Introduction: The following study investigates relationships between spaced practice (re-studying after a delay) and transfer of learning. Specifically, the impact on learners ability to transfer learning after participating in spaced model-building or unstructured study of narrated text. Method: Subjects were randomly assigned either to a model-building or a free study group. All subjects completed a pre-test of topic knowledge. In addition, participants in the model-building group watched a short demonstration of the model-building task. Participants listened to passages and either built a model or studied a transcript of the narration at increasing time lags. Finally, participants wrote a test of memory for detail and an extension test of knowledge transfer. Results: Knowledge transfer test scores improved for the model-building group as time lag between encoding and restudy increased. No effect was found between time lags in the free study group. No statistically detectable time lag affect was found for the detail test. Discussion: The following study provides evidence of improved knowledge transfer resulting from elaborate constructive model-building. When participants' study methods were unstructured transfer did not statistically detectably improve as time lags increased between study intervals. (Contains 1 figure.)