This chapter considers three basic, interrelated processes related to imaging differences, namely are the physiological, the cognitive, and the social. Underlying all the studies to be reported in this chapter is the assumption that the magnitude of a physiological response is a function of the vividness with which a relevant stimulus situation can be imaged. These studies have been divided into those concerned directly with affective processes, and those concerned with non-affective processes. There is strong evidence for both men and women that it is necessary to possess vivid, or at least moderately vivid, imagery if voluntary control over salivation output is to be achieved. These studies also demonstrate the methodological importance of varying the intensity or personal significance of stimulus (situation) variables, as well as varying the vividness of imaging ability (person) variables. The available evidence suggests that imagery is implicated in incidental learning, but probably not in intentional learning, at least for the types of task employed.