Behavior is directed toward or away from particular stimuli, as well as activities that involve interacting with those stimuli. Organisms seek access to some stimulus conditions (i.e., food, water, sex) and avoid others (i.e., pain, discomfort), in both active and passive click here ways. Moreover, motivated behavior typically takes place in phases (Table 1). The terminal stage

of motivated behavior, which reflects the direct interaction with the goal stimulus, is commonly referred to as the consummatory phase. The word “consummatory” (Craig, 1918) does not refer to “consumption,” but instead to “consummation,” which means “to complete” or “to finish.” In view of the fact that motivational stimuli usually are available at some physical or psychological distance from the organism, the only way to gain access to these stimuli is to engage in behavior that brings them closer, or makes their occurrence selleck chemicals more likely. This phase of motivated behavior often is referred to as “appetitive,” “preparatory,” “instrumental,” “approach,” or “seeking.” Thus, researchers sometimes distinguish between “taking” versus “seeking” of a natural stimulus such as food (e.g.,

Foltin, 2001), or of a drug reinforcer; indeed, the term “drug-seeking behavior” has become a common phrase in the language of psychopharmacology. As discussed below, this set of distinctions (e.g., instrumental versus consummatory or seeking versus

taking) is important for understanding mafosfamide the effects of dopaminergic manipulations on motivation for natural stimuli such as food. In addition to “directional” aspects of motivation (i.e., that behavior is directed toward or away from stimuli), motivated behavior also is said to have “activational” aspects (Cofer and Appley, 1964; Salamone, 1988, 2010; Parkinson et al., 2002; Table 1). Because organisms are usually separated from motivational stimuli by a long distance, or by various obstacles or response costs, engaging in instrumental behavior often involves work (e.g., foraging, maze running, lever pressing). Animals must allocate considerable resources toward stimulus-seeking behavior, which therefore can be characterized by substantial effort, i.e., speed, persistence, and high levels of work output. Although the exertion of this effort can at times be relatively brief (e.g., a predator pouncing upon its prey), under many circumstances it must be sustained over long periods of time. Effort-related capabilities are highly adaptive, because in the natural environment survival can depend upon the extent to which an organism overcomes time- or work-related response costs. For these reasons, behavioral activation has been considered a fundamental aspect of motivation for several decades.