Manipulation of attention at study affects an explicit but not an implicit test of memory

We investigated the impact of attention during encoding on later retrieval. During study, participants read some words aloud (ignoring the print color) and named the print color of other words aloud (ignoring the word). Then one of two memory tests was administered. The explicit test--recognition--required conscious recollection of whether a word was studied. Previously read words were recognized more accurately than were previously color named words. This contrasted sharply with performance on the implicit test--repetition priming in lexical decision. Here, words that were color named during study showed priming equivalent to words that were read during study; both were responded to faster than unstudied words. Thus, an attentional manipulation during study had a strong effect on an explicit test of memory, but almost no effect on an implicit test. Focal attention during study is crucial for remembering consciously but not necessarily for remembering without awareness.     

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)     

Repetition priming effects for newly formed associations are perceptually based: Evidence from shallow encoding and format specificity.

This article is concerned with memory for newly formed associations as displayed on implicit and explicit tests of memory. After studying a list of word pairs, participants were shown the original intact pairs and pairs formed by recombining the original pairs. Pairs were simultaneously presented both at study and at test. In a lexical-decision task in which participants were asked to indicate whether both items were words, responses to intact pairs were faster than to recombined pairs. The size of this association-specific repetition effect was relatively unaffected by a levels-of-processing manipulation, indicating that conceptual processes did not likely contribute to the production of the effect. Furthermore, the effect was not produced when pairs were presented simultaneously at study but sequentially at test, thus highlighting the importance of format of presentation. Finally, in an explicit speeded-recognition task the size of the association-specific effect was largely affected by levels-of-processing manipulation and was revealed even under sequential test presentation suggesting that the associative repetition effects were not contaminated by conscious recollection.?.?.?.? (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Modality specificity of implicit memory for new associations.

In previous research we demonstrated that newly acquired associations between unrelated word pairs influence the magnitude of priming effects on word-completion tests. This phenomenon of implicit memory for new associations is observed only following semantic study elaboration. The present experiments reveal that implicit memory for new associations, though elaboration dependent, is also modality specific: Associative effects on a visual word-completion test were consistently reduced by study-test modality shifts. In contrast, explicit memory for new associations, as indexed by cued-recall performance, was uninfluenced by modality shifts. The modality effect on completion performance was eliminated when subjects were given brief visual preexposures to, or were required to construct visual images of, word pairs presented in auditory study conditions. The results pose a theoretical puzzle insofar as they indicate that within the domain of implicit memory, access to the products of elaborative processing depends on modality-specific, sensory-perceptual processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sublexical components in implicit memory for novel words.

Five experiments with 280 university students investigated the role of sublexical components in implicit memory for novel words. Priming on an implicit word judgment task occurred consistently for nonwords formed out of familiar linguistic components (morphemes and syllables) but minimally for nonwords formed out of unfamiliar pseudosyllabic components. This effect was dissociable from explicit memory and insensitive to changes in the surface features of the stimuli. Moreover, it depended on unitization of stimulus components as opposed to priming of individual components. Results are interpreted in terms of the activation and integration of prior linguistic knowledge and as evidence against the role of new (perceptual or episodic) representations in implicit memory for new information. (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)     

Direct comparison of two implicit memory tests: Word fragment and word stem completion.

In 3 experiments, the implicit memory tests of word fragment and word stem completion showed comparable effects over several variables: Study of words produced more priming than did study of pictures; no levels-of-processing effect occurred for words; more priming was obtained from pictures when Ss imaged the pictures' names than when they rated them for pleasantness; and forgetting rates were generally similar for the tests. A different pattern of results for the first 3 variables occurred under explicit test conditions with the same word fragments or word stems as cues. It is concluded that the 2 implicit tests are measuring a similar form of perceptual memory. Furthermore, it is argued that both tests are truly implicit because they meet the D. L. Schacter et al (1989) retrieval intentionality criterion: Levels of processing of words have a powerful effect on explicit versions of the tests but no effect on implicit versions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Selective effects of interference on implicit and explicit memory for new associations.

Examined the effects of interference manipulation on explicit and implicit memory for pairs of normatively unrelated words in 2 experiments, involving 128 undergraduates. Findings show that interference affected explicit memory, as indexed by performance on cued recall, pair matching, and modified free-recall tests, but it did not affect implicit memory, as indexed by performance on a word-completion test. This pattern of results complements several previous findings, including those of the present authors (see PA, Vol 73:12203 and 29150), on performance dissociations between explicit and implicit memory for new associations. (44 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of elaborative processing on implicit and explicit memory for new associations.

Explored the relation between elaborative processing and implicit memory for new associations (i.e., the phenomenon that priming effects on word-completion tests are influenced by newly acquired associations between normatively unrelated words) in 4 experiments, using a total of 240 undergraduates. Results indicate that implicit memory for new associations, like explicit memory, depended on encoding of meaningful relations between paired words in the study list. However, variations in degree and type of associative elaboration had a large effect on explicit memory, as revealed by performance on letter-cued recall and paired-associate tests, but had little effect on implicit memory, as revealed by performance on a word-completion test. Discussion focuses on the theoretical implications of the observed similarities and differences between implicit and explicit memory for new associations. (49 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Repetition priming for newly formed and preexisting associations: Perceptual and conceptual influences.

Three experiments demonstrate that association-specific repetition effects can be obtained for both newly formed and preexisting associations and that these effects are sensitive to modality of presentation. After studying a list of word pairs, participants were shown the original intact pairs and pairs formed by recombining the original pairs. In a lexical-decision task in which participants were asked to indicate whether both items were words, responses were faster to newly formed associations in the intact than in the recombined condition. This association-specific repetition priming effect was also observed for preexisting associations when a speeded relatedness judgment task was used. Both effects were found to be attenuated under cross-modal presentation. Finally, an explicit speeded recognition task revealed an associative effect that was not attenuated when modality was crossed for newly formed associations and was actually exaggerated for preexisting associations, suggesting that the repetition priming effects were not produced by conscious recollection. Results are discussed in terms of frameworks that are based either on perceptual representation systems or on a transfer-appropriate processing model. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Processing implicit and explicit representations.

Summarizes the results of a 15-yr research program dedicated to understanding how implicitly activated memories affect remembering and proposes a model for describing such influences. Implicit memories are manipulated by varying the number of associates preexperimentally linked to test cues or studied words. Assumptions of the model specify when implicit memories of various types are likely to contribute to performance in various tasks. The main assumptions are that encoding involves both explicit and implicit processing components and that these components provide mutually exclusive sources of information during testing. Experiments designed to evaluate the exclusivity assumption are reported, and implications of the findings for several theoretical frameworks are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Adult age differences in implicit and explicit memory: Time course and encoding effects.

Young and older adults were tested at three delays on word-stem completion or cued recall following semantic or structural word judgments. Identical three-letter stems were present at retrieval for both implicit (completion) and explicit (cued recall) tasks; only the intention to recall list words differed. The young adults outperformed the older adults on both implicit and explicit task at all test delays. Under some conditions, the older but not the young adults performed more poorly on cued recall than on stem completion, suggesting a possible failure to use implicitly available information to support explicit remembering. These results suggest that some forms of implicit memory decline with normal aging. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Intact implicit memory for newly formed verbal associations in amnesic patients following single study trials.

This study examines the ability of amnesic patients to recover newly formed associations implicitly after a single study trial. Fifteen amnesic patients with various etiologies studied pairs by forming a sentence containing both words. At test, all participants saw 40 intact pairs, 40 rearranged pairs, and 40 new words. All pairs appeared side by side both at study and at test. For the implicit lexical-decision task, 40 nonwords were intermixed with the other pairs, and participants indicated whether both items were words. For the explicit speeded recognition test, participants were asked to indicate whether both words had appeared at study. Despite being severely impaired on the explicit test, amnesic patients performed like healthy controls on the implicit test, with faster and more accurate responses to intact pairs than to recombined pairs. Contrary to existing theories, the results suggest that amnesic patients can form and retain new associations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Recognition memory for new associations: electrophysiological evidence for the role of recollection

The electrophysiological correlates of recognition memory for new associations were investigated in two experiments. In both experiments subjects first studied unrelated word pairs. At test, they were presented with old words in the same pairing as at study (same pairs), old words in a different pairing from study (rearranged pairs), and pairs of new words. In Experiment 1 the test requirement was to discriminate between old and new pairs and, for any pair judged old, to then judge whether the pair was the same or rearranged. In Experiment 2 the requirement was merely to discriminate between old and new pairs. Event-related potentials (ERPs) were recorded for correctly classified same, rearranged and new pairs. The ERPs elicited by same pairs exhibited a similar pattern of effects in both experiments. Relative to the ERPs to new pairs, these effects took the form of sustained positive shifts with two distinct scalp maxima, over the left temporo-parietal and right frontal scalp respectively. ERPs to rearranged pairs showed effects which were similar in scalp topography, but markedly smaller in magnitude. This pattern of ERP effects closely resembles that found previously for test items defined as recollected on the basis of their attracting a successful source judgement. The findings therefore suggest that associative recognition memory shares some of the recollective processes that are engaged by the requirement to retrieve contextual information about a study episode. The findings from Experiment 2 indicate that the processes associated with the recollection of associated pairs are engaged regardless of whether the retrieval of associative information is an explicit task requirement.     

Associative priming in word fragment completion: a dissociation between explicit and implicit retrieval processes

Three experiments investigated associative priming in word fragment completion. In associative priming, the study word that acts as a prime is semantically related in some way to the response word that the subject must produce or respond to at test. For example, a prime might be semantically related to the solution to its paired word fragment (e.g. study "VANILLA", solve fragment "-H-C--A-E" at test, solution is "CHOCOLATE"). Associative priming therefore differs from both repetition and conceptual priming, in which the studied primes are themselves the words that must be produced or responded to at test. In Experiment 1, associative primes were found to influence word fragment completion performance on an explicit test, but not on an implicit test. Experiment 2 demonstrated that the effects of associative primes on explicitly instructed fragment completion cannot be attributed to the specific information about cue-prime relationships that is included in the explicit instructions. Experiment 3 demonstrated that a manipulation of modality, a variable known to disrupt implicit retrieval processes, disrupts repetition priming on an explicit test, but not associative priming. The results of these three experiments suggest that whereas repetition primes are retrieved from memory by both explicit and implicit retrieval processes, associative primes are retrieved by only explicit processes. These data suggest that implicit retrieval processes are cue-dependent processes which automatically retrieve memory information that provides a good match to retrieval cues. Explicit retrieval processes are cue-independent, functioning as an intentional retrieval set to access particular categories or types of memory information.     

Comparing word fragment completion and cued recall with letter cues.

Cued recall with word stems as cues and fragment completion rely on different types of letter cues and also differ in the explicit–implicit nature of the retrieval orientation. Despite these differences, variables effective in one task may be effective in the other because both rely on letter cues. Two variables known to affect cued recall were manipulated: Lexical set size (number of words that fit the letter cue) and meaning set size (number of associates generated to the studied words). Across four experiments, subjects in each task were less likely to recover targets from larger lexical sets. However, meaning set size affected cued recall but not fragment completion. These results indicate that fragment completion and letter-cued recall are based on lexical search but that cued recall also involves a semantic search component. Furthermore, type of retrieval cue had a greater effect than type of retrieval orientation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Developmental differences in implicit and explicit memory performance

Performance of preschool, elementary school, and college students was compared on a series of perceptual and conceptual implicit and explicit memory tasks that followed perceptual or conceptual processing during study. As expected, performance on the conceptual explicit memory task improved across age groups. In contrast, performance on the perceptual explicit memory task as well as that on both types of implicit memory tasks showed no developmental change. Also, perceptual processing during study led to better memory performance than conceptual processing for both the perceptual implicit and perceptual explicit tasks and conceptual processing during study led to better memory performance on the conceptual explicit memory task. Performance on the conceptual implicit memory task, in contrast, was affected equally by both types of study processing. The results are discussed in terms of transfer-appropriate processing (Roediger & Blaxton, 1987b) and unitization and grouping processes (Graf & Schacter, 1989).     

Unconscious mood-congruent memory bias in depression.

The purpose of this study was to investigate an unconscious or implicit mood-congruent memory (MCM) bias in clinical depression. Many studies have shown an explicit memory bias, but no study has yet found an implicit MCM bias in clinical depression. The authors compared depressed and control group participants on a conceptually driven implicit memory test. After studying words of positive, neutral, and negative affective valences, participants produced free associations to various cues. Implicit memory or priming was demonstrated by the production of more studied than unstudied words to the association cues. Depressed participants showed more priming of negative words, whereas controls showed more priming of positive words, thus supporting the MCM pattern. Also, no implicit memory deficit was found in depressed participants. These findings are discussed in the context of several prominent theories of cognition and depression. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On the implicit learning of novel associations by amnesic patients and normal subjects.

Examined whether amnesic patients and normal Ss can acquire novel associations implicitly and whether such learning can occur rapidly in a single trial. In 2 experiments, Ss studied novel word pairs either once or multiple times and were then asked to read old, new, and recombined word pairs as quickly as possible. In this paradigm, the learning of novel associations would be indicated by slower reading times for recombined word pairs than for old word pairs. In a 3rd experiment, a perceptual identification paradigm was used to assess implicit learning of new associations. One-trial learning of new associations was not observed in the 1st 2 experiments, but learning of new associations did occur after multiple learning trials. An advantage of old vs recombined word pairs was obtained after a single trial only in Exp 3 (using perceptual identification) when the results were combined across S groups. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Implicit and explicit memory in amnesia: An analysis of data-driven and conceptually driven processes.

The extent to which data-driven and conceptually driven processing determines amnesic patients' differential performance on implicit and explicit tasks was investigated. In 2 data-driven tasks, words that looked visually similar to target words were used as cues for a graphemic production task (implicit) and a graphemic cued-recall task (explicit). In 2 conceptually driven tasks, words semantically related to the target words were used as cues for both a production task and a cued-recall task. The nature of the task instructions consistently determined amnesic patient performance, regardless of the nature of the processing required. Thus, the distinction between implicit and explicit tasks captured the performance of amnesic patients better than did the distinction between data-driven and conceptually driven processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)