Scientists have studied individual differences in imagery for well over a hundred years (e.g., Galton, 1880). During all this time, theorists have favored datadriven models in explaining imagery differences, such as those that assume the differences result from either the latency or the perceptual clarity with which images are formed. These data-driven models have had little to say about the role that prior knowledge or belief systems play in producing individual variability in image arousal or effectiveness. To emphasize the importance of concept-driven components, Katz (1983) proposed an interactive model in which he postulated that imaginal effectiveness results, in part, from the conjoint influence of three related knowledge states. These states can be characterized as "how-to knowledge;' "when-to knowledge;' and "self-knowledge." The goal of the interactive model is to understand when and how people use imagery mediators in their everyday activities. From this perspective, the research questions of interest revolve around the conditions under which imaginal processes are spontaneously employed. The present chapter is directed at separately examining the three knowledge states suggested by the model as they relate to memory-relevant situations. We should begin with a warning: imagery effects in memory have been widely discussed in the 15 years since the epochal book by Paivio (1971) and yet there is a relative paucity of research performed on the type of question to which we are directed by the interactional model. In this chapter the relevant literature is reviewed. The aim is not to provide conclusive evidence for the interactional model but to summarize and direct the reader to research questions and problems triggered by the model.
An Interactive Model of Imagery DifferencesThe basic assumption of the model is that most tasks do not have an obligatory mode of processing. That is, different operations applied to the same problem may prove effective in producing results, albeit not necessarily equally effective results (e.g., Simon, 1975; or the parallel race model suggested for imagery by Kosslyn, 1983