The transient information effect occurs when explanatory information disappears before it can be adequately processed and leads to inferior learning than more permanent sources of information. Two experiments, involving grade 10 students, investigated the impact of segmentation on a common form of transient information (spoken text) and a more permanent form of information (written text). It was found that segmenting text into smaller sections benefits both modalities. However, the largest impact of segmentation was found with the spoken text. Furthermore, evidence emerged that the written text led to superior learning than an identical spoken text. The overall results suggest that using long-spoken explanatory texts can have a negative impact on learning, unless transitory effects are reduced. Copyright © 2012 John Wiley & Sons, Ltd.