Not one man in a billion, when taking his dinner, ever thinks of utility. He eats because the food tastes good and makes him want more. If you ask him why he should want to eat more of what tastes like that, instead of revering you as a philosopher he will probably laugh at you for a fool. —William James (1890/1950, p. 386)
Many species of waterfowl display a fascinating behavioral sequence. Upon observation of an egg that has rolled away from its nest, the brooding animal waddles over to the egg and nudges it back to the nest with its beak (Lorenz, 1965). Repeated displacement of an egg results in repeated replacement by the animal. For human observers, it’s difficult not to attribute humanlike motives—it appears as though the bird really wants to keep all of its eggs inside the nest. In fact, if we had observed a person engaging in the same egg-nudging behavior, the most sensible explanation would be that this person wants—is motivated—to keep the eggs inside the nest. But appearances are deceiving. Simple experiments have revealed that these birds will also perform the same egg-nudging behavior on objects such as baseballs and doorknobs that have been placed in the vicinity of the nest (Tinbergen, 1951). Termed fixed action patterns, these seemingly complex behaviors are in fact simple stimulus–response reflexes. Waterfowl do not possess goal-directed motives that we are tempted to attribute—they don’t really care about the welfare of their eggs, per se. Whatever “motive” underlies the egg-nudging fixed action pattern, it is manifestly distinct from the apparent function served by it (for a similar discussion, see Schaller, 2003).1 The discovery of fixed action patterns had profound implications for biologists’ understanding of animal behavior. It provoked researchers to address several critical issues, and it led to a fruitful meta-theoretical framework for studying behavioral tendencies (Lorenz, 1965; Tinbergen, 1951). The essential aspects of the framework are as follows. First, fixed action patterns reveal a history of evolutionary selection. Any behavior that is part of a species’ natural repertoire suggests natural selection of behavioral variants that conferred fitness benefits to predecessors (Bolles, 1970). (“Confer fitness benefits” is shorthand for saying that the trait in question increased the likelihood of survival and reproduction for the ancestral animals that possessed the trait.) Second, if fixed action patterns conferred fitness benefits, this implies that they served some adaptive function for the ancestral animals. One might reasonably hypothesize that the egg-nudging behavior was selected because it served—usually reliably—the fitness-enhancing function of gathering eggs that rolled away from the nest (this sort of explanation of behavior is also known as “ultimate” explanation). Finally, careful empirical investigation of f ixed action patterns uncovers the specific mechanisms that underlie them. In the case of the egg-nudging sequence, waterfowl seem to possess a mechanism that detects superficially egglike objects and triggers the nudging behavior (this sort of explanation of behavior is also known as “proximate” explanation). Under some circumstances, such mechanisms produce functionally futile responses (in terms of fitness), which, ironically, expose the design features of the mechanisms (by observing birds collecting baseballs and doorknobs, researchers were able to infer that the birds respond mechanically to objects that look roughly like eggs instead of accurately identifying their own eggs under variable circumstances). In this chapter, we describe lines of research in which a similar framework has been applied to the study of human motives. We begin by describing the theoretical foundations of the evolutionary approach and the ways in which this approach can generate new and testable hypotheses regarding various psychological processes. We then review research lines in various domains of interpersonal phenomena that have tested those hypotheses. Throughout this endeavor we have tried to apply the lessons learned from the humble fixed action patterns. This is not to suggest that humans exhibit behaviors that could properly be called fixed action patterns. Nonetheless, the key idea—that seemingly goal-directed motives may in fact be largely automatic programs—can be usefully applied to the study of human behavior. Perhaps the most important lesson for psychological researchers is to refrain from attaching humanlike goal-directed motives to observed behavior, even, paradoxically, to human behavior.2 This is because the actual motives that drive behavior may be logically independent of the apparent goal served by them, even if we are tempted—as in the case of fixed action patterns—to attribute rational, goaldirected motives. Bowlby (1969) similarly noted the need to separate “function” from “causation” when explaining instinctive behavior. For example, to say that “a bird engages in egg-nudging behavior in order to keep them in the nest” conflates function (the evolutionary reason for the existence of the behavior) with actual causes of the behavioral pattern (the mechanical program and the contextual triggers). As we illustrate below, the automatic nature of goal-like “motives” can be exposed given appropriate circumstances (Schaller, 2003), and, like waterfowl, people may occasionally exhibit responses that appear functionally futile to “wiser” observers (such as experimental psychologists). Indeed, instances of functionally futile behavior may be an inevitable consequence of psychological programs shaped by evolution. Of course, the notion that various primes can automatically trigger behavior is not new (e.g., Bargh, Chen, & Burrows, 1996). Thus, many psychologists will have no difficulty accepting the argument that many behavioral reactions are reflexive and relatively unmediated. Our present thesis pertains more to motivation researchers: Goal-directed motives are constructs to be demonstrated, not assumed (cf. Pittman, 1998).
