Priming In Word Identification Research Articles

Repetition priming without identification of the primes: Evidence for a component process view of priming

The aim of the present study was to examine whether priming can occur due to recent perceptual processing of the same stimulus with minimal influence from conceptual process and also to investigate its underlying neural mechanisms using fMRI. Words were presented in mirror orientation in a word identification priming task. The presentation durations of the primes were titrated individually so that each participant could only identify approximately half of the primes, while the remainder disappeared before participants could identify the meaning of the word. A substantial behavioral priming effect was found when these unidentified primes were repeated later, suggesting that recent exposure to the perceptual processes without accessing the meaning is sufficient to prime later identical processes of the same repeated stimuli. Imaging data showed significant repetition suppression in several brain regions mediating perceptual, but not semantic or conceptual, processes. Together, our findings are consistent with the general predictions of transfer appropriate processing (TAP) and the component process view of priming, positing that priming is a function of more efficient cognitive processes that are repeated from study to test, and this increased efficiency is reflected in repetition suppression effects evident on fMRI.

Implicit memory and Alzheimer's disease neuropathology

Explicit memory failure is the defining cognitive feature of Alzheimer's disease and relates to the hallmark neuropathological features (plaques and tangles) of this illness. However, a pattern of preserved and impaired implicit memory has been found in Alzheimer's disease patients that may be explained by the association between the processing demands of certain implicit tests and the level of regional Alzheimer's disease neuropathology. In this study, we tested the hypothesis that these neuropathological features are related to implicit memory--measured by repetition priming--in a test that emphasized conceptual (or meaning-based) cognitive processing, and that the pathological changes are not related to implicit memory in a repetition priming test that emphasized perceptual (or sensory-based) cognitive processing. Subjects were older nuns, priests and brothers participating in the Religious Orders Study who agreed to annual neurological and neuropsychological evaluation for Alzheimer's disease and common neurological conditions of ageing, and brain autopsy at time of death. Explicit memory was measured by seven tests of episodic recall and recognition and converted to a previously established summary measure. Implicit memory was measured by four repetition priming tests. One test, category exemplar priming, emphasized conceptual, or meaning-based cognitive processing. A second test, word-identification priming, emphasized perceptual, or sensory-based cognitive processing. Two additional priming tests, picture-naming and word-stem completion, invoke both conceptual and perceptual processes. Neuritic and diffuse plaques, and neurofibrillary tangles identified by Bielschowsky silver stain, were quantified from five regions separately (frontal, parietal, temporal, entorhinal cortex and the hippocampus) and converted to a previously established summary measure. In linear regression analyses--controlling for age, sex and education--higher levels of Alzheimer's disease neuropathology were related to lower levels of explicit memory proximate to death. Higher levels of neuropathology were also related to lower levels of priming on the category-exemplar test, but were not related to levels of priming on the word-identification, picture-naming, or word-stem completion tests. The results suggest that hallmark indices of Alzheimer's disease neuropathology are associated with performance on priming tests to the extent that conceptual, but not perceptual, processing resources are required.

Covert operations: Orthographic recoding as a basis for repetition priming in word identification.

When a word is generated from a semantic cue, coincident orthographic visualization of that word may cause priming on a subsequent perceptual identification test. A task was introduced that required subjects to visualize the orthographic pattern of auditorily presented words. When used at study, this task produced a pattern of priming similar to that produced by a generate study task. When used at test, equal priming on the orthographic task was produced by read and generate study tasks but not by a generate study task that failed to invite orthographic visualization. Priming on perceptually based word identification tests that results from a generate study episode may be largely due to orthographic recoding of the target rather than to conceptual processing.

A multinomial model for short-term priming in word identification.

A simple multinomial model for short-term priming in perceptual word identification is presented. In the experiments to which the model is applied, prime words are presented just prior to a flashed target word, and subjects must decide which of 2 alternative words matches the target. The model assumes that on some proportion of trials, confusion among the words leads to the decision being based on 1 of the prime words instead of the target. In addition, it is assumed that subjects sometimes discount a prime that matches 1 of the test alternatives and so choose the alternative that does not match. With these assumptions, the model fits the data from 5 experiments (including 4 used to develop the model known as ROUSE [responding optimally with unknown sources of evidence]; D. E. Huber, R. Shiffrin, K. Lyle, & K. Ruys, 2001). The multinomial model fits the data about as well as the ROUSE model and so should lead to further development and critical testing of both models.

A multinomial model for short-term priming in word identification.

A multinomial model for short-term priming in word identification.

Word-Identification Priming for Ignored and Attended Words

Three experiments examined contributions of study phase awareness of word identity to subsequent word-identification priming by manipulating visual attention to words at study. In Experiment 1, word-identification priming was reduced for ignored relative to attended words, even though ignored words were identified sufficiently to produce negative priming in the study phase. Word-identification priming was also reduced after color naming relative to emotional valence rating (Experiment 2) or word reading (Experiment 3), even though an effect of emotional valence upon color naming (Experiment 2) indicated that words were identified at study. Thus, word-identification priming was reduced even when word identification occurred at study. Word-identification priming may depend on awareness of word identity at the time of study.

A Dissociation between Perceptual Explicit and Implicit Memory Processes

Patient M.S., who underwent right-occipital lobe resection to treat intractable epilepsy, has intact recall and recognition memory for words, but impaired repetition priming in word identification and visual stem-completion tasks. This mirror dissociation to amnesia suggests that explicit recognition and visuoperceptual repetition priming are mediated by distinct neural systems. In prior studies, however, M.S.' recognition memory was tested only with tasks that drew upon his intact verbal knowledge. The present study examined M.S.' recognition memory for nonverbal perceptual information, namely, the modality and font of word presentation and line patterns. M.S.' recognition memory was intact, providing further evidence that perceptual explicit and implicit memory processes are subserved by functionally and neurally independent memory systems.

Dissociations between familiarity processes in explicit recognition and implicit perceptual memory.

Dual-process theories of recognition posit that a perceptual familiarity process contributes to both explicit recognition and implicit perceptual memory. This putative single familiarity process has been indexed by inclusion-exclusion, remember-know, and repetition priming measures. The present studies examined whether these measures identify a common familiarity process. Familiarity-based explicit recognition (as indexed by the inclusion-exclusion and the independence remember-know procedures) increased with conceptual processing. In contrast, implicit word-identification priming and familiarity-based word-stem completion (as indexed by inclusion-exclusion) increased with study-test perceptual similarity. These dissociations indicate that familiarity-based explicit recognition may be more sensitive to conceptual than to perceptual processing and is functionally distinct from the perceptual familiarity process mediating implicit perceptual memory.

Implicit Verbal Memory in Alzheimer's Disease

Word stem completion and word identification were used in two repetition priming experiments to evaluate the implicit memory performance of Alzheimer's disease (AD) patients. This issue was also approached using various meta-analyses combining and contrasting previously reported data.While the experimental results suggested that AD patients present preserved repetition priming in both tasks, the meta-analytic approach showed an impairment in stem completion in comparison to word identification. Converging evidence cautiously suggested to accept the results of the meta-analysis. The above dissociation has been interpreted as showing differences in the specific contribution of data- and conceptually-driven processes in the two implicit tasks. A further meta-analysis on the effect of reduced perceptual availability of the study material on the same two tasks indicated that this variable affected repetition priming in word identification more heavily than in stem completion. The impact of such a dissociation on theories of implicit memory is discussed.

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.

Associative priming in perceptual identification: Effects of prime-processing requirements

Three experiments assessed the effects of prime-processing instructions on associative priming in word identification and episodic memory for primes. In Experiment 1, groups instructed to read the prime silently or generate silently an associate of the prime showed a larger accuracy benefit for related over unrelated targets than did a group that decided whether an asterisk was to the right or left of the prime. The asterisk-search group showed a weaker repetition effect on a subsequent identification test of primes, indicating that the weaker priming in this group was a result of poorer perceptual processing. On a cued-recall test for primes, the generate group was superior to the other groups. In Experiment 2, we found that with weak prime-target associations, priming was comparable for read and generate groups and stronger than estimated for a guessing strategy, on the basis of single predictions made from each prime by an additional group. In Experiment 3, we demonstrated that the read and generate instructions produced similar mispriming and inhibitory effects. The results suggest that the depths of prime-processing manipulations do not have parallel effects on priming and episodic memory, and that associative priming in word identification, as in other tasks, may involve an expectancy process.

Does organization improve priming?

In five experiments, the effects of organization on implicit memory or priming tests were compared with its effects on the explicit memory tests of free and cued recall. Organization was manipulated by varying list structure (blocked vs. random presentation of categorized items) and by instructions. The results showed that organization had parallel effects on the category-production priming test and free- and cued-recall tests; performance was enhanced by organization on both types of tests. It was also demonstrated that the effect of organization on priming was limited to the category-production test and was not obtained with the word-identification priming test. These results suggest that performance on implicit and explicit memory tests is similarly affected by experimental manipulations when both types of tests rely on conceptually driven processing. In addition, performance on two implicit tests is dissociated when one test relies on conceptually driven processing and the other on data-driven processing.