Two experiments used procedures similar to those used by R. L. Greene (1989) to test the 2-process theory of the spacing effect and, in particular, the contextual-variability subtheory that applies to free-recall performance. Experiment 1 obtained a spacing effect in free recall following intentional learning but not following incidental learning, contrary to a previous result supporting the 2-process theory. Experiment 2 replicated the incidental-learning results when a slow presentation rate was used. However, with a faster presentation rate, a spacing effect was obtained, and performance exceeded that of the slow-presentation-rate condition at the longest lag. Neither the contextual-variability subtheory of 2-process theory nor an alternative deficient-processing hypothesis was able to account for all of the data. 1 Greene (1989) labeled this hypothesis the study-phase-retrieval subtheory. However, we do not use this term, in order to focus on the nature of the underlying explanatory mechanism involving contextual variability and to avoid confusion with another class of theories that is discussed later in the article.

Three experiments investigated feature quantity and semantic quality accounts for level of processing effects on face recognition. Experiment 1 established that as the "level of processing" of a face judgment increased, the number of eye movements and inspection time increased, and subsequent recognition performance (recognition and recognition response time) improved. Experiment 2 found that, with the number of eye movements and inspection time held constant, as the "level of processing" of a face judgment increased subjects' cognitive level of processing (assessed by task-evoked peak pupillary dilation) increased, but recognition performance did not improve. Experiment 3 indicated that, with the number of eye movements held constant, recognition performance did not improve as a function of inspection time. These findings are consistent with a feature quantity hypothesis.Experiment 1 is based on an independent study completed at Gettysburg College by Lance C. Bloom and was presented at the 61st Annual Meeting of the Eastern Psychological Association in Philadelphia, April 1, 1990.We thank Dr. Robert Bornstein for his advice, encouragement, and helpful comments on earlier drafts of this article; Robert Crowder, Geoffrey Loftus, Keith Rayner, and Don Read for helpful comments on earlier drafts of this article; Marion Willetts-Bloom for comments on earlier drafts of this article and assistance in procedure development in Experiment 1; Amy Kale and Elizabeth Peabody for assistance in scoring data; Wayne Wolfe for overseeing the construction of slide materials; and Sharon Emmons for figure consulting and engineering.

The suffix effect is the reduction in the recallability of the last few items of a just-spoken list caused by appending a nominally irrelevant item, or suffix. The effect is widely assumed to comprise a "structural" terminal component, affecting just the last item, and a strategy-sensitive preterminal component. In a series of 8 experiments, the authors fail to replicate any of a variety of findings widely cited as the empirical basis for this 2-component theory. The authors also question the support that earlier findings provide for the theory, even if they had proved replicable. They attribute the entire suffix effect to the grouping of the suffix with the list items.

The suffix effect is the selective impairment in recall of the final items of a spoken list when the list is followed by a nominally irrelevant speech item, or suffix. It is widely assumed to comprise a bottomup, or structural, effect restricted to the terminal item and a top-down, or conceptually sensitive, effect confined to the preterminal items. Reported here are eight experiments that challenge this view by demonstrating that the terminal suffix effect, as well as the preterminal suffix effect, is susceptible to conceptual influence. The entire suffix effect may be better conceived of as a phenomenon arising from perceptual grouping.

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