Behavior is primarily explained in terms of mental processes which are unobservable, and secondarily in terms of observable environmental factors. This approach seems to be generic to accounting research which utilizes an "expectancy theory" framework. Expectancy theory holds that behavior results from a decision-making process in which it is assumed that Individuals place different values (ordinal or cardinal) on different outcomes. Behavior results from decisions made by the individual after considering the relationship between the various decisions and the values of those decisions. In contrast, conditioning theory does not postulate metaphysical assumptions concerning the nature of the individual. Conditioning theory holds that all behavior may be pragmatically explained in terms of the history of interactions between an organism and its environment. Conditioning theory maintains that purposive connotations, such as needs or drives, add nothing to the scientific analysis of behavior.