The results of studies intended to replicate the enhancement of spatial-temporal reasoning following exposure to 10 min. of Mozart's Sonata for Two Pianos in D Major (K.448) have been varied. While some studies have replicated the effect, others have not. We suggest that researchers' diverse choice of dependent measures may account for these varied results. This paper provides a neurophysiological context for the enhancement and considers theoretical and experimental factors, including the choice of dependent measures, the presentation order of the conditions, the selection of the musical composition, and the inclusion of a distractor task, that may contribute to the various findings. More work is needed before practical applications can be derived.