States that recall of items given spaced repetitions is generally superior to recall of items given immediate repetitions. Reports on a test of Jacobi's hypothesis that this spacing effect is explained by the distinction between problem solving and remembering. Suggests that the effect cannot be explained solely by this distinction. (Author/MES)

A Bayesian statistical procedure separating storage from retrieval was used to study development and release of proactive interference in the Brown-Peterson paradigm. A theory of PI is developed stressing response competition at test time and interference in transfer between short- and long-term memory. (CHK)

The guessing-bias and proactive interference hypotheses of the Ranschburg Effect were investigated by giving three groups different instructions as to guessing during recall. Results failed to support the prediction that the effect should be reduced or eliminated on shift trials. Neither hypothesis received significant support. (CHK)