Category Exemplar Generation Research Articles

Age and processing effects on perceptual and conceptual priming.

Explicit (declarative) memory declines with age, but age effects on implicit (nondeclarative) memory are debated. Some studies have reported null changes in implicit memory (e.g., priming in word-fragment completion, perceptual identification, category exemplar generation) with age, while others have uncovered declines. One factor that may account for these discrepancies is processing. Evidence suggests that conceptual and perceptual processes are not equally affected by ageing, yet processing requirements have varied greatly between studies. Processing may moderate age effects on priming, but no study has systematically examined this issue. This registered report presents an experiment to manipulate processing (conceptual / perceptual) during incidental encoding of words, prior to measures of perceptual (perceptual identification) and conceptual (category verification) priming. The perceptual and conceptual priming tasks were matched on all characteristics except processing, making them highly comparable. The four orthogonal conditions (perceptual encoding, perceptual test [PP]; conceptual encoding, perceptual test [CP]; perceptual encoding, conceptual test [PC]; conceptual encoding, conceptual test [CC]) were designed to clarify situations in which age effects on implicit memory emerge, which holds important practical and theoretical implications. Significant effects of Age, Test, and an Age × Processing interaction emerged. Priming was greater in young than older adults and on the perceptual than the conceptual test, but in contrast to the predictions, the age difference was only significant when prior encoding was perceptual (i.e., in the PP and CP conditions).

Explicit and implicit conceptual memory in pregnancy and postpartum: A cross-sectional study investigating the use of item-specific and relational encoding processes.

Previous studies indicate that pregnancy is associated with a mild impairment in verbal recall tasks, but the relative roles of item-specific and relational encoding processes have not been fully elucidated. The present study was specifically aimed at determining whether pregnancy had a differential impact on the use of these 2 types of encoding processes. The performance of pregnant, postpartum, and control women was assessed in the category-cued recall (Experiment 1: explicit memory) and category exemplar generation (Experiment 2: implicit memory) tasks, by simultaneously varying the number of exemplars presented during the study phase (1 exemplar for small categories, 6 exemplars for large categories). Control women showed the expected crossed double dissociation: Performance in category-cued recall was better for small than for large categories (confirming that this task relied on the use of item-specific encoding processes), whereas repetition priming in category exemplar generation was higher for large than for small categories (confirming that this task relied on the use of relational encoding processes). For pregnant and postpartum women, no significant differences between small and large categories were detected in the category-cued recall task; furthermore, in the category exemplar generation task, these 2 groups exhibited greater priming for small category exemplars. Overall, our data suggest that pregnancy might involve complex changes in the use of item-specific and relational encoding processes. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

O5.3. IMPAIRED LEFT TEMPORAL-PARIETAL JUNCTION FMRI ACTIVITY DURING CATEGORY FLUENCY IN FIRST-EPISODE PSYCHOSIS

BackgroundLanguage impairments are a core feature of schizophrenia. Category fluency is severely impacted, even as early as the first-episode of psychosis (FEP). It remains unclear which brain regions in the early course of schizophrenia are dysfunctional during category fluency. Therefore, we investigated differences in fMRI bold activity during a category fluency task in FEP, with particular attention to left temporo-parietal junction (TPJ) and inferior frontal gyrus (IFG), areas critical to verbal fluency. Our hypothesis was that left TPJ would show overactivity in FEP due to functional dysconnectivity with IFG, thought to modulate TPJ activation.MethodsTwenty-seven FEP and 25 matched healthy controls (HC) completed an overt category fluency task (animal naming) from the MATRICS Consensus Cognitive Battery (MCCB), and a covert category fluency task while BOLD fMRI was acquired. The fMRI task had a total of 10 blocks (30s duration) with two alternating conditions: category and rest. At the beginning of the category condition, a category name (birds, breeds of dogs, fruits and vegetables, fish, flowers and trees) was displayed on the screen, and individuals were instructed to think of items within that category. At the beginning of the rest condition, individuals were instructed to silently repeat the word “rest” to themselves. To isolate the activity related to category exemplar generation, the rest condition and the category condition fMRI data were contrasted using SPM12. An uncorrected cluster-defining primary threshold of p<.001 was used at the voxel level, and an FWE correction was used at the cluster level to correct for multiple comparison.ResultsFEP (47.3±12.1) were significantly less fluent compared to HC (55.8±11.3) in the overt MCCB category fluency task (p =.017). In the fMRI covert fluency task, several regions were activated during the category condition (FWE p<.05), primarily including regions in the language network (IFG and TPJ). The left TPJ activation interacted between groups (pFWE-corr =.016). During the category task, HC deactivated left TPJ, whereas FEP did not.DiscussionFEP have impaired overt category fluency performance, and appear to have deficient deactivation in a region of the left TPJ language area during a category fluency task. TPJ is thought to communicate with Wernicke’s area to translate thoughts into words. Temporal language areas are also thought to be deactivated by IFG during verbal fluency tasks. This fMRI finding is consistent with dysconnectivity between IFG and TPJ during verbal fluency, although future work is needed to definitively address this possible network dysfunction.

Replication and extension of long-term implicit memory: Perceptual priming but conceptual cessation.

We endeavored to replicate Mitchell's (2006) finding of 17-year implicit memory priming. Subjects saw word and picture stimuli in 1999-2000 (M age = 18.9) and were retested after 11-14 years (M = 13.2; M age = 32.1). Via the internet, they completed four implicit memory tasks: picture fragment identification, word fragment completion, word stem completion, and category exemplar generation. Relative to control subjects (matched on stimuli, age, and education), longitudinal subjects revealed priming on picture and word fragment identification (perceptual tasks), but no priming on word stem completion or category exemplar generation (conceptual tasks). Four longitudinal subjects who failed to recall participating in the prior laboratory session had priming similar to the 10 subjects who did remember. Thus, we replicated the longevity of perceptual priming for pictures, and extended this to word fragment priming as well.

Effects of Saccade Induced Retrieval Enhancement on conceptual and perceptual tests of explicit & implicit memory

The effects of saccadic horizontal (bilateral) eye movements upon tests of both conceptual and perceptual forms of explicit and implicit memory were investigated. Participants studied a list of words and were then assigned to one of four test conditions: conceptual explicit, conceptual implicit, perceptual explicit, or perceptual implicit. Conceptual tests comprised category labels with either explicit instructions to recall corresponding examples from the study phase (category-cued recall), or implicit instructions to generate any corresponding examples that spontaneously came to mind (category-exemplar generation). Perceptual tests comprised of word-fragments with either explicit instructions to complete these with study items (word-fragment-cued recall), or implicit instructions to complete each fragment with the first word that simply ‘popped to mind’ (word-fragment completion). Just prior to retrieval, participants were required to engage in 30 s of bilateral vs. no eye movements. Results revealed that saccadic horizontal eye movements enhanced performance in only the conceptual explicit condition, indicating that Saccade-Induced Retrieval Enhancement is a joint function of conceptual and explicit retrieval mechanisms. Findings are discussed from both a cognitive and neuropsychological perspective, in terms of their potential functional and neural underpinnings.

The Facilitating Role of Task Alternation on Group Idea Generation

During group idea generation, group members often first retrieve typical ideas from common categories. The sharing of these typical ideas is likely to lead to fixation on them preventing subsequent creative idea generation. Two experiments were conducted to examine whether a task-alternation approach can reduce such fixation and facilitate idea generation. Dyads were asked to work on idea generation tasks (Experiment 1) or category–exemplar generation tasks (Experiment 2). In both experiments, dyads had to perform the tasks in either a continuous or an alternating condition. The continuous dyads worked on one task continuously before proceeding to another. The alternating dyads switched between tasks. Both experiments found a positive role of task alternation. Moreover, the performance gap between the alternating and continuous dyads increased over time. We conclude that task alternation facilitates group idea generation, most likely via overcoming fixation.

Effects of Divided Attention at Retrieval on Conceptual Implicit Memory.

This study investigated whether conceptual implicit memory is sensitive to process-specific interference at the time of retrieval. Participants performed the implicit memory test of category exemplar generation (CEG; Experiments 1 and 3), or the matched explicit memory test of category-cued recall (Experiment 2), both of which are conceptually driven memory tasks, under one of two divided attention (DA) conditions in which participants simultaneously performed a distracting task. The distracting task was either syllable judgments (dissimilar processes), or semantic judgments (similar processes) on unrelated words. Compared to full attention (FA) in which no distracting task was performed, DA had no effect on CEG priming overall, but reduced category-cued recall similarly regardless of distractor task. Analyses of distractor task performance also revealed differences between implicit and explicit memory retrieval. The evidence suggests that, whereas explicit memory retrieval requires attentional resources and is disrupted by semantic and phonological distracting tasks, conceptual implicit memory is automatic and unaffected even when distractor and memory tasks involve similar processes.

Dissociation between Conceptual and Perceptual Implicit Memory: Evidence from Patients with Frontal and Occipital Lobe Lesions.

The latest neuroimaging studies about implicit memory (IM) have revealed that different IM types may be processed by different parts of the brain. However, studies have rarely examined what subtypes of IM processes are affected in patients with various brain injuries. Twenty patients with frontal lobe injury, 25 patients with occipital lobe injury, and 29 healthy controls (HC) were recruited for the study. Two subtypes of IM were investigated by using structurally parallel perceptual (picture identification task) and conceptual (category exemplar generation task) IM tests in the three groups, as well as explicit memory (EM) tests. The results indicated that the priming of conceptual IM and EM tasks in patients with frontal lobe injury was poorer than that observed in HC, while perceptual IM was identical between the two groups. By contrast, the priming of perceptual IM in patients with occipital lobe injury was poorer than that in HC, whereas the priming of conceptual IM and EM was similar to that in HC. This double dissociation between perceptual and conceptual IM across the brain areas implies that occipital lobes may participate in perceptual IM, while frontal lobes may be involved in processing conceptual memory.

Collaboration in implicit memory: evidence from word-fragment completion and category exemplar generation.

Recent studies have begun to investigate the effects of collaboration on explicit tests such as free recall, cued recall, and recognition. In contrast, little is known about the impact of this variable on implicit memory. To bridge this gap, the present study compared the performance of nominal and collaborative groups in two implicit memory tasks-word-fragment completion (WFCT) and category exemplar generation (CEGT). Both the disruption-of-individual-retrieval-strategies and the retrieval blocking hypotheses predicted no significant negative effects of collaboration on repetition priming; in contrast, the retrieval inhibition hypothesis predicted lower priming in collaborative than in nominal groups in both tasks. The results supported the former hypotheses, because priming scores in the WFCT and the CEGT did not differ between collaborative and individual groups. Interestingly; however, a significant collaborative inhibition was obtained in the CEGT (but not in the WFCT) when considering the raw proportions of studied and unstudied exemplars generated. The latter finding might indicate that the performance of collaborative groups can be significantly impaired by the disruption of within-category order resulting from the exposure to the exemplars generated by other group members, even when participants do not explicitly attempt to retrieve the stimuli presented at encoding.

Explicit Memory and Implicit Memory in Occipital Lobe Stroke Patients

Occipital stroke patients mainly showed cortical blindness and unilateral vision loss; memory is generally reserved. Recent reports from neuroimaging show the occipital lobe may be involved in the processing of implicit memory (IM), especially the perception type of IM processing. In this study, we explored the explicit memory (EM) and IM damage in occipital lobe stroke patients. A total of 25 occipital strokes and 29 years of age, educational level equivalent healthy controls (HCs), evaluated by using immediate recall, delayed recall, recognition for EM tasks, picture identification, and category exemplar generation for IM tasks. There was no significant difference between occipital stroke patients and HCs in EM tasks and category exemplar generation task. In the picture identification task, occipital lobe stroke group score was poorer than HC group, the results were statistically significant, but in the pictures identify rate, occipital stroke patients and normal control group had no significant difference. The occipital stroke patients may have IM damage, primarily damage the perception type of IM priming effects, which was unrelated with their cortical blindness.

Is conceptual implicit memory impaired in schizophrenia? Evidence from lexical decision and category verification

Introduction. Implicit memory tasks differ along two orthogonal dimensions, tapping the relative involvement of perceptual/conceptual and identification/production processes. Previous studies have documented a dissociation between perceptual (spared) and conceptual (impaired) implicit memory, using in the latter case a production task (category exemplar generation), in which there is high response competition during the retrieval phase. The present study sought to determine whether the perceptual/conceptual dissociation held when comparing two identification tasks, in which there is no response competition at retrieval.Methods. In two experiments, repetition priming was assessed in 44 schizophrenic patients and 46 healthy controls in lexical decision (a test based on perceptual identification processes) and category verification (a test based on conceptual identification processes).Results. Schizophrenic patients achieved a priming as high as that of controls in the lexical decision task. In contrast, only controls exhibited significant priming in the category verification task.Conclusions. It is concluded that schizophrenia is associated with a specific deficit in conceptual implicit memory, irrespective of the degree of response competition in the test phase.

Category exemplars normed in Canada.

Normative data on category exemplar generation are widely used by psychologists but vary across cultures such that well-known norm sets developed in the United States might not be appropriate for use in Canada. To date, no published set of category exemplars has been normed with a Canadian undergraduate population. We describe the creation of such a set using the popular Battig and Montague (1969) categories and provide a link to the full set of norms.

Changes of Procedural Memory in the Patients with Primary Insomnia

Objective: To explore changes of procedural memory in the patients with primary insomnia (PI) and its characteristics. Methods: Thirty-six PI patients and 36 controls were enrolled. The procedural memory was respectively detected by category exemplar generation and motor sequence tasks respectively, and the declarative memory was assessed by free word task. Results: Compared to the controls, the PI patients showed few correct numbers in the category exemplar generation (7.7 ± 2.1 vs. 9.9 ± 1.0, z = 5.247, P<0.001), motion sequence task (8.1 ± 3.3 vs 12.0 ± 3.0, z = 4.676, P<0.001) and the phases of immediate recall (3.3 ± 1.1 vs 6.0 ± 1.2, z=6.634, P<0.001), delayed recall (9.0 ± 2.2 vs. 11.2 ± 1.1, z=4.718, P<0.001) and delayed recognition (14.2 ± 1.0 vs. 15.0 ±0.0, z = 4.637, P<0.001) of the free word task. For the different subtypes of PI, the early morning awakening group had significantly worse performance in the motor sequence task compared to the difficulty initiating sleep (z=–2.768, P=0.006) and difficulty maintaining sleep (z=–2.502, P=0.012) groups, and less correct numbers of the word-delayed recognition compared to the difficulty maintaining sleep group too (z=–2.707, P=0.007). Conclusion: The procedural and declarative memories are impaired in the PI patients, especially the early morning awakening insomniacs.

Intact implicit verbal relational memory in medial temporal lobe amnesia

To elucidate the role of the hippocampus in unaware relational memory, the present study examined the performance of amnesic patients with medial temporal lobe (MTL) lesions on a cued category-exemplar generation task. In contrast to a prior study in which amnesic patients showed impaired performance (Verfaellie et al., Cognitive, Affective, and Behavioral Neuroscience, 2006, 6, 91–101), the current study employed a task that required active processing of the context word at test. In this version of the task, amnesic patients, like control participants, showed enhanced category exemplar priming when the context word associated with the target at study was reinstated at test. The finding of intact implicit memory for novel associations following hippocampal lesions in a task that requires flexible use of retrieval cues is inconsistent with a relational memory view that suggests that the hippocampus is critical for all forms of relational memory, regardless of awareness. Instead, it suggests that unaware memory for within-domain associations does not require MTL mediation.

Encoding Tasks Dissociate the Effects of Divided Attention on Category-Cued Recall and Category-Exemplar Generation

The combined effects of encoding tasks and divided attention upon category-exemplar generation and category-cued recall were examined. Participants were presented with pairs of words each comprising a category name and potential example of that category. They were then asked to indicate either (i) their liking for both of the words or (ii) if the exemplar was a member of the category. It was found that divided attention reduced performance on the category-cued recall task under both encoding conditions. However, performance on the category-exemplar generation task remained invariant across the attention manipulation following the category judgment task. This provides further evidence that the processes underlying performance on conceptual explicit and implicit memory tasks can be dissociated, and that the intentional formation of category-exemplar associations attenuates the effects of divided attention on category-exemplar generation.

The Medial Temporal Lobe Supports Conceptual Implicit Memory

The medial temporal lobe (MTL) is generally thought to be critical for explicit, but not implicit, memory. Here, we demonstrate that the perirhinal cortex (PRc), within the MTL, plays a role in conceptually-driven implicit memory. Amnesic patients with MTL lesions that converged on the left PRc exhibited deficits on two conceptual implicit tasks (i.e., exemplar generation and semantic decision). A separate functional magnetic resonance imaging (fMRI) study in healthy subjects indicated that PRc activation during encoding of words was predictive of subsequent exemplar generation. Moreover, across subjects, the magnitude of the fMRI and behavioral conceptual priming effects were directly related. Additionally, the PRc region implicated in the fMRI study was the same region of maximal lesion overlap in the patients with impaired conceptual priming. These patient and imaging results converge to suggest that the PRc plays a critical role in conceptual implicit memory, and possibly conceptual processing in general.

Conceptual and non-conceptual repetition priming in category exemplar generation: Evidence from bilinguals

One measure of conceptual implicit memory is repetition priming in the generation of exemplars from a semantic category, but does such priming transfer across languages? That is, do the overlapping conceptual representations for translation equivalents provide a sufficient basis for such priming? In Experiment 1 (N=96) participants carried out a deep encoding task, and priming between languages was statistically reliable, but attenuated, relative to within-language priming. Experiment 2 (N=96) replicated the findings of Experiment 1 and assessed the contributions of conceptual and non-conceptual processes using a levels-of-processing manipulation. Words that underwent shallow encoding exhibited within-language, but not between-language, priming. Priming in shallow conditions cannot therefore be explained by incidental activation of the concept. Instead, part of the within-language priming effect, even under deep-encoding conditions, is due to increased availability of language-specific lemmas or phonological word forms.

Conceptual implicit memory impaired in amnestic mild cognitive impairment patient

Explicit memory has been well proven to be impaired in amnestic mild cognitive impairment (aMCI), and conceptual implicit memory is impaired in Alzheimer's disease. However, it is unclear whether implicit memory is affected in aMCI. In the present study, 35 patients with aMCI and 35 healthy elderly subjects were administered a neuropsychological battery of tests including conceptual and perceptual implicit memory tasks (category exemplar generation, image identification) as well as explicit memory tasks. Patients with aMCI exhibited impairment in explicit memory tasks and selective impairment in conceptual priming tasks, while the effect of perceptual priming was preserved. More importantly, category exemplar generation task priming, but not perceptual priming, was positively correlated with verbal fluency test performance in the aMCI group. The dissociation between the 2 components of implicit priming suggests that conceptual priming impairment in aMCI patients may be related to frontal lobe dysfunction.

Measuring automatic retrieval in a conceptual priming task

The speeded response technique has demonstrated that priming in perceptual memory tasks can occur through automatic retrieval that is uncontaminated by conscious retrieval (pure automatic retrieval). This work assesses whether priming in a conceptual task (category exemplar generation) can occur through pure automatic retrieval using the same technique. Automatic retrieval estimates obtained using the speeded response technique were compared to those obtained using more traditional measures (implicit memory and process dissociation procedure [PDP]). Similar estimates of automatic retrieval were obtained for speeded, implicit, and PDP groups following shallow processing. However, higher estimates of automatic retrieval were obtained following deep processing in the speeded and implicit conditions compared to the PDP condition. Advantages for using the speeded response technique to index automatic memory are discussed.

Environmental context effects in conceptual explicit and implicit memory

Previous research has found environmental context effects for both conceptual explicit and conceptual implicit memory (Parker, Gellatly, & Waterman, 1999). The research presented here challenges these findings on methodological grounds. Experiment 1 assessed the effects of context change on category-exemplar generation (conceptual implicit memory test) and category-cued recall (conceptual explicit memory test). Experiment 2 assessed the effects of context change on word association (conceptual implicit memory test) and word associate cued recall (conceptual explicit memory test). In both experiments, study–test changes in environmental context were found to influence performance only on tests of explicit memory. It is concluded that when retrieval cues across explicit and implicit tests are matched, and the probability of explicit contamination is reduced, then only conceptual explicit test performance is reduced by study–test changes in environmental context.