The effects of arousal on verbal learning and memory are presently controversial. Investigators using different definitions of arousal, different tasks, and different methods have (as one would expect) produced different findings in the literature: (a) Arousal during acquisition leads to poor immediate but better delayed recall; (b) Arousal during acquisition sometimes facilitates immediate as well as delayed recall; (c) Arousal may lead to decrease in semantic clustering: (d) Arousal may facilitate recall for material in which "order" cues are salient: and (e) Arousal may lead to a convergence in decision criteria while at the same time increasing sensitivity for certain kinds of material. Instead of five separate explanations, the paper proposes to account for these effects by a single explanatory model based on the effects of arousal on memory organization. A model, based on changes in the way material is organized for retrieval is developed which views arousal as facilitating memory when recall is based on the physical characteristics of stimuli and hindering recall when memory depends on the semantic aspects of the stimuli. The implications of this model for the research findings decribed in the literature are discussed. (Author)