Altruism: Consideration and concern for others, as opposed to self-love or egoism, which can be a motivating influence.Game Theory: Theoretical construct used in applied mathematics to analyze certain situations in which there is an interplay between parties that may have similar, opposed, or mixed interests. In a typical game, decision-making "players," who each have their own goals, try to gain advantage over the other parties by anticipating each other's decisions; the game is finally resolved as a consequence of the players' decisions.Biological Evolution: The process of cumulative change over successive generations through which organisms acquire their distinguishing morphological and physiological characteristics.Cooperative Behavior: The interaction of two or more persons or organizations directed toward a common goal which is mutually beneficial. An act or instance of working or acting together for a common purpose or benefit, i.e., joint action. (From Random House Dictionary Unabridged, 2d ed)Helping Behavior: Behaviors associated with the giving of assistance or aid to individuals.Commodification: The social process by which something or someone comes to be regarded and treated as an article of trade or commerce.Group Structure: The informal or formal organization of a group of people based on a network of personal relationships which is influenced by the size and composition, etc., of the group.Ego: The conscious portion of the personality structure which serves to mediate between the demands of the primitive instinctual drives, (the id), of internalized parental and social prohibitions or the conscience, (the superego), and of reality.Ethics: The philosophy or code pertaining to what is ideal in human character and conduct. Also, the field of study dealing with the principles of morality.Competitive Behavior: The direct struggle between individuals for environmental necessities or for a common goal.Social Behavior: Any behavior caused by or affecting another individual, usually of the same species.Selection, Genetic: Differential and non-random reproduction of different genotypes, operating to alter the gene frequencies within a population.Games, Experimental: Games designed to provide information on hypotheses, policies, procedures, or strategies.Volunteers: Persons who donate their services.Spores, Protozoan: A vegetative stage in the life cycle of sporozoan protozoa. It is characteristic of members of the phyla APICOMPLEXA and MICROSPORIDIA.Motivation: Those factors which cause an organism to behave or act in either a goal-seeking or satisfying manner. They may be influenced by physiological drives or by external stimuli.