Repetition Priming Task Research Articles

Implicit and explicit memory: a functional dissociation in persons with Down syndrome

This study aimed at investigating implicit and explicit long-term memory functioning in subjects with Down syndrome (DS) compared to Mental-Age (MA) matched normal children. For this purpose, tests of verbal and visuo-perceptual explicit memory, verbal and visual repetition priming and procedural learning tasks were administered to 14 DS and 20 MA subjects. Our results document comparable implicit memory abilities in the two groups. In contrast, regarding explicit memory, normal children performed better than DS individuals. These results reveal a functional dissociation between implicit and explicit memory in subjects with DS. Theoretical and rehabilitative implications are discussed.

Dissociation between two forms of conceptual priming in Alzheimer's disease.

Patients with Alzheimer's disease (AD) and healthy control participants performed 2 conceptual repetition priming tasks, word-associate production and category-exemplar production. Both tasks had identical study-phases of reading target words aloud, had the most common responses as target items, and required production of a single response. Patients with AD showed normal priming on word-associate production but impaired priming on category-exemplar production. This dissociation in AD suggests that conceptual priming is not a unitary form of memory but rather is mediated by separable memory systems.

Repetition priming in normal aging and Alzheimer's disease: a review of findings and theories.

On repetition priming tasks, memory is measured indirectly as a change in performance due to recent experience. It is often functionally and neurally dissociated from performance on explicit memory tasks, which directly measure conscious recall or recognition of recent events. Repetition priming has therefore been extensively studied in normal aging and Alzheimer's disease, which feature mild to severe changes in explicit memory. Initial studies indicated that repetition priming was immune to the effects of aging and greatly reduced in Alzheimer's disease (AD). As more studies have been performed, however, these initial conclusions appear less clear than before and, in the case of AD, actually misleading. The purpose of this article is to provide a comprehensive review of this rapidly expanding literature, articulate the issues that are critical to interpreting the empirical results, and discuss what new conclusions are suggested by the overall pattern of findings.

Universals in Morphological Representation: Evidence from Italian

The dual mechanism hypothesis argues that the apparent contrast, in English inflectional morphology, between a rule-based default procedure, generating regular past-tense forms, and listed irregular forms stored in an associative net, reflects universal constraints on the properties of possible morphological systems. This research asked whether these constraints can be shown to hold, in the ways predicted by the dual mechanism hypothesis, for Italian past-tense inflection. Experiment 1, using a cross-modal repetition priming task, showed that priming generated by regular inflected pairs (giocarono/giocare) does not differ from prim ing by irregular inflected pairs (scesero/scendere). Experiment 2, using an elicitation task where subjects produce past-tense forms for novel verbs, not only showed little evidence for the presence of an underlying default, but also demonstrated that phonological similarity can affect both regularised and irregularised elicitation patterns. The results of both experiments contrast with previous research in English, which used the same techniques, and suggest that claims about universal morphological patterns

Long-term memory in mental retardation: Evidence for a specific impairment in subjects with Down's syndrome

This study aimed at investigating long-term memory functioning in Down's syndrome subjects (DS) as compared to individuals with mental retardation of different etiology (MR) and mental-age matched normal children (MA). For this purpose, tests of verbal and visuo-perceptual explicit memory and a verbal repetition priming task were administered to 15 DS, 15 MR and 30 MA subjects. Our results document comparable verbal priming in the three groups. As for explicit memory, normal children performed better than MR individuals, and these, in turn, better than DS subjects. Compared to MR subjects, DS subjects were particularly deficient in organizing verbal material according to its categorical structure and in actively retrieving stored information. These results support a view positing heterogeneity of neuropsychological deficits across distinct etiology MR groups.

Perceptual and conceptual components in implicit and explicit stem completion

This study was aimed at investigating functional and neuropsychological dissociations between repetition priming and explicit memory tasks. The explicit and implicit versions of the stem completion task were administered to a group of amnesics and a group of control subjects. In Experiment 1 both the explicit and implicit stem completions were significantly higher when the same presentation modality was used for studying and testing than when a change in modality from studying to testing occurred. Amnesics had normal implicit and deficient explicit completion performance. Experiment 2 revealed an advantage of the semantic over the phonological condition only in the explicit task and only in control subjects. Amnesic patients completed the same percentage of words as normal subjects in the phonological and semantic conditions of the implicit task and in the phonological condition of the explicit task but were deficient in intentionally completing semantically processed words. Possible interpretations of these results are discussed according to theoretical models that distinguish memory tasks along an explicit-implicit dichotomy (multiple memory system theory) or along a perceptual-conceptual dichotomy (transfer-appropriate procedures approach), and alternative theoretical positions are evaluated regarding repetition priming and memory deficits in amnesic patients.

Implicit memory and aging: A cognitive neuropsychological perspective

Although it is well‐established that there are age deficits on measures of explicit memory, there is conflicting evidence as to whether implicit memory, as measured by performance on various repetition priming tasks, is impaired by age. In order to clarify the relation between aging and implicit memory, priming tasks were organized in the following categories: (a) perceptual‐item priming, (b) perceptual‐associative priming, (c) conceptual‐item priming, (d) conceptual‐associative priming, and (e) perceptual‐motor priming. The taxonomy took into account the type of mental representation that different priming tasks depend on, the neurological structures responsible for these representations, the extent to which priming tasks demand the formation of novel associations, and the various blends of data‐driven and conceptually driven processes that facilitate task performance. A literature review based on this taxonomy revealed two tentative conclusions. First, the processes associated with normal aging are like...

Stem-completion priming in Alzheimer's disease: The importance of target word articulation

Stem-completion priming performance in patients with Alzheimer's type dementia (DAT) was explored in three experiments in which both the standard repetition priming effect and a novel indirect form of priming, cohort priming, were measured. In the first experiment, in which study stimuli were words, both priming effects were found to be markedly attenuated in the DAT group. In the second experiment, the study stimuli were specially constructed nonwords, and it was found that cohort priming was present at normal levels in the DAT group. In a third experiment we tested the specific hypothesis that the requirement to overtly articulate target stimuli during the study phase was critical for the appearance of normal cohort priming in the DAT group in Experiment 2, and also for the normal levels of repetition priming which have been reported in some published studies. Two encoding conditions were compared, one in which subjects simply had to read aloud the target words and a second in which subjects were required to make evaluative (pleasantness) ratings for each of the target words (identical to that used in Experiment 1). Stem-completion priming performance following the latter condition was significantly attenuated in the DAT group relative to a healthy control group, but following the “read aloud” encoding condition, normal levels of repetition and cohort priming were observed. It is suggested that the most fruitful approach to understanding the performance of DAT subjects on lexical repetition priming tasks will involve a detailed analysis of language functions and how they interact with other, possibly mnemonic, processes in the generation of primed responses.

Phonological variation in lexical access: Abstractness, inference and english place assimilation

Abstract Phonological variation in the phonetic form of words is a challenge to theories of lexical access and speech perception. This paper reviews some recent research on English place assimilation (e.g. sweet articulated as sweep in the environment sweet boy), evaluating an account of variation in terms of abstract, underspecified lexical form representations. An initial gating study confirms that potentially assimilated forms (surface velar or labial stops) are perceptually more ambiguous than coronal stops, which cannot be derived through assimilation from a following consonant. A second set of studies, using repetition-priming tasks with isolated words, finds little direct evidence to support a pure representational hypothesis, where place assimilated features are mapped onto underspecified representations at the lexical level. A final set of studies, looking at assimilated tokens in sentence contexts, finds evidence both for a representational account and for a determining role played by processes of phonological inference, operating over the phonological context in which variation occurs. This leads to a hybrid account where abstract lexical representations can be contacted directly by varying phonetic forms, but where further interpretation requires on-line processes of context-sensitive inference.

Perceptual and conceptual priming in amnesic and alcoholic patients

This study investigated the contribution of perceptual and conceptual processes to the repetition priming effect, and evaluated alternative theoretical positions about repetition priming in amnesic patients. Toward this end, we administered three repetition priming tasks (Stem Completion, Word Identification and Free Association) and an explicit memory task (yes/no Recognition) to amnesic and alcoholic patients, and tested the sensitivity of these tasks to level of processing and to manipulations of presentation modality. Experiment 1 demonstrated that the level of priming in Stem Completion and Free Association (but not in Word Identification) was enhanced by semantic elaboration of the stimuli. Experiment 2 revealed that the magnitude of priming in Word Identification and Stem Completion (but not in Free Association) was larger in the intramodal then in the intermodal condition. Amnesic patients displayed normal perceptual as well conceptual priming. Possible interpretations of these results according to theoretical models that distinguish memory tasks along an explicit-implicit dichotomy ( multiple memory system theory), or on the basis of the extent to which they depend upon perceptual or conceptual processing ( transfer-appropriate procedures approach), or that assumes a possible contamination of priming performance by explicit strategies of retrieval are discussed.

Beyond Orthography and Phonology: Differences between Inflections and Derivations

The influence of morphological structure was investigated in two types of word recognition tasks with Serbian materials. Morphological structure included both inflectional and derivational formations and comparisons were controlled for word class and the orthographic and phonological similarity of forms. In Experiments 1, 2, and 3, the pattern of facilitation to target decision latencies was examined following morphologically-related primes in a repetition priming task. Although all morphologically related primes facilitated targets relative to an unprimed condition, inflectionally related primes produced significantly greater effects than did derivationally related primes. In Experiments 4, 5, and 6 subjects were required to segment and shift an underlined portion from one word onto a second word and to name the result aloud. The shifted letter sequence was sometimes morphemic (e.g., the equivalent of ER in DRUMMER) and sometimes not (e.g., the equivalent of ER in SUMMER). Morphemic letter sequences were segmented and shifted more rapidly than their nonmorphemic controls when they were inflectional affixes but not when they were derivational affixes. These results indicate that (a) morphological effects cannot be ascribed to orthographic and phonological structure, (b) the constituent morphemic structure of a word contributes to word recognition and (c) morphemic structure is more transparent for inflectional than for derivational formations.

Priming in perceptual identification of pseudowords is normal in Alzheimer's disease

Patients with Alzheimer's disease (AD) have deficits in recall and recognition memory, and show dissociable performance in repetition priming tasks: They exhibit impaired priming in word-completion and word-generation tasks, but normal priming in perceptual identification of words. In order to examine whether AD patients can show normal priming with novel, unfamiliar stimuli, the present study examined their performance in perceptual identification of pseudowords. Despite impaired recognition memory performance, AD patients showed normal priming in perceptual identification of pseudowords. These results extend the boundaries of intact repetition priming in AD, demonstrating that such priming is not limited to stimuli that are pre-morbidly represented in long-term knowledge. Preserved repetition priming in AD may reflect the operation of perceptual processes localized to posterior visual circuits that are relatively spared in AD.

Morphology and meaning in the English mental lexicon.

The authors investigated the lexical entry for morphologically complex words in English. Six experiments, using a cross-modal repetition priming task, asked whether the lexical entry for derivationally suffixed and prefixed words is morphologically structured and how this relates to the semantic and phonological transparency of the surface relationship between stem and affix. There was clear evidence for morphological decomposition of semantically transparent forms. This was independent of phonological transparency, suggesting that morphemic representations are phonologically abstract. Semantically opaque forms, in contrast, behave like monomorphemic words. Overall, suffixed and prefixed derived words and their stems prime each other through shared morphemes in the lexical entry, except for pairs of suffixed forms, which show a cohort-based interference effect

The contribution of morphology to word recognition

Evidence of morphological processing was investigated in three word recognition tasks. In the first study, phonological ambiguity of the base morpheme in morphologically complex words of Serbo-Croatian was exploited in order to evaluate the claim that the base morpheme serves as the unit by which entries in the lexicon are accessed. An interaction of base morpheme ambiguity and affix characteristics was obtained and this outcome was interpreted as evidence that all morphological constituents of a word participate in lexical access. In the second study, facilitation due to morphological relatedness of prime and target was observed with Serbo-Croatian materials in the lexical decision and naming versions of the repetition priming task and results were interpreted as evidence of a morphological principle of organization among whole-word forms in the lexicon. In the third study, morphological affixes of both English and Serbo-Croatian words were segmented from a source word and affixed to a target word more rapidly than phonemically matched controls. Results suggest that the morphological constituents of complex words are available in some word recognition tasks and that morphological knowledge is represented in the speaker's lexicon.

Decay of repetition priming effects and its relation to retention from text processing: A study of forgetting

An experiment tested hypothesized relationships between memory strength and decay parameters estimated from a repetition priming task and retention from text processing. A sample of 295 Air Force enlisted personnel performed computer administered cognitive tasks to measure (a) verbal knowledge, (b) working memory efficiency, (c) retention from previous text processing, and (d) repetition savings and decay. Repetition savings and decay parameters were estimated from facilitation on repeated semantic comparison trials ( moist = damp?) over variable lag intervals. Retention from text processing was estimated by readministering questions but not text passages from an Air Force reading test that subjects had taken one week earlier (original test scores were used to statistically control for comprehension differences). General verbal knowledge and working memory measures predicted original comprehension, but not retention. Only repetition savings and decay parameters predicted retention. These results argue against previous conclusions that there are no individual differences in forgetting independent of acquisition differences. In addition, results from this and previous work suggest that individual differences in certain forms of knowledge acquisition and retention may be partly a function of differences in memory strengthening and decay processes evident from single processing episodes.

Repetition of semantic comparisons: Temporary and persistent priming effects.

Abstract : Two experiments tested the involvement of both abstract semantic memory representations and instance specific memory for feature encoding in repetition effects for a semantic processing task. Experiment 1 showed that a relatively small amount of facilitation (10%-15%) was attributable to memory for instance specific features (typography) of repeated trials. Although small, this effect showed no decay over repetition lags investigated, suggesting persistent memory for encoded features or encoding processes. Experiment 2 showed that facilitation for semantically related repetitions was short-lived compared with facilitation for lexically exact repetitions. This suggested that priming of abstract semantic memory may be involved in temporary but not persistent repetition effects. Individual differences analyses supported the conclusion that despite the increased semantic complexity of this repetition priming task over those previously used, abstract semantic memory representations were not involved in persistent repetition effects.

Formal relationships among words and the organization of the mental lexicon.

A series of experiments investigated the role of orthography in the organization of the mental lexicon. A pilot experiment had found no effect of formal overlap between words on a repetition priming task at a lag of 56 intervening items. The first two experiments reported here used a lag of zero and varied SOA. Formal priming was found at SOAs of 1,650 milliseconds and less. However, reducing the proportion of related primes and targets in the experiment reduced formal priming. Moreover, it did so not by affecting response times to formally related primes and targets but by reducing response times to comparison trials in which primes and targets were unrelated. This led to a hypothesis that the formal priming we had observed was only apparent and due to strategic inhibition of responses to unrelated prime-target pairs. The final experiment reduced the proportion of responses to related targets further and examined formal priming at lags of 0, 1, 3, and 10. No formal priming was found under these conditions. Across all experiments, where formal priming occurred, it was due to changes in levels of inhibitory priming in comparison conditions. The conclusion is drawn that convincing evidence for an orthographic or phonological organization of the lexicon is not obtainable using priming procedures.