Figure 5.4 | Results for the Short-Term Memory Distractor Task | This figure shows how forgetting in short-term memory occurs over time. As the length of the distractor interval increases, forgetting increases very rapidly. In less than 30 seconds, recall is essentially zero.

(Data from: Peterson, L. R., & M. J. Peterson, M. J. (1959). Short-term retention of individual verbal items. Journal of Experimental Psychology, 58, 193–198.)