A number of independent lines of research have suggested that semantic and articulatory information become available differentially from pictures and words. The first of the experiments reported here sought to clarify the time course by which information about pictures and words becomes available by considering the pattern of interference generated when incongruent pictures and words are presented simultaneously in a Stroop-like situation. Previous investigators report that picture naming is easily disrupted by the presence of a distracting word but that word naming is relatively immune to interference from an incongruent picture. Under the assumption that information available from a completed process may disrupt an ongoing process, these results suggest that words access articulatory information more rapidly than do pictures. Experiment 1 extended this paradigm by requiring subjects to verify the category of the target stimulus. In accordance with the hypothesis that picture access the semantic code more rapidly than words, there was a reversal in the interference pattern: Word categorization suffered considerable disruption, whereas picture categorization was minimally affected by the presence of an incongruent word. Experiment 2 sought to further test the hypothesis that access to semantic and articulatory codes is different for pictures and words by examining memory for those items following naming or categorization. Categorized words were better recognized than named words, whereas the reverse was true for pictures, a result which suggests that picture naming involves more extensive processing than picture categorization. Experiment 3 replicated this result under conditions in which viewing time was held constant. The last experiment extended the investigation of memory differences to a situation in which subjects were required to generate the superordinate category name. Here, memory for categorized pictures was as good as memory for named pictures. Category generation also influenced memory for words, memory performance being superior to that following a yes--no verification of category membership. These experiments suggest a model of information access whereby pictures access semantic information were readily than name information, with the reverse being true for words. Memory for both pictures and words was a function of the amount of processing required to access a particular type of information as well as the extent of response differentiation necessitated by the task.

It is well known that visual word recognition is influenced by context, word frequency, and stimulus quality. A processing account is outlined in which stimulus quality affects the orthographic input lexicon, whereas context influences both the orthographic input lexicon and the semantic system. Word frequency exerts its primary effects on the pathways that link lexical systems with each other and with the semantic system. Previous findings that are problematic for alternative models along with the results of two new experiments are consistent with this account.How does a reader recognize a printed word? When cognitive scientists are able to answer that question we will have made substantial progress in understanding the nature of mental representation and process. Although there are currently several competing models of visual word recognition such as Morton's (1969) logogen model, Rumelhart and

Two experiments examined how depth of processing on a contextual priming item affects (a) the amount of priming obtained in the processing of a target item in a lexical decision task (LDT) and (b) subsequent episodic memory for the prime and target items. Experiment 1, in which prime and target items were presented sequentially, yielded three main results: (a) The magnitude of the priming effect, measured by the difference between lexical decision times to word targets preceded by related and unrelated primes, increased as the depth of prime processing increased. (b) In an unexpected postsession recognition test, episodic memory for a prime was dependent on the depth to which it had been processed, whereas memory for a target was unaffected by the depth of processing that had occurred on its prime. (c) Episodic memory for both primes and targets was greater when they had appeared in related pairs rather than unrelated pairs in the LDT. However, unlike immediate contextual priming, the magnitude of the semantic relatedness effect in episodic recognition was not affected by level of processing. In Experiment 2 a two-word LDT was used in which a yes response was made only if two simultaneously presented letter strings were both words. Depth of processing was varied by using different types of nonword distractors: pronounceable nonwords, random letter strings, or strings of Xs. As in Experiment 1, priming was greater and episodic recognition was better, the deeper the level of processing that occurred in the LDT. Similarly, episodic recognition memory was greater for items that had appeared in related pairs in the LDT. Although these data suggest that similar processes modulate both contextual priming effects and episodic recognition, the dissociation in some conditions between the occurrence of contextual priming in the LDT and later relatedness effects in episodic recognition indicate that the underlying mechanisms are not identical.

In a variety of situations it has been observed that the processing of a verbal stimulus is facilitated when it is preceded by an associated word. This article is concerned with determining whether such facilitation occurs automatically upon prime presentation or whether facilitation depends on the manner of processing the prime. Experiment 1 demonstrated that a letter search in a target word was facilitated when the target was preceded by either an identical or semantically associated word. If, however, a letter search was required in the prime as well as in the target (Experiment 2), the relative advantage enjoyed by targets preceded by identical-word primes disappeared. Experiment 3 replicated this loss of facilitation using semantically associated word pairs. Contextual facilitation thus appears to depend upon the mode of analysis of the prime. If the prime is analyzed as a meaningful unit, facilitation occurs. If, however, it is subjected to a more discrete, letter-by-letter analysis, the priming effect vanishes.

When 2 stimuli are presented in rapid succession, reaction time to the 2nd stimulus is typically delayed. Various theories of this phenomenon, commonly referred to as the psychological refractory period, have been proposed. The theories have been placed into 3 categories: (a) central refractoriness theories, which postulate a refractoriness in the system following the 1st response selection; (b) preparatory state theories, which explain the delay in terms of the expectancy or readiness generated by the particular interstimulus intervals employed; and (c) single-channel theories, which assume a mechanism of limited capacity in the processing system. A review of the literature indicates that the latter theory best accounts for the available data. It is suggested that a limited capacity attention mechanism which is required for response selection may be the locus of the delay.