Atypical Items Research Articles

How does typicality of category members affect the deductive reasoning? An ERP study

The typicality effect describes a phenomenon whereby a typical item is easier to be judged as a member of a category than are atypical items. This effect has been intensively studied in the context of category verification tasks. The present study further investigated the typicality effect using our newly developed category-based deductive reasoning task. Subjects were required to judge whether an incoming stimulus had the properties described in the premise presented before. The stimuli were either typical or atypical members of four target semantic categories or were non-target stimuli. According to the ERP results, three phases were needed to determine whether the object has the property associated with the category in the premise. First, significant amplitude differences were seen between typical and atypical items at N1, which suggested that attention processing was influenced by the expectation in this up-to-down (deductive) process. The premise automatically induced the expectation of the prototype of one concept, i.e. the expectation for the prototype of birds was induced when the premise was "Birds possess the property C". Typical items (e.g., sparrow) were more similar to the prototype; hence, they were easier to be matched with the prototype induced by the premise than were atypical items (e.g., ostrich). Additionally, there was a dissociation between typical and atypical items at P2, which suggested that the participants' early detection of an item's category membership was influenced by the typicality. Thirdly, N400 effect is related to the process of semantic processes and determining whether the object has the property associated with the category in the premise. N400 mean amplitudes during the 300-500 ms epoch were significantly greater for non-target members than for target members, while words of lower typicality (atypical) evoked greater N400 amplitudes during the 350-450 ms epoch than did words of higher typicality (typical).

Semantic Complexity in Treatment of Naming Deficits in Aphasia: Evidence From Well-Defined Categories

Our previous work on manipulating typicality of category exemplars during treatment of naming deficits has shown that training atypical examples generalizes to untrained typical examples but not vice versa. In contrast to natural categories that consist of fuzzy boundaries, well-defined categories (e.g., shapes) have rigid category boundaries. Whether these categories illustrate typicality effects similar to natural categories is under debate. The present study addressed this question in the context of treatment for naming deficits in aphasia. Using a single-subject experiment design, 3 participants with aphasia received a semantic feature treatment to improve naming of either typical or atypical items of shapes, while generalization was tested to untrained items of the category. For 2 of the 3 participants, training naming of atypical examples of shapes resulted in improved naming of untrained typical examples. Training typical examples in 1 participant did not improve naming of atypical examples. All 3 participants, however, showed weak acquisition trends. Results of the present study show equivocal support for manipulating typicality as a treatment variable within well-defined categories. Instead, these results indicate that acquisition and generalization effects within well-defined categories such as shapes are overshadowed by their inherent abstractness.

Typicality of Inanimate Category Exemplars in Aphasia Treatment: Further Evidence for Semantic Complexity

The typicality treatment approach on improving naming was investigated within 2 inanimate categories (furniture and clothing) using a single-subject experimental design across participants and behaviors in 5 patients with aphasia. Participants received a semantic feature treatment to improve naming of either typical or atypical items within semantic categories, whereas generalization was tested to untrained items of the category. The order of typicality and category trained was counterbalanced across participants. Results indicated that 2 out of 4 patients trained on naming of atypical examples demonstrated generalization to naming untrained typical examples. One patient showed trends toward generalization but did not achieve criterion. Furthermore, all 4 patients trained on typical examples demonstrated no generalized naming to untrained atypical examples within the category. Also, analysis of errors indicated an evolution of errors as a result of treatment, from those with no apparent relationship to the target to primarily semantic and phonemic paraphasias. These results extend our previous findings (S. Kiran & C. K. Thompson, 2003a) to patients with nonfluent aphasia and to inanimate categories such as furniture and clothing. Additionally, the results provide support for the claim that training atypical examples is a more efficient method of facilitating generalization to untrained items within a category than training typical examples (S. Kiran, 2007).

Osmotic-Release Oral System Methylphenidate Augmentation of Antidepressant Monotherapy in Major Depressive Disorder

To evaluate the efficacy, safety, and tolerability of adjunctive osmotic-release oral system (OROS) methylphenidate in outpatients with major depressive disorder (MDD) receiving a stable oral antidepressant regimen. This multicenter, double-blind, randomized, placebo-controlled, parallel-group, 5-week trial enrolled 145 subjects who met DSM-IV-TR criteria for MDD and who had failed 1 to 3 previous antidepressant monotherapies (including current antidepressant) of adequate dose and duration. Augmentation therapy was initiated with 18 mg of OROS methylphenidate and increased to a maximum dose of 54 mg of OROS methylphenidate until an optimal dose was achieved. Efficacy scales included the Montgomery-Asberg Depression Rating Scale (MADRS), 7 atypical items from the 31-item Hamilton Rating Scale for Depression, the Clinical Global Impressions-Severity of Illness (CGI-S) scale, the CGI-Improvement scale (CGI-I), the Sex Effects scale, the Multidimensional Assessment of Fatigue (MAF) scale, and the Apathy Evaluation Scale (AES). Subjects were recruited at 17 community and academic centers across Canada. The study was conducted from June 8, 2005, to April 18, 2006. There was no statistically significant difference between the groups at endpoint on the MADRS. OROS methylphenidate was superior to placebo in improving apathy and fatigue as measured by the AES and the MAF. Statistically significant differences using mixed-model analysis were observed on the AES at all visits and at endpoint (p = .01) and on the MAF (p < .01). No differences were observed on other secondary measures, including the CGI-I and CGI-S. There were no clinically significant findings on electrocardiogram. OROS methylphenidate did not demonstrate statistical significance on the MADRS at endpoint. Apathy and fatigue were significantly improved with OROS methylphenidate treatment, which was well tolerated with minimal side effects. ClinicalTrials.gov identifier NCT00246233.

Effect of typicality of ad hoc categories in lexical access

Ten normal young, ten normal older, and ten aphasic individuals participated in an online category verification task where primes were ad hoc category labels while targets were typical examples, atypical examples, nonmembers or nonwords. Results indicated that for all the three groups, accuracy and reaction time of atypical items was significantly worse than all other response types (p<.001). Additionally, the accuracy and reaction time of aphasic patients were significantly worse on all items compared to young and older adults (p<.001). The results of the present experiment illustrate typicality effect in ad hoc categories.

Prototypicality in sentence production

Three cued-recall experiments examined the effect of category typicality on the ordering of words in sentence production. Past research has found that typical items tend to be mentioned before atypical items in a phrase—a pattern usually associated with lexical variables (like word frequency), and yet typicality is a conceptual variable. Experiment 1 revealed that an appropriate conceptual framework was necessary to yield the typicality effect. Experiment 2 tested ad hoc categories that do not have prior representations in long-term memory and yielded no typicality effect. Experiment 3 used carefully matched sentences in which two category members appeared in the same or in different phrases. Typicality affected word order only when the two words appeared in the same phrase. These results are consistent with an account in which typicality has its origin in conceptual structure, which leads to differences in lexical accessibility in appropriate contexts.

Complexity in the Treatment of Naming Deficits

This article discusses a novel approach for treatment of lexical retrieval deficits in aphasia in which treatment begins with complex, rather than simple, lexical stimuli. This treatment considers the semantic complexity of items within semantic categories, with a focus on their featural detail. Method and Results Previous work on training items within animate categories (S. Kiran & C. K. Thompson, 2003b) and preliminary work aimed at items within inanimate categories are discussed in this article. Both these studies indicate that training atypical category items that entail features inherent in the category prototype as well as distinctive features that are not characteristic of the category prototype results in generalization to untrained typical examples which entail only features consistent with the category prototype. Conversely, training typical examples does not result in generalization to untrained atypical examples. In this article, it is argued that atypical items are more complex than typical items within a category, and a theoretical framework for this dimension of semantic complexity is discussed. Then, evidence from treatment studies that support this complexity hierarchy is presented. Potential patient- and stimulus-specific factors that may influence the success of this treatment approach are also discussed. The applications of semantic complexity to treatment of additional semantic categories and functional applications of this approach are proposed.

The influence of schematic knowledge on contradictory versus additive misinformation: false memory for typical and atypical items

AbstractIn the current study, we examined the influence of schema consistency on contradictory and additive misinformation. Sixty‐four participants were shown a series of still photographs of common scenes (e.g., a kitchen), were later exposed to narratives containing misinformation, and were then tested on their memory of the photographic scenes. In addition, participants were asked to reflect on their phenomenological experience of remembering by giving remember/know responses. Participants reported greater false memory for schema‐inconsistent items than schema‐consistent items. The findings failed to replicate Roediger, Meade, and Bergman (2001). Explanations for the discrepant findings are discussed. Copyright © 2006 John Wiley &amp; Sons, Ltd.

Age of acquisition and typicality effects in three object processing tasks

Eight experiments are reported that investigate the effects of age of acquisition (AoA) and typicality in three object processing tasks—object naming, object decision, and category verification. AoA influenced object naming under standard, immediate naming conditions and when participants had been pretrained on the pictures and their names, but there was no effect in a delayed naming task (Experiments 1, 5, and 6). Late acquired items of high typicality were named faster than those of low typicality when naming was unprimed but not when primed by pre-exposure to the items. Object decision speed (Is this a real object or not?) was faster to early than to late acquired items (Experiments 2, 3, and 7). That effect was reduced but not eliminated by articulatory suppression (Experiment 7). RTs were also faster to typical than to atypical items. That effect also interacted with AoA but was unaffected by suppression (Experiment 7). Category verification (Is this object a member of a named category?) showed an effect of AoA on positive but not negative decisions when typicality was not controlled (Experiment 4) but that effect disappeared once AoA was controlled (Experiment 8). Category verification was faster for typical than atypical items (Experiment 8). The findings are discussed in terms of theories of the influence of AoA and typicality on object recognition and naming.

Typicality‐based learning and generalisation in aphasia: Two case studies of anomia treatment

Background: Simulation models (Plaut, 1996) and anomia treatment (Kiran & Thompson, 2003b) have found that training with atypical items resulted in greater generalisation than training with typical items. The Complexity Account of Treatment Efficacy (CATE) predicts that therapy will produce greater generalisation when more complex items are trained (Thompson, Shapiro, Kiran, & Sobeck, 2003). Furthermore, learning and generalisation may be maximised when semantic training is directed towards semantic deficits (Plaut, 1996). The authors would like to thank SA and RB for their participation in and commitment to this project. Aims: The clinical application of Plaut's model and the CATE was investigated in typicality‐based learning and generalisation, following anomia treatment in one participant with mainly phonological deficits and one participant with both phonological and semantic deficits. Methods & Procedures: Participants were trained with a semantic treatment to name typical items in one semantic category and atypical items of a different semantic category. Typicality‐based learning and generalisation were compared. Outcomes & Results: The participant with primarily phonological deficits learned typical items faster than atypical items, and showed no generalisation to untrained items. The participant with phonological and semantic deficits learned both typical and atypical items, and showed significant generalisation to untrained typical items and marginally significant generalisation to untrained atypical items. Conclusions: Our results suggest that typical items may be easier to learn than atypical items when the semantic system is intact; however, typical items may be more difficult to learn with impairments in semantic knowledge and/or semantic selection, as these items have highly similar semantic features. Additionally, correspondence between the deficit and treatment may enhance learning and generalisation, as semantic treatment resulted in greater learning and generalisation for the participant with semantic deficits. Finally, family resemblance within semantic categories may produce generalisation to typical or atypical category members, but training with atypical members may produce more global changes within the semantic network, leading to greater generalisation.

“Presemantic” Cognition in Semantic Dementia: Six Deficits in Search of an Explanation

Abstract On the basis of a theory about the role of semantic knowledge in the recognition and production of familiar words and objects, we predicted that patients with semantic dementia would reveal a specific pattern of impairment on six different tasks typically considered “pre-” or “non-” semantic: reading aloud, writing to dictation, inflecting verbs, lexical decision, object decision, and delayed copy drawing. The prediction was that all tasks would reveal a frequency-by-typicality interaction, with patients performing especially poorly on lower-frequency items with atypical structure (e.g., words with an atypical spelling-to-sound relationship; objects with an atypical feature for their class, such as the hump on a camel, etc). Of 84 critical observations (14 patients performing 6 tasks), this prediction was correct in 84/84 cases; and a single component in a factor analysis accounted for 87% of the variance across seven measures: each patient's degree of impairment on atypical items in the six experimental tasks and a separate composite score reflecting his or her degree of semantic impairment. Errors also consistently conformed to the predicted pattern for both expressive and receptive tasks, with responses reflecting residual knowledge about the typical surface structure of each domain. We argue that these results cannot be explained as associated but unrelated deficits but instead are a principled consequence of a primary semantic impairment.

"Presemantic" Cognition in Semantic Dementia: Six Deficits in Search of an Explanation

On the basis of a theory about the role of semantic knowledge in the recognition and production of familiar words and objects, we predicted that patients with semantic dementia would reveal a specific pattern of impairment on six different tasks typically considered "pre-" or "non-" semantic: reading aloud, writing to dictation, inflecting verbs, lexical decision, object decision, and delayed copy drawing. The prediction was that all tasks would reveal a frequency-by-typicality interaction, with patients performing especially poorly on lower-frequency items with atypical structure (e.g., words with an atypical spelling-to-sound relationship; objects with an atypical feature for their class, such as the hump on a camel, etc). Of 84 critical observations (14 patients performing 6 tasks), this prediction was correct in 84/84 cases; and a single component in a factor analysis accounted for 87% of the variance across seven measures: each patient's degree of impairment on atypical items in the six experimental tasks and a separate composite score reflecting his or her degree of semantic impairment. Errors also consistently conformed to the predicted pattern for both expressive and receptive tasks, with responses reflecting residual knowledge about the typical surface structure of each domain. We argue that these results cannot be explained as associated but unrelated deficits but instead are a principled consequence of a primary semantic impairment.

Providing Access to Atypical Items in an Academic Library

In response to the University of Calgary librarians' concerns regarding access policies for atypical items, the relevant literature was examined and Canadian universities surveyed. Operating within the specific university context and the general principle of maximization of access and availability, guiding principles and specific criteria were developed for four categories of atypical items (controversial and desirable; items that need special handling; costly items; and collections of special significance). Recommendations are made for controlled access for each category.

Age-related improvements in a conceptual implicit memory test

The present study investigated developmental improvements in category exemplar generation priming in children from kindergarten to older elementary school age. The strength of categorical links for atypical exemplars increases in this age range, whereas category knowledge for typical exemplars remains relatively stable. Therefore, in comparison with older children, younger children should show less categorical-relational encoding and, thus, less priming for atypical items but not for typical items. This expectation was confirmed in Experiment 1. In Experiment 2, picture versus word format at study dissociated implicit and explicit performance, indicating that the age-related increase in priming for atypical exemplars in Experiment 1 was not an artifact of explicit contamination. The findings suggest that developmental improvements in conceptual priming can be observed when the conceptual knowledge relevant for a given task improves over the age range tested.

The role of semantic complexity in treatment of naming deficits: training semantic categories in fluent aphasia by controlling exemplar typicality.

The effect of typicality of category exemplars on naming was investigated using a single subject experimental design across participants and behaviors in 4 patients with fluent aphasia. Participants received a semantic feature treatment to improve naming of either typical or atypical items within semantic categories, while generalization was tested to untrained items of the category. The order of typicality and category trained was counterbalanced across participants. Results indicated that patients trained on naming of atypical exemplars demonstrated generalization to naming of intermediate and typical items. However, patients trained on typical items demonstrated no generalized naming effect to intermediate or atypical examples. Furthermore, analysis of errors indicated an evolution of errors throughout training, from those with no apparent relationship to the target to primarily semantic and phonemic paraphasias. Performance on standardized language tests also showed changes as a function of treatment. Theoretical and clinical implications regarding the impact of considering semantic complexity on rehabilitation of naming deficits in aphasia are discussed.

The role of semantic complexity in treatment of naming deficits: training semantic categories in fluent aphasia by controlling exemplar typicality.

The effect of typicality of category exemplars on naming was investigated using a single subject experimental design across participants and behaviors in 4 patients with fluent aphasia. Participants received a semantic feature treatment to improve naming of either typical or atypical items within semantic categories, while generalization was tested to untrained items of the category. The order of typicality and category trained was counterbalanced across participants. Results indicated that patients trained on naming of atypical exemplars demonstrated generalization to naming of intermediate and typical items. However, patients trained on typical items demonstrated no generalized naming effect to intermediate or atypical examples. Furthermore, analysis of errors indicated an evolution of errors throughout training, from those with no apparent relationship to the target to primarily semantic and phonemic paraphasias. Performance on standardized language tests also showed changes as a function of treatment. Theoretical and clinical implications regarding the impact of considering semantic complexity on rehabilitation of naming deficits in aphasia are discussed.

Elasticity and confabulation in schizophrenic delusions.

This experiment examines two aspects of delusional cognition that have been reported clinically but not investigated empirically. These are the incorporation of potentially conflicting information into the recall of delusion-related scripts and the type and amount of material produced additional to that presented for recall, referred to here as confabulation. Three groups of patients--deluded schizophrenics, non-deluded schizophrenics and matched non-psychiatric controls--were asked to recall two 15-item scripts, which comprised 10 typical and five atypical components. It was hypothesized that deluded subjects whose delusion was relevant to one of the scripts would recall more of the atypical components of the script and would also be less likely to make script-atypical confabulations in the recall of this particular script. Recall was assessed for the amount and type of content remembered and the amount and type of confabulation. The results did not support the hypothesis that atypical items would be incorporated into the recall of delusion-relevant material. However, deluded subjects did retain their schema boundaries in the recall of script items relevant to their own delusion but were less able to adhere to a script framework in the recall of material unrelated to their delusion. These results are discussed within a schema specific account of delusions, which conceptualizes the delusion as an overused schema whose preferential use leads to a failure to develop other scripts but whose own contents remain well-defined.

Category typicality effects in episodic memory: testing models of distinctiveness.

Category typicality effects were investigated within the context of three models of distinctiveness: a univariate model, a fixed-multifeature model, and a weighted-multifeature model. High-typical, medium-typical, and atypical targets were embedded in lists containing a background set of medium- to high-typicality items. Atypical items were more poorly recalled than were medium- and high-typical items independently of list structure. In recognition, subjects who studied high-typical items had difficulty discriminating between high-typical items that were and were not presented as part of the list. However, item typicality had little effect on the recognition performance of subjects who did not study high-typical items. These findings were consistent with the weighted-multifeature model of distinctiveness.

Gender-Schema Development and Children's Constructive Story Memory: Evidence for a Developmental Model

The objectives of the present research were to (a) provide a developmental model based on script research for describing how changes in memory for gender-related information are related to changes in gender-role stereotypes, (b) examine developmental differences in the effect of stereotype manipulations on the construction of new memories, and (c) examine the relation between stereotyped activity preferences and memory for gender-related information. 4-, 6-, and 8-year-olds listened to a story in which characters performed behaviors typical and atypical of gender-role stereotypes. An introduction preceded the story in which story characters' activities and preferences were described as either consistent or inconsistent with gender-role stereotypes. Dependent variables were the percentage of typical and atypical story items correctly recognized and the percentage of false alarms made for new items. Gender-role knowledge, stereotyped preferences, and gender-role flexibility were assessed. Results for false alarms, but not hit rates, supported the hypotheses of the model: (a) 6-year-olds falsely recognized typical distractors more than atypical distractors (this effect was nonsignificant for 4- and 8-year-olds), (b) false alarms for atypical distractors decreased between ages 4 and 6, and (c) false alarms for typical distractors decreased between ages 6 and 8. Contrary to expectation, stereotype manipulation effects did not interact with age, but were influenced by gender. Stereotyped preferences were strongly related to memory for gender-related information for both males and females. Results are discussed in terms of developmental and individual differences in gender-schema strength and composition.

Remembering to remember: adult age differences in prospective memory.

Age-related differences in prospective memory were examined in a laboratory-based task in which younger and older adults performed different actions whenever a semantically defined target word occurred in the context of a free-association task. Requirements for self-initiated retrieval operations were manipulated by presenting target words that were typical or atypical instances (e.g., milk vs ink) of a given semantic category (liquid). The results showed that age differences in prospective memory were accentuated when atypical items were used as targets, but reduced when highly typical targets were presented. Furthermore, age differences were not limited to remembering when to perform action, but young subjects also showed better performance in remembering what was to be done. These findings indicate that the magnitude of age difference in prospective memory interacts with task complexity, and support the view that prospective memory failures are accentuated in tasks with high resource demands on self-initiated retrieval operations.