where there is a give and take, benefiting both involved parties.