In two experiments, several psychophysiological and verbal-report measures were recorded simultaneously in a single list-learning condition as indicants of a small number of hypothetical verbal information-processing constructs. The constructs studied were (a) rehearsal (type of processing), as measured in eye movements during study and with a self-report questionnaire; (b) processing intensity (task-induced activation), measured in terms of heart-rate and galvanic skin response (GSR) variability during study and with a self-report questionnaire; (c) recall from short-term store (STS); and (d) recall from long-term store (LTS). The recall constructs were measured with six standard verbal-recall performance measures, representing three theoretical distinctions between STS and LTS recall. Alternative models of individual differences, which specified the nature of these four constructs and their functional interrelations in terms of the observable measures, were evaluated, and a number of predictions made by contemporary theories of verbal learning were assessed. Mathematical identification of the models, statistical estimation of the parameters, and testing of goodness of fit were all based on the standard maximum-likelihood approach. ' In Experiment 1, analyses confirmed a dual-process conception of memory recall (STS, LTS) to be plausible, whereas a uniprocess model (single memory continuum) of the type proposed by Melton was rejected. The results of the second experiment provided a replication of Experiment 1 and also revealed that, independently of the j type of rehearsal, the "intensity" with which a subject studies is associated with an enhancement of LTS recall, but not STS recall. These results bear upon the question of process dualism in memory and upon the question of whether subject activation affects memory performance independently of the type of rehearsal. In addition, these results demonstrate that precise physiological measurement and self-report are viable means for quantifying complex study behavior, and that individual differences among subjects in verbal list-learning performance can be explained substantially by knowledge of specific cognitive processes.