Effects of generation on indirect measures of memory.

Subjects either read words (CHIMP) or generated words ("a small ape—C') during the study phase of three experiments. The effects of these encoding tasks on performance in two indirect, priming tests—word completion and word identification—were observed. The word completion test is a version of word stem completion in which subjects are shown the initial four letters of a five-letter word (e.g., CHIM_: CHIMP, CHIME) and are asked to add one letter to produce the first word that comes to mind. In word identification, subjects are shown a word briefly and are asked to identify it. Systematic comparisons of the two tests within single experiments showed that generation, either to semantic cues or to orthographic cues, had different effects on performance in the two tests: Word identification performance was lower for words generated rather than read, whereas word completion performance for words generated was indistinguishable from performance for words read. These results suggest that performance in different indirect tests depends on the processing of different types of information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Impaired priming of new associations in amnesia.

We assessed priming of new associations in amnesic patients and healthy control subjects in a paradigm developed by P. Graf and D. L. Schacter (see record 1986-12203-001). Subjects were presented unrelated word pairs embedded in sentences (e.g., A BELL was hanging over the baby's CRADLE) and were asked to rate how well the sentences related the two words. Subjects were then given a word completion test. They were shown three-letter word stems and were asked to complete the stem with the first word that came to mind. In the same context condition, each word stem was presented together with the word that had appeared in the same sentence during study (e.g., BELL-CRA ). In the different context condition, each stem was presented together with a new word that had never been presented (e.g., APPLE-CRA ). Control subjects completed more words in the same context condition than in the different context condition. In contrast, amnesic patients did not complete any more words in the same context condition than in the different context condition. Indeed, across two experiments none of the amnesic patients exhibited consistent priming of new associations. Thus, although amnesic patients do exhibit entirely normal priming of preexisting memory representations, they do not appear to exhibit priming of new associations in this paradigm. (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.     

Typography manipulations can affect priming of word stem completion in older and younger adults.

The experiments reported here investigated whether changes of typography affected priming of word stem completion performance in older and younger adults. Across all experiments, the typeface in which a word appeared at presentation either did or did not match that of its 3-letter stem at test. In Exp 1, no significant evidence of a typography effect was found when words were presented with a sentence judgment or letter judgment task. However, subsequent experiments revealed that, in both older and younger adults, only words presented with a syllable judgment task gave rise to the typography effect (Exps 2–4). Specifically, perforance was greater when the presentation and test typeface matched than when they did not. Exp 5, which used stem-cued recall, did not reveal a difference between syllable and letter judgment tasks. These findings highlight the complex nature of word stem completion performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Guessing strategies, aging, and bias effects in perceptual identification

In the typical single-stimulus perceptual identification task, accuracy is improved by prior study of test words, a repetition priming benefit. There is also a cost, inasmuch as previously studied words are likely to be produced (incorrectly) as responses if the test word is orthographically similar but not identical to a studied word. In two-alternative forced-choice perceptual identification, a test word is flashed and followed by two alternatives, one of which is the correct response. When the two alternatives are orthographically similar, test words identical to previously studied items are identified more accurately than new words (a benefit) but tests words orthographically similar to studied words are identified less accurately than new words (a cost). Ratcliff and McKoon (in press) argue that these are bias effects that arise in the decision stage of word identification. We report five experiments that examined the alternative hypothesis that these bias effects arise from postperceptual guessing strategies. In single-stimulus perceptual identification, repetition priming benefits were equally great for young and older adults who claimed to use deliberate guessing strategies and those who did not (Experiment 1). In contrast, only groups of young and older people who claimed to deliberately guess studied words in a two-alternative forced-choice task (Experiments 2 and 5) showed reliable benefits and costs. Costs and benefits were abolished in the two-alternative forced-choice task when a very long study list was used, presumably because the increased retrieval burden made the use of deliberate guessing strategies less attractive (Experiment 3). Under conditions similar to those of Experiment 3, repetition priming was observed in single-stimulus perceptual identification (Experiment 4). These results are consistent with the view that costs and benefits in the forced-choice perceptual identification task arise from deliberate guessing strategies but that those in the single-stimulus task do not. The possibility that the observed relationship between strategy reports and priming effects reflects erroneous postexperimental assessments of strategies by participants is also considered.     

On the nature of associative information in recognition memory.

In a typical associative-recognition task, participants must distinguish between intact word pairs (both words previously studied together) and rearranged word pairs (both words previously studied but as part of different pairs). The familiarity of the individual items on this task is uninformative because all of the items were seen before, so the only way to solve the task is to rely on associative information. Prior research suggests that associative information is recall-like in nature and may therefore be an all-or-none variable. The present research reports several experiments in which some pairs were strengthened during list presentation. The resulting hit rates and false alarm rates, and an analysis of the corresponding receiver operating characteristic plots, suggest that participants rely heavily on item information when making an associative-recognition decision (to no avail) and that associative information may be best thought of as a some-or-none variable. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Form-specific priming and functional brain asymmetries in perceptual identification

Word form representations in intact cerebral hemispheres were studied by a lateralized perceptual identification priming task. During the study phase, word forms were primed by displaying words visually in uppercase or lowercase letters. During the test phase, perceptual identification of non-studied baseline words and studied words (presented in same or different lettercase as studied) was tested by displaying targets in the left or right visual field. Experiment 1 showed that the hemispheric pattern of priming effects was dependent on the lettercase at test. For uppercase test items, only the left visual field/right hemisphere was sentitive to study-test changes in lettercase, replicating an earlier result obtained in word-stem completion (Marsolek, Kosslyn and Squire, 1992). However, lowercase test items did not reveal any asymmetries in the form-dependent priming component indicating that in some conditions form-specific representations are computed in the left hemisphere also. No asymmetries were found in the abstract, form-independent component of priming. Experiment 2 revealed that use of explicit memory in the perceptual identification task eliminated the form-specific priming effects and suggested that the results of Experiment 1 were uncontaminated by explicit memory.     

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.     

Short-term implicit memory for words and nonwords.

A short-term implicit memory effect is reported and interpreted as arising within the word recognition system. In Experiment 1, repetition priming in lexical decision was determined for low-frequency words and pseudowords at lags of 0, 1, 2, 3, 4, 5, 9, and 23 intervening items. For words, a large short-term priming component decayed rapidly but smoothly over the first 3 items (8 s) to a stable long-term value. For nonwords, priming dropped to the long-term value with a single intervening item. This Lag x Lexicality interaction was replicated with a naming task in Experiment 2 and with high-frequency words in Experiment 3. Word frequency affected long-term priming but not the size or decay rate of short-term priming, dissociating the two repetition effects. In Experiment 4, an old-new decision task was used to test explicit memory. Parallel word and nonword decay patterns were found, dissociating short-term priming from explicit working memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A test of the frontal lobe functioning hypothesis of age deficits in production priming.

Older adults have been hypothesized to show reduced priming relative to younger adults on implicit memory tests that require production of a response because these tasks place high demands on attentional processes associated with frontal lobe function, which are often reduced with age (see D. A. Fleischman & J. D. E. Gabrieli, 1998). The current study directly tested this frontal lobe hypothesis of age effects in production priming. Younger adults and older adults who differed in their attentional abilities as measured by a battery of neuropsychological tests were given two production priming tasks, word stem completion and category production, followed by explicit free recall tests. Results showed that explicit memory performance was reduced by age and older adults' frontal functioning. Age and frontal functioning influenced category production priming but not word stem completion priming. Results failed to support the frontal account of age reductions in production priming. Instead, results implicate the influence of other processes often involved in production priming tasks, such as explicit memory strategies and response competition, as critical for understanding age effects in implicit memory performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Building episodic connections: Changes in episodic priming with age and dementia.

Previous studies of associative encoding that used explicit retrieval tasks have shown both age- and dementia of the Alzheimer type (DAT)-related declines, but such results may be biased by group differences in explicit retrieval. In the present experiment, the authors assessed implicit associative encoding for 25 younger adults (ages 18–25), 73 healthy older adults (ages 59–91), and 65 adults with DAT (ages 59–91) during a speeded word-naming task using an episodic priming measure. Episodic priming refers to the facilitation in responding to a target word after repetition of both words in a prime–target pair, in comparison with simple repetition of the target word with a new prime on each presentation. In contrast with other studies of implicit associative encoding that did not use an implicit episodic priming measure, the present study found both age- and DAT-related declines in associative encoding under conditions of massed learning trials. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Strategic effects in associative priming with words, homophones, and pseudohomophones.

G. Lukatela and M. T. Turvey (1994x) showed that at a 57-ms prime-presentation duration, the naming of a visually presented target word (frog) is primed not only by an associate word (toad) but also by a homophone (towed) and a pseudohomophone (tode) of the associate. At a 250-ms prime presentation, priming with the homophone was no longer observed. In Experiment 1, the authors replicated these priming effects in the Dutch language. Next, the authors extended the priming paradigm to a word/legalnon-word lexical decision task (Experiments 2 and 3) and a word/pseudohomophone decision task (Experiment 4). Phonologically mediated associative priming was observed in all conditions with pseudohomophonic primes but not with homophonic primes. The latter did not prime at a 250-ms prime-presentation time and at 57 ms in the word/pseudohomophone task. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Long-term semantic priming: A computational account and empirical evidence.

Semantic priming is traditionally viewed as an effect that rapidly decays. A new view of long-term word priming in attractor neural networks is proposed. The model predicts long-term semantic priming under certain conditions. That is, the task must engage semantic-level processing to a sufficient degree. The predictions were confirmed in computer simulations and in 3 experiments. Experiment 1 showed that when target words are each preceded by multiple semantically related primes, there is long-lag priming on a semantic decision task but not on a lexical-decision task. Experiment 2 replicated the long-term semantic priming effect for semantic decisions with only one prime per target. Experiment 3 demonstrated semantic priming with much longer word lists at lags of 0, 4, and 8 items. These are the first experiments to demonstrate a semantic priming effect spanning many intervening items and lasting much longer than a few seconds. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Facilitation of word recognition by semantic priming in schizophrenia.

Schizophrenic (n?=?21), bipolar (n?=?18), and normal control subjects (n?=?21) were compared on a word recognition measure of semantic priming. The task involved the presentation of related, neutral, and unrelated word pairs; the second word (target word) in each pair was presented in a degraded form. Facilitation was defined as the accuracy of target word recognition for the related word pairs minus accuracy for the neutral word pairs. Titration, achieved by manipulating the degradation of the target word, was used to maintain each subject's overall accuracy for related and neutral items at approximately 50%. This procedure minimized the artifactual effects of overall accuracy on the difference score. Schizophrenics exceeded both normal control subjects and bipolar subjects on facilitation. Bipolar subjects did not differ from control subjects. The results support Maher's hypothesis that semantic priming effects are heightened in schizophrenia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Priming effects in semantic classification tasks.

Six experiments were conducted on priming in semantic classification tasks that allow free play between perceptual and semantic processes. Priming was greatest when words were repeated on the same semantic task at study and test but was absent when repeated words were classified on different semantic tasks (size and man-made; Exp 1). Thus, merely repeating perceptual information is not sufficient to produce priming. Priming was obtained, however, when items on the same semantic task were repeated in different formats (words and pictures; Exp 2). Consistent with stage models of single-word reading, priming was obtained when a semantic classification task was followed by a word form task (i.e., lexical classification or naming) but not when it was preceded by the word form task (Exps 3 and 4). Priming was also found across lexical tasks that both involve the word form (Exp 5) and across classification tasks that refer to the same semantic domain (overall size and relative dimensions; Exp 6). Results suggest that priming is determined by the overlap in the component processes of the study and test tasks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

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. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The use of indirect memory tests to assess malingered amnesia: A study of metamemory.

Many techniques have been suggested for identifying criminal suspects who are simulating amnesia for events surrounding a crime. The present research focuses on indirect memory tests as a potential means of discriminating between those who genuinely suffer from amnesia and those who are simulating. Ss studied a list of words and subsequently performed either a word completion or a fragment completion task. Under normal indirect test instructions, typical priming effects were observed. When Ss were motivated to simulate amnesia for the list, target completion rates were consistently, and sometimes reliably, below baseline completion rates. This finding is contrary to the performance of genuine amnesics, whose performance on indirect tests typically mirrors that of normal Ss. Indirect tests may prove useful in discriminating genuine and simulating amnesics. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Auditory priming: Implicit and explicit memory for words and voices.

Five experiments explore priming effects on auditory identification and completion tasks as a function of semantic and nonsemantic encoding tasks and whether speaker's voice is same or different at study and test. Auditory priming was either unaffected by the study task manipulation (Exps 2, 4, and 5) or was less affected than was explicit memory (Exps 1 and 3). Study-to-test changes of speaker's voice had significant effects on priming when white noise masked target items on the identification test (Exps 1 and 2) or the stem-completion test (Exp 5). However, significant voice change effects were observed on priming of completion performance when stems were spoken clearly (Exps 3 and 4). Results are consistent with the idea that a presemantic auditory perceptual representation system plays an important role in the observed priming. Alternative explanations of the presence or absence of voice change effects under different task conditions are considered. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Word frequency effects on recall, recognition, and word fragment completion tests.

In 3 experiments, the effect of word frequency on an indirect word fragment completion test and on direct free-recall and Yes–no recognition tests was investigated. In Experiment 1, priming in word fragment completion was substantially greater for low-frequency words than for high-frequency words, but free recall was unaffected. Experiment 2 replicated the word fragment completion result and showed a corresponding effect in recognition. Experiment 3 replicated the low-frequency priming advantage in word fragment completion with the set of words that P. L. Tenpenny and E. J. Shoben (1992) had used in reporting the opposite pattern in word fragment completion. Using G. Mandler's (1980) dual-process theory, the authors argue that recognition and word fragment completion tests both rely on within-item integration that influences familiarity, whereas recall hinges on elaboration that influences retrievability. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Conceptual implicit memory performance in Alzheimer's disease.

Alzheimer's disease (AD) patients often exhibit deficits on conceptual implicit memory tests such as category exemplar generation and word association. However, these tests rely on word production abilities, which are known to be disrupted by AD. The current study assessed conceptual implicit memory performance in AD patients and elderly control participants using a conceptual priming task that did not require word production (i.e., semantic decision). Memory performance was also examined using a category exemplar generation test (i.e., a conceptual priming task that required word production) and a recognition memory test. AD patients exhibited deficits on the semantic decision task, the category exemplar generation task, and the recognition memory task. The results indicate that the conceptual memory deficits observed in AD patients cannot be attributed completely to word production difficulties. (PsycINFO Database Record (c) 2010 APA, all rights reserved)