motivation, in psychology, the intention of achieving a goal, leading to goal-directed behavior. Some human activity seems to be best explained by postulating an inner directing drive. While a drive is often considered to be an innate biological mechanism that determines the organism's activity (see instinct), a motive is defined as an innate mechanism modified by learning. In this view human drives serve to satisfy biological needs, such as hunger, while motives serve to satisfy needs that are not directly tied to the body requirements, such as companionship. Learned motives are sometimes linked with drives; e.g., the motivation to achieve social status is often viewed as a derivitive of the sex drive. Motives are sometimes classed as deficiency motives, such as the need to remove the physiological deficiency of hunger or thirst, or abundancy motives, i.e., motives to attain greater satisfaction and stimulation. American psychologist Abraham Maslow has classified motives into five developmental levels, with the satisfaction of physiological needs most important and esteem and self-actualization needs least important. According to Maslow, the most basic needs must be satisfied before successively higher needs can emerge. Cognitive psychologists such as Albert Bandura have suggested that individual mental processes, such as beliefs, play an important role in motivation, through the expectation of certain reinforcements for certain behaviors. Studies have shown that humans and other animals are likely to seek sensory stimulation, even where there may be no foreseeable goal. In recent years, the use of various tools for brain scanning has worked toward the discovery of a neurological basis for motivation.