The memory enhancement effect of emotion is absent in conceptual implicit memory.

Memory for emotional stimuli is superior to memory for neutral stimuli. This study investigated whether this memory advantage is present in implicit memory. Memory was tested with a test of explicit memory (associate cued recall) and a test of conceptual implicit memory (free association) identical in all respects apart from the retrieval instructions. After studying emotional and neutral paired associates, participants saw the first member of the pair, the cue; in the test of explicit memory participants were instructed to recall the associate; in the test of implicit memory participants were instructed to generate the first word coming to mind associated to the word. Depth of study processing dissociated performance in the tests, confirming that the free-association test was not contaminated by an intentional retrieval strategy. Emotional pairs were better recalled than neutral pairs in the test of explicit memory but not in the equivalent test of implicit memory. The absence of an emotion effect in implicit memory implies that emotional material does not have a privileged global mnemonic status; intentional retrieval is necessary for observing the emotion-related memory advantage. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evidence for multiple mechanisms of conceptual priming on implicit memory tests.

The authors examined effects of encoding manipulations on 4 conceptual implicit memory tasks: word-cued association, category-cued association, category verification, and abstract concrete classification. Study-phase conceptual elaboration enhanced priming for word-cued association with weakly associated words (Experiment 3), and for category-cued association with high- and low-dominance exemplars (Experiments 4 and 5), but did not enhance priming for word-cued association with strongly associated words (Experiments 1 and 2), for category verification with high- and low-dominance exemplars (Experiment 5), or for abstract/concrete classification (Experiment 7). Forms of priming that were unaffected by conceptual elaboration were not mediated by perceptual processes because they were unaffected by study-test modality changes (Experiments 6 and 8). The dissociative effects of conceptual elaboration on conceptual-implicit tasks suggest that at least 2 dissociable mechanisms mediate conceptual priming. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Midazolam amnesia and conceptual processing in implicit memory.

Prominent theories of implicit memory (D. Schacter, B. Church, & J. Treadwell, 1994) emphasize the dominant role of perceptual processing in mediating priming on perceptual implicit memory tests. Examinations of the effects of conceptual processing on perceptual implicit memory tests have produced ambiguous results. Although a number of investigations (e.g., J. Toth & R. Hunt, 1990) have demonstrated that variations in conceptual processing affect priming on perceptual implicit memory tests, these effects may arise because of the contaminating effects of explicit memory. The current experiment examined this controversy using midazolam, a benzodiazepine that produces a dense, albeit temporary, anterograde amnesia when injected prior to study. The experiment examined whether the effects of generation found on the implicit memory test of perceptual identification were affected by a midazolam injection prior to study. Results demonstrated that midazolam substantially diminished generation effects in free and cued recall, as well as overall performance on these tests, but had no detectable effect on the generation effect in perceptual identification. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Transfer effects in implicit tests of memory.

Anagram-solving tests were used to examine the durability and specificity of priming effects and the relation between repetition priming and skill-based facilitation. In 4 experiments, exposure to the solution of an anagram reduced the time required to solve it later, even after 2 wks. Facilitation varied with the correspondence between primes and the anagrams solved at test: priming was greatest for similar or identical anagrams, intermediate for items generated from fragment cues or read, and minimal for words presented aurally. In Exp 4, application of a newly acquired skill for solving a particular class of anagrams and item repetition had independent and additive effects. Overall, these results suggest that multiple component processes mediate facilitation on implicit memory tests. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Spacing effects on implicit memory tests.

The spacing effect refers to the advantage in memory for information that is repeated at separated points of time over information repeated in massed fashion. Spacing effects have been demonstrated on numerous explicit measures of memory. A series of experiments reported here demonstrate spacing effects on 3 implicit memory measures: (1) spelling of homophonic words, (2) word-fragment completion, and (3) perceptual identification. The spacing effect in perceptual identification was not found when materials were studied incidentally or when spacing was manipulated between lists. Also, whereas recognition of synonyms decreased as a function of spacing between synonyms, perceptual identification was uninfluenced by the spacing between synonyms. The results are interpreted as evidence that spacing effects on cued memory tests (both explicit and implicit) reflect optional rehearsal strategies. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Direct comparison of four implicit memory tests.

Four verbal implicit memory tests, word identification, word stem completion, word fragment completion, and anagram solution, were directly compared in 1 experiment and were contrasted with free recall. On all implicit tests, priming was greatest from prior visual presentation of words, less (but significant) from auditory presentation, and least from pictorial presentations. Typefont did not affect priming. In free recall, pictures were recalled better than words. The 4 implicit tests all largely index perceptual (lexical) operations in recognizing words, or visual word form representations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of imagery on perceptual implicit memory tests.

Four experiments demonstrate that imagery can promote priming on perceptual implicit memory tests. When Ss were given words during a study phase and asked to form mental images of corresponding pictures, more priming was obtained on a picture fragment identification test than from a study condition in which Ss performed semantic analyses of words. Imaginal priming of picture fragment identification occurred for recoverable fragments, but not for nonrecoverable fragments. The imagery effect was restricted to the imaged type of material: Imagining pictures (when presented with words) enhanced priming on a picture fragment identification test but not on word fragment completion. Similarly, when pictures were presented, imagining the corresponding words increased priming on word fragment completion but not on picture fragment identification. Overall, results support the hypothesis that imagining engages some of the same mechanisms used in perception and thereby produces priming. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Differential age effects for implicit and explicit conceptual associative memory.

Older adults show disproportionate declines in explicit memory for associative relative to item information. However, the source of these declines is still uncertain. One explanation is a generalized impairment in the processing of associative information. A second explanation is a more specialized impairment in the strategic, effortful recollection of associative information, leaving less effortful forms of associative retrieval preserved. Assessing implicit memory of new associations is a way to distinguish between these viewpoints. To date, mixed findings have emerged from studies of associative priming in aging. One factor that may account for the variability is whether the manipulations inadvertently involve strategic, explicit processes. In two experiments we present a novel paradigm of conceptual associative priming in which subjects make speeded associative judgments about unrelated objects. Using a size classification task, Experiment 1 showed equivalent associative priming between young and older adults. Experiment 2 generalized the results of Experiment 1 to an inside/outside classification task, while replicating the typical age-related impairment in associative but not item recognition. Taken together, the findings support the viewpoint that older adults can incidentally encode and retrieve new meaningful associations despite difficulty with the intentional recollection of the same information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Subjective qualities of memories associated with the picture superiority effect in schizophrenia.

Patients with schizophrenia (n=24) matched with 24 normal subjects were presented with both words and pictures. On a recognition memory task, they were asked to give remember, know, or guess responses to items that were recognized on the basis of conscious recollection, familiarity, or guessing, respectively. Compared with normal subjects, patients exhibited a lower picture superiority effect selectively related to remember responses. Unlike normal subjects, they did not exhibit any word superiority effect in relation to guess responses; this explains why the overall picture superiority effect appeared to be intact. These results emphasize the need to take into account the subjective states of awareness when analyzing memory impairments in schizophrenia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Serial position effects in implicit and explicit tests of memory.

The effects of serial position at study on implicit and explicit tests of memory were investigated. Both primacy and recency effects were observed in implicit tests of word-stem completion. These effects, however, were transient. No serial position effects were found in the 2nd half of testing (Exps 1 and 3) or when testing followed a 1-min, filled delay (Exp 2). Serial position effects were also examined on explicit tests of cued recall. When performance on explicit cued recall was below ceiling levels, a primacy effect persisted throughout testing (Exp 3). Similarly, in explicit tests of free recall, primacy effects were consistently observed, both with immediate testing (Exps 1 and 3) and when testing followed a filled delay (Exp 2). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Contributions of surface and conceptual information to performance on implicit and explicit memory tasks.

Four experiments examined the effects of perceptual and conceptual processing operations on 2 implicit and 2 explicit memory tasks. Results show an advantage of visual over auditory presentation for word-fragment completion, word-stem completion, and word-stem cued recall; there was no such advantage in recognition memory. Conceptual processing had no effect on the implicit tasks, a small effect on word-stem cued recall, and a large effect on recognition. It is concluded that there is no necessary trade-off between the 2 types of information. Speculatively, the use of perceptual information may be all or none and relatively automatic, whereas the use of conceptual information appears to be graded and more under conscious control. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of color and pattern on implicit and explicit picture memory.

The degree to which repetition priming is perceptually specific is informative about the mechanisms of implicit memory as well as of perceptual processing. In 2 sets of experiments with pictures as stimuli, we tested the effects of color and pattern manipulations between study and test on implicit memory (i.e., naming facilitation) and explicit memory (i.e., 2 forms of recognition). These manipulations did not affect priming. However, participants were able to explicitly detect stimulus changes at above-change levels. changes in color also produced small decrements in participants' ability to judge that repeated stimuli were old on a recognition tests. Experiment 2 showed diminished priming with changes in the stimulus exemplar (i.e., a different picture of the same named object) from study to test, which demonstrated that the picture-naming paradigm is sensitive to changes in physical attributes. The results suggest that physical attributes that are not essential to the formation of a shape representation do not influence repetition priming in a basic identification paradigm. Suggestions for how priming may be mediated are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Differential effects of aging and Alzheimer's disease on conceptual implicit and explicit memory.

The effects of aging and Alzheimer's disease (AD) on conceptual explicit and implicit memory were examined. Three groups of participants patients with AD; age-matched, older control participants; and younger control participants made deep (semantic) or shallow (nonsemantic) judgments about low-dominant category exemplars. Explicit memory was measured by category cued recall and implicit memory was measured by priming on a category-exemplar generation task. Younger participants had enhanced cued recall and priming following deep, relative to shallow, encoding; this indicated that both memory measures were conceptually driven. Aging reduced explicit, but not implicit, test performance, and it did not reduce conceptually driven processes for either test. In contrast, AD reduced explicit and implicit test performance, and it impaired conceptually driven memory processes for both tests. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of automatic associative activation on explicit and implicit memory tests.

Ss made either a graphemic or a semantic decision concerning word pairs during a study phase. Pair relatedness effects were observed in behavioral measures for the semantic task only, but a physiological measure (event-related potential) showed relatedness effects for both study tasks. Relatedness at study helped subsequent memory for tests involving word generation (fragment completion and cued recall). These effects were independent of those of the level of processing on memory. The results support P. Graf and G. Mandler's (1984) 2-process model of implicit and explicit remembering and demonstrate that automatically activated associations can have significant effects on both types of remembering. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The picture superiority effect in categorization: Visual or semantic?

Two experiments are reported whose aim was to replicate and generalize the results presented by J. G. Snodgrass and B. McCullough (1986) on the effect of visual similarity in the categorization process. For pictures, Snodgrass and McCullough's results were replicated because Ss took longer to discriminate elements from 2 categories when they were visually similar than when they were visually dissimilar. However, unlike Snodgrass and McCullough, an analogous increase was also observed for word stimuli. The pattern of results obtained here can be explained most parsimoniously with reference to the effect of semantic similarity, or semantic and visual relatedness, rather than to visual similarity alone. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Exact and conceptual repetition dissociate conceptual memory tests: Problems for transfer appropriate processing theory.

Tested whether a conceptual implicit memory test exhibited repetition effects similar to those found in free recall. 555 Ss participated in 3 experiments. In Exp 1, Ss rated a series of target words and their associates according to their degree of pleasantness in the implicit word-fragment completion and cued recall, and category cued and free recall tests. In Exp 2, Air Force recruits were tested on the category instance generation (CIG) and 4 additional tests in Exp 1. Exp 3 tested the Ss for CIG or category cued recall using instructions for relational process. Both CIG and category cued recall exhibited conceptual repetition effects. Category cued recall showed important differences between CIG and free recall. Theoretical implications are discussed. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Integration of orthographic, conceptual, and episodic information on implicit and explicit tests.

Examined how a prior encoding episode affected the integration of orthographic and conceptual information during incidental and intentional retrieval. 180 college students studied word lists with either shallow (counting vowels in each word) or deep (rating pleasantness) encoding tasks. Half of the Ss received implicit or explicit test instructions for a word fragment completion test containing orthographic cues (letters) and semantically related words. In the implicit condition, the word fragments had to be completed, while the explicit condition involved a memory test for the words seen earlier. On both the implicit and explicit tests, performance improved with an increase in the number of letters and words. Conceptual information processing had a larger effect in intentional retrieval than in incidental retrieval. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Directed forgetting in implicit and explicit memory tests: A comparison of methods.

Directed forgetting has been studied by instructing Ss to forget either (1) an initial list or (2) individually selected words. Differential encoding was hypothesized to be responsible for word-method directed forgetting, and retrieval inhibition for list-method directed forgetting. In Exps 1 and 2, directed forgetting was observed in recognition with the word method but not with the list method. Release from directed forgetting occurred in final recall after recognition but only with the list method. These results are interpreted in terms of a theoretical framework that integrates distinctive-relational processing theory with revised generation-recognition theory. In Exps 1–3, predictions from that framework were generally well supported on implicit and explicit retention tests that provided the same stimulus conditions. Consistent with processing theory, list-method directed forgetting was absent on data-driven or conceptually driven implicit tests, and word-method directed forgetting was absent on data-driven implicit tests. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Limitations of the distinctions between conceptual and perceptual implicit memory: A study of Alzheimer's disease.

Previous studies suggested that perceptual implicit memory is spared in Alzheimer's disease (AD) but conceptual implicit memory is not. This dissociation is often invoked to support views of implicit memory that distinguish between perceptual and conceptual processing or systems. This study investigated an alternate hypothesis: that methodological differences between perceptual and conceptual implicit tests could account for differences in performance. Fourteen AD participants, 16 elderly controls, and 16 younger controls participated in structurally parallel conceptual and perceptual tests of implicit memory that required production of studied items. Results showed normal perceptual and conceptual priming when participants with AD generated items at study but impaired priming in both tests when they merely repeated items. These results are inconsistent with both systems and processing views of implicit memory and suggest that similarity of study and test procedures is more important than the inferred theoretical construct. (PsycINFO Database Record (c) 2010 APA, all rights reserved)