Predicting free recalls

This article reports some calculations on free-recall data from B. Murdock and J. Metcalfe (1978), with vocal rehearsal during the presentation of a list. Given the sequence of vocalizations, with the stimuli inserted in their proper places, it is possible to predict the subsequent sequence of recalls--the predictions taking the form of a probability distribution over all possible such sequences. The predictions are parameter free. This article looks at (a) the accuracy of those predictions and how that accuracy can be validated, (b) the principles on which the predictive algorithm is based, and (c) the limits to predictability. Some implications for the understanding of free recall are spelled out.