Ribosomal RNA: a key to phylogeny

Subjects studied a list of words (e.g., cheetah) and received an implicit word fragment completion test (complete -h-t-h). On the test, the ratio of studied to nonstudied items (proportion overlap) was 0, 25, 50, 75, or 100%. Subjects were administered the identical test twice. Proportion overlap did not affect priming in word fragment completion, on either the first or second test. Also, the completion of studied and nonstudied fragments increased over repeated tests, but priming (the studied-nonstudied rate) remained unchanged. The proportion overlap of items between study and test does not affect performance on primed word fragment completion.     

Impaired priming on the general knowledge task in amnesia.

The status of priming on the general knowledge test was examined in amnesia. Twenty amnesic and 20 control participants studied words (e.g., CHEETAH) under semantic and nonsemantic encoding conditions and attempted to answer general knowledge questions (e.g., "What is the fastest animal on earth"?) under implicit and explicit retrieval instructions. The measure of memory was how many more test questions participants answered correctly using studied than nonstudied words. Amnesic patients showed impaired memory under implicit and explicit retrieval instructions. Control participants showed equal memory under implicit and explicit retrieval instructions, a result indicating that they engaged in explicit retrieval in both instruction conditions. General-knowledge priming appears to involve explicit retrieval that depends on medial-temporal and diencephalic regions damaged in amnesia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Differential sensitivity of perceptual identification for words and pseudowords to test expectations: Implications for the locus of word frequency effects.

Four experiments using a study-test paradigm provide evidence of differences in the nature of perceptual enhancement effects for words compared with results for meaningless pseudowords. Ss studied words (Exps 1, 2, and 4) or pseudowords (Exps 3 and 4) presented from 1 to 6 times in a list, then performed perceptual identification tests of studied and nonstudied items. Better identification of studied than of nonstudied items (i.e., a priming effect) was found for words and nonwords, but for words the function relating enhancement to the amount of prior exposure (i.e., a repetition effect) depended on whether Ss expected a later recall test. The results support dual-process accounts of word identification that assume a flexible use of either lexical code activation or episodic trace retrieval. A framework for understanding priming, repetition, and word frequency effects is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Level of processing affects priming in word fragment completion.

In 4 experiments, Ss studied words under learning conditions that promoted semantic or physical processing. An implicit word fragment completion test was administered (e.g., complete l ph t for elephant). When semantic and physical study conditions were manipulated between Ss (Exps 1 and 3) or within Ss in a blocked fashion (Exps 3 and 4), significant levels of processing (LOP) effects were obtained. When semantic and physical conditions were presented in a mixed list (Exps 2, 3, and 4), the LOP effect was smaller and not significant. A survey of the literature on LOP effects in implicit perceptual tests revealed that priming in these tests was consistently greater in the semantic than physical condition, with reports of statistically significant LOP effects. These findings contradict the widely held notion that LOP does not affect priming in implicit perceptual tests and have implications for contemporary accounts of performance in implicit and explicit measures of memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Generation and perceptual implicit memory: Different generation tasks produce different effects on perceptual priming.

The generation manipulation has been critical in delineating differences between implicit and explicit memory. In contrast to past research, the present experiments indicate that generating from a rhyme cue produces as much perceptual priming as does reading. This is demonstrated for 3 visual priming tasks: perceptual identification, word-fragment completion (WFC), and word-stem completion (WSC). This result occurred regardless of the mode of study response (written or spoken) or whether the generation condition was compared with reading words in or out of context. Rhyme generation did not produce priming on the letter height task (Masson & MacLeod, 2002), implying that the effect was not mediated by covert visualization. Nor was the effect due to the mere presence of the rhyme cue. Semantic generation (from definitions) produced a different pattern, exhibiting a reverse generation effect on WFC and WSC but full (read-level) priming on perceptual identification. The present results were not consistent with accounts based on the standard transfer-appropriate processing view, covert visualization, explicit contamination, or conceptual contributions to nominally perceptual tasks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

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.     

Explicit and implicit memory in the elderly: Evidence for double dissociation involving medial temporal- and frontal-lobe functions.

Groups of normal old people living in institutions or in the community and young adults were administered tests of implicit (IM) and explicit (EM) memory with word-stem (WSC) and word-fragment (WFC) completion paradigms. Neuropsychological tests sensitive to frontal and medial temporal lobe function were also administered. Age differences were observed on both tests of EM and on all neuropsychological tests. Priming effects on WSC were smaller in the institutionalized group than the other 2 groups. Comparisons of EM and IM test results with neuropsychological test scores revealed several effects, including significant correlations (a) between EM scores on both tests and performance on standard memory tests in both aged groups and (b) between IM scores of both aged groups on WSC and frontal-lobe test performance. The results provide evidence of a double dissociation with respect to involvement of brain regions in EM and IM. They also indicate that repetition priming in WSC and WFC involve different mechanisms and that frontal-lobe dysfunction is a factor in reduced priming on the WSC test. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dissociative effect of massed repetition on implicit and explicit measures of memory.

Ss saw or heard words presented once, or repeated 4 or 16 times in massed fashion, and then received an implicit or explicit memory test. Massed repetition did not increase priming on word fragment completion beyond that obtained from a single presentation but did enhance performance on various explicit tests (free recall, recognition, question cued recall, and word fragment cued recall) and an implicit general knowledge test. Modality of presentation affected implicit and explicit word fragment cued tests but did not affect performance on any of the other tests. Levels of processing affected performance on implicit and explicit question cued tests. These results are consistent with a transfer appropriate processing account of dissociations among memory measures and imply that massed repetition promotes conceptual processing but does not entail a repetition of perceptual-based processes responsible for priming on word fragment completion. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Implicit memory and test awareness.

In three experiments we examined whether normal subjects can perform an implicit test without becoming aware that the test items were previously encountered in the study phase of the experiment. Experiment 1 assessed single word priming with the stem completion task, and subjects who reported awareness/unawareness that the test items were previously encoded in the study task showed equivalent priming. Experiments 2a–c and 3 assessed associative priming with the stem completion task, and in this case, only subjects who were aware that the test items were previously encountered showed associative priming effects. These findings suggest that single word priming and associative priming reflect different memory processes because the former and not the latter effect can be observed in unaware subjects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The nature of word frequency effects on perceptual identification.

Four experiments, using a study–test paradigm, examined the effects of event presentation frequency on perceptual identification. In each cycle, subjects studied a list with different items presented from one to four or more times, then received identification tests of studied and nonstudied items. Pseudoword repetition (Experiments 1 and 4) produced a priming effect, that is, enhanced identification for presented items, and a repetition effect, that is, incremental improvements in identification for repeated items. In contrast, word repetition (Experiment 2, 3, and 4) produced priming but not repetition effects, a pattern that was not due to learning asymptotes or scaling distortions. We conclude that presentation frequency effects act on at least two distinct processing paths, selected on the basis of processing and task demands. Under conditions of simple exposure, perceptual enhancement is mediated, for codified events like words, primarily by nodal activation, and, for noncodified events like pseudowords, by information accumulation. (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)     

Effects of dividing attention on the memory-block effect.

S. M. Smith and D. R. Tindell (1997) reported that prior study of words that are orthographically similar to the solutions of test word fragments (e.g., studying ANALOGY and completing the fragment A L_ _GY, whose solution is ALLERGY) reduced the fragment completion rate relative to a baseline condition in which unrelated words were studied. They called this effect the memory-block effect. In the present experiment, the authors replicated this effect using a larger set of materials than that used by S. M. Smith and D. R. Tindell. The authors also found that dividing attention at study eliminated the memory-block effect. This pattern mimicked the effect of dividing attention on recognition memory but differed from the effect on repetition priming effects. The authors suggest that the memory-block effect is driven by a mechanism different from that responsible for producing repetition priming effects in an implicit fragment completion test. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The role of attention during encoding in implicit and explicit memory.

In 5 experiments, participants read study words under conditions of divided or full attention. Dividing attention reduced performance on the general knowledge test, a conceptual implicit test of memory. Likewise, dividing attention reduced conceptual priming on the word association task, as well as on a matched explicit test, associate-cued recall. In contrast, even very strong division of attention did not reduce perceptual priming on word-fragment completion, although it did reduce recall on the matched explicit test of word-fragment-cued recall. Finally, dividing attention reduced recall on the perceptual explicit tests of graphemic-cued recall and graphemic recognition. The results indicate that perceptual implicit tests rely minimally on attention-demanding encoding processes relative to other types of memory tests. The obtained pattern of dissociations is not readily accommodated by the transfer-appropriate-processing (TAP) account of implicit and explicit memory. Potential extensions of the TAP view are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Creating false memories: Remembering words not presented in lists.

Two experiments (modeled after J. Deese's 1959 study) revealed remarkable levels of false recall and false recognition in a list learning paradigm. In Exp 1, Ss studied lists of 12 words (e.g., bed, rest, awake); each list was composed of associates of 1 nonpresented word (e.g., sleep). On immediate free recall tests, the nonpresented associates were recalled 40% of the time and were later recognized with high confidence. In Exp 2, a false recall rate of 55% was obtained with an expanded set of lists, and on a later recognition test, Ss produced false alarms to these items at a rate comparable to the hit rate. The act of recall enhanced later remembering of both studied and nonstudied material. The results reveal a powerful illusion of memory: People remember events that never happened. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A transfer-appropriate processing account of context effects in word-fragment completion.

The claim that priming on implicit memory tasks such as word-fragment completion is sensitive to context effects was tested by using homographs (e.g., board) to manipulate context. On the basis of previous findings, it was assumed that presentation of only the perceptual cue at test (oa d) should activate the dominant meaning, thereby creating the same context for homographs encoded for their dominant encoding and a different context for homographs encoded for their nondominant meaning. As expected, little or no effect of varying context was observed on a perceptual implicit task (Experiments 1–2B). When explicit retrieval instructions were given in Experiment 3, same-context encoding led to greater recall of homographs from word-fragment cues relative to different-context encoding. These results are consistent with the predictions of the transfer-appropriate-processing view because little advantage for the same-context condition was obtained in implicit tests in the absence of conceptual cues. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A decrement-to-familiarity interpretation of the revelation effect from forced-choice tests of recognition memory

In the revelation effect, the probability of labeling a target or a lure as "old" on item recognition tests increases if just prior to their recognition judgment, participants first identify a disguised version of the test item. The same occurs with interpolated tasks that occur just prior to a recognition judgment if the task shares constituents with the test items. One explanation of this test bias is an increased feeling of familiarity that comes from the identification stage preceding the recognition judgment (e.g., D. C. LeCompte, 1995; C. R. Lou, 1993). This study's finding in 4 experiments that 2-alternative forced-choice recognition either yields no effects of revelation or an "antirevelation" effect, even when both items were studied or nonstudied, is incongruent with this explanation. The authors argue that revelation decrements familiarity, and this results in a more liberal criterion shift. They also argue that their theory is more consistent with previous empirical data.     

Levels of processing and selective attention effects on encoding in memory

The purpose of the present study was to investigate the effects of selective attention and levels of processing (LOPs) at study on long-term repetition priming vis-a-vis their effects on explicit recognition. In a series of three experiments we found parallel effects of LOP and attention on long-term repetition priming and recognition performance when the manipulation of these factors at encoding was blocked. When a mixed study condition was used, both factors affected explicit recognition, while their effect on repetition priming was determined by the nature of the test. Shallow processing at test did not benefit from long-term repetition, regardless of whether the words had been studied deeply or shallowly. Selective attention affected long-term repetition priming in a semantic, but not in a lexical decision (LD), test. Regardless of study condition, retention lag affected long-term repetition priming only in the semantic test. These results suggest that if the experimental conditions allow scrupulous selection of attended and unattended information or narrow tuning to a shallow, pre-lexical LOP, implicit access to unattended or shallowly studied items is significantly reduced, as is explicit recognition. We suggest a conceptual framework for understanding the effects of LOP, attention, and retention interval on performance of explicit and implicit tests of memory.     

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)     

Alcohol primes, expectancies, and the working self-concept.

Previous research has shown that alcohol consumption can lead to momentary changes in the self-concept (e.g., Steele & Josephs, 1990). In two studies (n = 150), we examined whether the implicit activation of alcohol expectancies (i.e., sociability-related expectancies) would also lead to changes in self-perception. To test this idea, participants first completed a measure of sociability-related alcohol expectancies. In a subsequent laboratory session, participants were exposed to either alcohol-related primes (i.e., pictures or words associated with alcohol) or neutral primes. After the priming task, participants completed an ostensibly unrelated self-concept survey that contained words related to sociability (e.g., “outgoing”) and nonsociability related words (e.g., “clever”). For both studies, results revealed that sociability-related alcohol expectancies were positively associated with sociability-related self-concept ratings for participants exposed to alcohol primes, but not for participants exposed to the neutral primes. Implications for the role implicit self-concept activation may have on drinking behaviors are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)