Over the past twenty years numerous studies have investigated the extent to which morphological constituents of words are activated during the process of word recognition. In the vast majority of these studies it has been assumed that a correspondence exists between the formal linguistic analysis of a word and its representation in the minds of native speakers. This paper investigates the the extent to which this correspondence can be affected by individual variation that is associated with education, exposure and training. We investigated student who had recently completed a course in medical terminology. These students, and matched control subjects, responded to medical and nonmedical multimorphemic stimuli in a lexical decision task. The results indicate that the medical terminology students' training affected their performance on novel medical words as well as their performance on very common medical words (e.g., psychiatry) that would have been part of their vocabulary prior to taking the course. The results therefore support the view that automatic unconscious lexical processing can indeed be modified by explicit training and specialized exposure. This finding has consequences for the generalizability of studies conducted on university students to the general population of native speakers.