Imagery and concreteness norms and percentage noun usage were obtained on the 1,080 verbal items from the Toronto Word Pool. Imagery was defined as the rated ease with which a word aroused a mental image, and concreteness was defined in relation to level of abstraction. The degree to which a word was functionally a noun was estimated in a sentence generation task. The mean and standard deviation of the imagery and concreteness ratings for each item are reported together with letter and printed frequency counts for the words and indications of sex differences in the ratings. Additional data in the norms include a grammatical function code derived from dictionary definitions, a percent noun judgment, indexes of statistical approximation to English, and an orthographic neighbor ratio. Validity estimates for the imagery and concreteness ratings are derived from comparisons with scale values drawn from the Paivio, Yuille, and Madigan (1968) noun pool and the Toglia and Battig (1978) norms.The Toronto Word Pool (TWP) is a collection of 1,080 common English words originally selected from the Thorndike-Lorge (1944) word counts (see Murdock, 1968Murdock, , 1974. This pool has been used for some time in a number of laboratories in verbal learning, memory, and psycholinguistics studies, although normative data on the items have never been collected.In experiments that require random selection of a number of lists in order to exclude list-specific effects or to assure sufficient sampling of materials, it is particularly useful to have normative data available. Thus, information on item frequency allows lists to be matched or balanced on this variable. Similarly, if a moderate

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.

Two versions of a distributed-memory model, one for associative information and one for serial-order information, leave open the question of whether there are two different modes of operation or only one. An analysis of these two versions showed that differential predictions emerge when one considers the role of item information. To test these predictions, a standard item-recognition task (Sternberg, 1966) was embedded in a paired-associate probe-recognition task, a serial-order probe-recognition task, or both. The item-recognition serial-position curves were quite different in the paired-associate and the serial-order conditions, and followed the paired-associate condition when the two were combined. In general, the results were consistent with the predictions of the distributed-memory models, and supported the idea of different modes of operation rather than a single commonmode of operation. When trying to understand memory, it is useful to distinguish between item, associative, and serialorder information. Item information underlies recognition and associative information underlies pairwise associations, whereas serial-order information preserves the sequence of events. Further explanation and evidence in support of these distinctions may be found in Murdock (1974). Recently, two versions of a distributed memory model have been proposed, one for associative information (Murdock, 1982) and one for serial-order information (Murdock, 1983). Both use convolution and correlation as the storage and retrieval operations, both apply to recall and recognition, and both include item information. In the serial-order model, items and running pairs (A-B, B-C, C-D, ...) are stored, and in the associative model, items and discrete pairs (A-B, C-D, E-F, ...) are stored. In both models, the items (A, B, C, ...) are stored along with the (sequential or simultaneous) pairs. In both models, information is represented by random vectors. These are vectors whose elements are random variables. All information is stored in a common memory vector, M. In the associative model: where~is the memory vector after the jlh pair has been stored,~and 8i are the items comprising the jlh pairs, the asterisk (*) denotes convolution, the pro

In two experiments, subjects learned subspan and supraspan lists by sorting list items into subsets. An item recognition task followed, and reaction time was found to be a bilinear function of memory list length. The slope for supraspan lists was more shallow than the slope for subspan lists. The reaction time data for supraspan lists was replotted as a function of the number of subsets formed during the sorting task. Reaction time increased linearly with the number of subsets but was independent of the number of items within a tested subset. These results suggest that processing of information is serial between, but not within, organized subgroups.

Two experiments investigated the effect of performance feedback when testing recognition memory for short prememorized lists. Subjects were provided with either response-accuracy or response-latency feedback on a trial-by-trial basis. Payoff in both conditions depended solely upon accuracy performance. Subjects familiarized with their latencies responded faster than subjects given only accuracy feedback. There was no speed-accuracy trade-off. These results are discussed with reference to similar data from the choice reaction-time task. It is concluded that failure to provide subjects with adequate feedback on all aspects of this task is a serious oversight. This oversight is particularly surprising in those designs focusing upon speed.