DESCRIPTION: Studies of the role of context in memory storage and retrieval provide a window through which investigators can gain an understanding of species-general and species-specific memory organization. Context refers to the background stimuli that are present when we learn something. Although these stimuli are not directly related to what we are learning, they can affect our ability to remember what we have learned. For example, changes in the context between learning and retention testing can disrupt retrieval. One organism in which a detailed study of contextual effects on retrieval has begun to provide unique information about memory organization is the human infant. This research has utilized a simple paradigm in which infants learn to move an overhead mobile by kicking one of their feet. Retention of the association between kicking and mobile movement is assessed by returning the infant to the experimental arrangement to see if the kicking response will occur at a rate that is not different from what was at the conclusion of learning and above what it was prior to learning. Research has found, for example, that 3-month-old infants who learn to move the mobile in the presence of either a highly distinctive bumper surrounding their crib, or while a selection of music is playing in the background, will not demonstrate retrieval at long intervals if the crib bumper or music present during the test of retention differs from what it had been during learning. Very different results have been obtained with ambient odor as the context. Here, changing the odor between learning and testing, or having no odor present during testing, disrupts retention even at short retention intervals. Furthermore, at longer retention intervals, forgetting occurs even when the original training odor is present during the retention test. The present research will delve further into the mystery of why olfactory context affects infant memory differently from visual or auditory context. This will aid our understanding of how infants process, store, and retrieve information. It will also add to the growing body of knowledge about early cognitive development, and assist in the establishment of definitions of normative development against which deviations can be evaluated.