Prior knowledge: The effects of natural category size on memory for implicitly encoded concepts.

Studying a familiar word activates its associates, and these associates affect the likelihood of recalling the studied word in a cued recall task. These experiments examined variables that normally affect memory for the studied word to determine if they have similar effects on memory for the word's associates. Memory for associates was tested by cued recall (Experiments 1–3) or by recognition (Experiments 4–5), with the number and strength of the associates varied in all experiments. In different experiments, test instructions (direct–indirect), distractor tasks, lag, and amount of practice were manipulated. Provided that subjects were not distracted prior to test, the probability of recalling associates of the studied word decreased with the number of associates activated and with their strength under all conditions. The strength of the associates but not their number affected recognition. In general, variables that affected recall and recognition of studied words had parallel effects on their associates. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Negative recency and levels of processing in free recall.

Compared initial and final free recall of 5-item lists for 4 different "processing activities"; during list presentation 32 undergraduates either silently rehearsed, overtly rehearsed, generated rhymes, or generated verbal associates. Whereas the 2 rehearsal conditions showed a marked superiority in immediate free recall, their final (delayed) recall was inferior to that of lists for which associates were generated. It appears that the negative recency effect commonly obtained in delayed recall is a consequence of processing strategies which maximize the recency effect in immediate recall. (French summary) (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Multicentre survey of the comparative in-vitro activity of piperacillin/tazobactam against bacteria from hospitalized patients in the British Isles

In five experiments, in which subjects were to identify a target word as it was gradually clarified, we manipulated the target's frequency of occurrence in the language and its neighborhood size--the number of words that can be constructed from a target word by changing one letter, while preserving letter position. In Experiments 1-4, visual identification performance to screen-fragmented words was measured. In Experiments 1 and 2, we used the ascending method of limits, whereas Experiments 3 and 4 presented a fixed-level fragment. In Experiment 1, there was no relation between overall accuracy and neighborhood size for words between three and six letters in length. However, more errors of commission (guesses) were made for high-neighborhood words and more errors of omission (blanks) were made for low-neighborhood words. Letter errors within guesses occurred at serial positions having many neighbors, and these positions were also likely to contain consonants rather than vowels. In Experiment 2, a small facilitatory effect of neighborhood size on both high- and low-frequency words was found. In contrast, in Experiments 3 and 4, using the same set of words, inhibitory effects of neighborhood size, but only for low-frequency words, were found. Experiment 5, using a speeded identification task, showed results parallel to those of Experiments 3 and 4. We suggest that whether neighborhood effects are facilitatory or inhibitory depends on whether feedback allows subjects to disconfirm initial hypotheses that the target is a high-frequency neighbor.     

Spatial and semantic priming effects in tests of spatial knowledge.

In eight experiments we investigated spatial and semantic priming effects. In Experiments 1 and 2, subjects made judgments about the locations of buildings on their campus and locations of states in the United States. We found that location judgments were faster when preceded by judgments about geographically near locations than by judgments about relatively far locations. In Experiments 3a, 3b, and 3c, subjects judged words as names of states of the United States or as nonstate words. No spatial priming effect was found in any experiment, nor was a priming effect found for nonstate words preceded by semantically related words. Experiment 4 compared spatial priming in a state–nonstate classification with a state-plus-location classification task. Spatial priming was found in the latter but not the former. These results are interpreted with an account that treats spatial and nonspatial knowledge as separate structures. Using the nonstate words of Experiment 3c, Experiments 5a and 5b together demonstrated semantic priming in a lexical decision task. The semantic priming results are interpreted with a postlexical checking-strategy account of semantic priming. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Aging and implementation of encoding strategies in the generation of rhymes: The role of executive functions.

This experiment examines whether the age-related decrease in the generation effect of rhymes is mediated by executive functioning. Young and elderly adults read and generated pairs of rhyming words for subsequent recall. Participants were also administered neuropsychological tests (executive and mnemonic functions). Results showed that elderly adults performed less well on the neuropsychological tests and benefited less than the younger participants from the generation effect. Hierarchical regression analyses revealed that the executive functions composite score was correlated with the generation effect and that it accounted for a large proportion of the age-related variance of the size of this measure. This finding supports the view that the age-related decrement in strategic encoding implementation is due to a decrease of executive functioning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The production effect: Delineation of a phenomenon.

In 8 recognition experiments, we investigated the production effect—the fact that producing a word aloud during study, relative to simply reading a word silently, improves explicit memory. Experiments 1, 2, and 3 showed the effect to be restricted to within-subject, mixed-list designs in which some individual words are spoken aloud at study. Because the effect was not evident when the same repeated manual or vocal overt response was made to some words (Experiment 4), producing a subset of studied words appears to provide additional unique and discriminative information for those words—they become distinctive. This interpretation is supported by observing a production effect in Experiment 5, in which some words were mouthed (i.e., articulated without speaking); in Experiment 6, in which the materials were pronounceable nonwords; and even in Experiment 7, in which the already robust generation effect was incremented by production. Experiment 8 incorporated a semantic judgment and showed that the production effect was not due to “lazy reading” of the words studied silently. The distinctiveness that accrues to the records of produced items at the time of study is useful at the time of test for discriminating these produced items from other items. The production effect represents a simple but quite powerful mechanism for improving memory for selected information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Word-fragment cuing: The lexical search hypothesis.

In four experiments we evaluated aspects of the hypothesis that word-fragment completion depends on the results of lexical but not semantic search. Experiment 1 showed that the number of meaningful associates linked to a studied word does not affect its recovery when the test cue consists of letters and spaces for missing letters. Experiments 2 and 3 showed retroactive interference effects in fragment completion when words in a second list were lexically related to words in a first list but not when the words in the second list were meaningfully related. Experiment 4 indicated that for studied words, instructions to search at the word level facilitated completion performance and that instructions to generate letters to fill missing spaces had no effect. Other findings indicate that completion was affected by the number of words lexically related to the fragment and by the number of letters missing from the fragment. In general, experimental manipulations that focused on lexical characteristics were effective, and those that focused on semantic characteristics were ineffective. The findings support the conclusion that word fragments engender a lexical search process that does not depend on retrieving encoded meaning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Familiarity and lexicality as determinants of the generation effect.

Two experiments addressed the question of whether representation in the mental lexicon is a sufficient condition for obtaining the generation effect. Contrary to an earlier report (Nairne, Pusen, & Widner, 1985), our experiments showed that low-frequency words did produce significant retention advantages when generated, but only when items were rated as highly familiar to the subjects; when low-frequency words were recognized as words but were rated low in familiarity, no generation effect emerged. Overall, our results support the position that lexical representation is neither a necessary nor a sufficient condition to produce the generation advantage. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Word recall in schizophrenia: a connectionist model

OBJECTIVE: The authors examined word recall of patients with schizophrenia by using an experimental paradigm generated from connectionist models of memory. METHOD: Schizophrenic patients and normal comparison subjects first studied and then recalled a list of 32 words of equal difficulty. Both the connectivity (associative strength) and the network size (number of associates) of the words varied in such a way that the list contained equal proportions of four types of words: 1) high connectivity-small network size, 2) low connectivity-small network size, 3) high connectivity-large network size, and 4) low connectivity-large network size. RESULTS: The schizophrenic patients recalled fewer words and showed a particularly pronounced effect of the connectivity of the to-be-remembered words. For the patients, regardless of network size, recall improved substantially for words of high connectivity and declined dramatically for words of low connectivity. By contrast, the comparison subjects showed the expected effects, with the best recall for words of high connectivity-small network size, followed by words of low connectivity-small network size, then by words of high connectivity-large network size, and finally by words of low connectivity-large network size. CONCLUSIONS: Schizophrenia may be characterized by faulty modulation of associative links within a putative lexicon that is thought to be widely distributed across frontal and temporal lobes.     

Encoding context and retrieval conditions as determinants of the effects of natural category size.

Studying a familiar word activates its associates in long-term memory. In the present experiments we manipulated the number of associates activated by words studied in the presence of unrelated context words, meaningfully related context words, or in the absence of modifying context words. Memory was tested by either cued or free recall. The results showed that the number of directly activated associates can facilitate, have no effect, or disrupt recall for studied words. The direction and magnitude of the effects of number of activated associates is shown to be determined by the encoding/retrieval context. Implications for the distinction between episodic and semantic memory are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Inhibiting word generation with word presentations.

The ability to generate words of a given category is found to be impaired when other words of the same category are being heard (Experiments 1–4). Little if any impairment arises from hearing words of a different category (Experiments 1, 2, and 3). This pattern of results occurs with categories defined both semantically (Experiments 1, 2, and 4) and graphemically (Experiment 3). The extent of the impairment is found to be comparable to that which occurs when other words of the same category are studied and recalled prior to generation (Experiment 4). These findings are discussed in the context of other inhibitory phenomena. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Failure to find the picture superiority effect in implicit conceptual memory tests.

According to the transfer appropriate processing framework (H. L. Roediger, M. S. Weldon, & B. A. Challis, 1989), if pictures engage more conceptual processing than words, then they should produce more priming on implicit conceptual tests. Experiments 1 and 2 did not find any significant advantage of pictures on the implicit category production or word association tests. When these tests were given as explicit cued-recall tests in Experiment 3, pictures were recalled better than words, producing a dissociation and indicating that the materials were sensitive to differences in picture and word processing. In Experiments 4 and 5, the implicit tests showed level-of-processing effects indicating that they were sensitive to differences in conceptual processing. Therefore, it is hypothesized that (a) conceptual processing plays a minor role, if any, in superior picture recall and that visual distinctiveness is a more important factor; and (b) distinctiveness is more important in intentional than incidental retrieval. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of repetition on associative recognition in young and older adults: Item and associative strengthening.

Young and older adults studied word pairs and later discriminated studied pairs from various types of foils including recombined word-pairs and foil pairs containing one or two previously unstudied words. We manipulated how many times a specific word pair was repeated (1 or 5) and how many different words were associated with a given word (1 or 5) to tease apart the effects of item familiarity from recollection of the association. Rather than making simple old/new judgments, subjects chose one of five responses: (a) Old-Old (original), (b) Old-Old (rearranged), (c) Old-New, (d) New-Old, (e) New-New. Veridical recollection was impaired in old age in all memory conditions. There was evidence for a higher rate of false recollection of rearranged pairs following exact repetition of study pairs in older but not younger adults. In contrast, older adults were not more susceptible to interference than young adults when one or both words of the pair had multiple competing associates. Older adults were just as able as young adults to use item familiarity to recognize which word of a foil was old. This pattern suggests that recollection problems in advanced age are because of a deficit in older adults' formation or retrieval of new associations in memory. A modeling simulation provided good fits to these data and offers a mechanistic explanation based on an age-related reduction of working memory. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Recall of associates generated to emotionally toned stimulus words.

Suggests that an explanation for differential recall can be found without recourse to an arousal model. Four experiments were conducted with 200 college students. Exp 1 replicated the findings of E. B. Jones et al (1987) that Ss show poor recall of associates to emotional words. Exp 2 showed that reducing the number of emotionally toned stimulus words in the word list resulted in an improvement in recall for associates generated to these words. In Exp 3, recall for associates generated to emotionally toned stimulus words was poorer if the stimulus words were similar in meaning than if they were dissimilar. Exp 4 found that stimulus word properties other than emotionality could be manipulated to demonstrate a differential recall. Results are explained in terms of the inability of the retrieval system to discriminate among competing sets of responses that are semantically and emotionally congruent. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of normal aging on the manipulation of information in working memory

The goal of this study is to examine the central executive of working memory in normal aging, specifically focusing on its capacities to manipulate or modify the format of the to-be-recalled material. The central executive was measured with the alphabetical span procedure, during which subjects were asked to recall a random series of words in their alphabetical order. The storage demand was equalized across subjects by adjusting the list lengths according to individual span. Experiments 1, 2, and 3 showed that elderly subjects were not impaired in manipulating information, relative to young controls, even when the difficulty of the task was increased. In Experiment 4, validity was tested by asking young subjects to perform the task under the conditions of full or divided attention. Alphabetical recall was more impaired than direct recall during the divided attention condition, which suggests a larger involvement of the central executive component in the former. These results are discussed in relation to the hypothesis of a central executive impairment being associated with normal aging.     

Memory disadvantages for CVC associates of emotional words

A paired-associate task (word-CVC) performed by 40 subjects confirmed that associates to active emotional words were less well remembered than associates to neutral words or pleasant or unpleasant ones. Results are interpreted as satisfactorily explained by differences in the activation of network nodes if such differences were in turn affected by the arousal characteristic of the words.     

Single word production in English: The role of subsyllabic units during phonological encoding.

Five experiments investigated the role of sublexical units in English single word production L. Ferrand, J. Segui, and G. W. Humphreys (1997) reported a priming effect that was most effective when primes and targets shared the first syllable. Experiments 1A and 1B failed to replicate this effect but Experiment 1B showed that subsyllabic units play a role in speech production. This role was further explored using a picture naming task in Experiment 2. Naming latencies were shortest when the segmental overlap between prime and target (picture name) was largest, regardless of the syllable structure of the target. Experiments 3 and 4 replicated this segmental overlap effect with different sets of words as targets. Experiment 5 showed that the magnitude of the overlap effect increased with longer prime exposure duration. The implications of these results for theories of phonological encoding in speech production are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Aging and the stability of activation and sampling in cued recall.

Age effects in cued recall were investigated as a function of activation and sampling of preexisting associates of the test cue. Young adults, community-dwelling elderly, and elderly patients studied lists of unrelated words and were tested with extralist cues. Preexperimental strength between test cues and studied words was manipulated to discern differences in activation, and normative size of the set of associates was manipulated to discern differences in sampling. Test delay and prior testing were also manipulated in Exp 1. Although large age effects were found with phonemic and taxonomic test cues, young and older Ss showed comparable effects of strength and set size, suggesting that age effects were not due to activation and sampling differences. Test delay and prior testing also had comparable effects. Implications for age effects in episodic cued recall are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dimensions of mood in mood-dependent memory

In this investigation of the roles of 2 different dimensions of mood (pleasantness and arousal) in mood-dependent memory (MDM), participants generated words while listening to a selection of independently rated mood music (normative study and Experiment 5). Then they recalled the words while listening to another mood-music selection (Experiments 1-3) or to a verbal-mood scenario (Experiment 4). Changing only the dimension of mood pleasantness from generation to recall decreased memory whether the intended moods were explicitly defined or not. However, changing only arousal decreased memory only when moods were defined. Thus, pleasantness-dependent memory, but not arousal-dependent memory, occurred consistently. Although MDM also occurred with simultaneous changes in both dimensions, the effect was not significantly greater than that of pleasantness-dependent memory. The results are discussed in terms of 2-dimensional theories of emotion as applied to memory.     

On the nonautomaticity of visual word processing: Electrophysiological evidence that word processing requires central attention.

The present study used event-related potentials (ERPs) to determine the degree to which people can process words while devoting central attention to another task. Experiments 1-4 measured the N400 effect, which is sensitive to the degree of mismatch between a word and the current semantic context. Experiment 5 measured the P3 difference between low- and high-frequency words. Because these effects can occur only if a word has been identified, both ERP components index word processing. The authors found that the N400 effect (Experiments 1, 3, and 4) and the P3 difference (Experiment 5) were strongly attenuated for Task 2 words presented nearly simultaneously with Task 1. No such attenuation was found when the Task 1 stimulus was presented but required no response (Experiment 2). Strong attenuation was also evident when the Task 2 word was presented before the Task 1 stimulus (Experiment 4), suggesting that central resources are not allocated to stimuli first-come, first-served but rather are strategically locked to Task 1. The authors conclude that visual word processing is not fully automatic but rather requires access to limited central attentional resources. (PsycINFO Database Record (c) 2010 APA, all rights reserved)