Category Membership Judgments Research Articles

The idiosyncratic nature of how individuals perceive, represent, and remember their surroundings and its impact on learning-based generalization.

The current study adopted a multimodal assessment approach to map the idiosyncratic nature of how individuals perceive, represent, and remember their surroundings and to investigate its impact on learning-based generalization. During an online differential conditioning paradigm, participants (n = 105) learned the pairing between a blue color patch (CS +) and an outcome (i.e., shock symbol) and the unpairing between a green color patch and the same outcome. After the learning task, the generalization of outcome expectancies was assessed to 14 stimuli spanning the entire blue-green color spectrum. Hereafter, a stimulus identification task assessed the ability to correctly identify the CS + among this stimulus range. Continuous and binary color category membership judgments of the stimuli were assessed preconditioning. We found that a response model with color perception and identification performance as sole predictors was preferred to contemporary approaches that use stimulus as a predictor. Interestingly, incorporating interindividual differences in color perception, CS identification, and color categories significantly improved the models' ability to account for different generalization patterns. Our findings suggest that insight into the idiosyncratic nature of how individuals perceive, represent, and remember their surroundings provides exciting opportunities to understand post-learning behaviors better. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

A Context-Dependent Bayesian Account for Causal-Based Categorization.

The causal view of categories assumes that categories are represented by features and their causal relations. To study the effect of causal knowledge on categorization, researchers have used Bayesian causal models. Within that framework, categorization may be viewed as dependent on a likelihood computation (i.e., the likelihood of an exemplar with a certain combination of features, given the category's causal model) or as a posterior computation (i.e., the probability that the exemplar belongs to the category, given its features). Across three experiments, in combination with computational modeling, we offer evidence that categorization is better accounted for by assuming that people compute posteriors and not likelihoods, though both probabilities are closely related. This result contrasts with existing analyses of causal-based categorization, which assume that likelihood computations give a good approximation of human judgments. We also find that people are able to compute likelihoods in a closely related task that elicits judgments of consistency rather than category membership judgments. Our analyses show that people do use causal probabilistic information as prescribed by a Bayesian model but that they flexibly compute likelihoods or posteriors depending on the task. We discuss our results in relation to the relevant literature on the topic.

Normative Social Role Concepts in Early Childhood.

The current studies (N=255, children ages 4-5 and adults) explore patterns of age-related continuity and change in conceptual representations of social role categories (e.g., "scientist"). In Study 1, young children's judgments of category membership were shaped by both category labels and category-normative traits, and the two were dissociable, indicating that even young children's conceptual representations for some social categories have a "dual character." In Study 2, when labels and traits were contrasted, adults and children based their category-based induction decisions on category-normative traits rather than labels. Study 3 confirmed that children reason based on category-normative traits because they view them as an obligatory part of category membership. In contrast, adults in this study viewed the category-normative traits as informative on their own (not only as a cue to obligations). Implications for continuity and change in representations of social role categories will be discussed.

Feature taxonomy: What type of features do children associate with categories and how do they fare in predicting category judgments?

The present study investigates category intension in school-aged children and adults at two different levels of abstraction (i.e., superordinate and basic level) for two category types (i.e., artefacts and natural kinds). We addressed two critical questions: what kind of features do children and adults generate to define semantic categories and which features predict category membership judgment best at each abstraction level? Overall, participants generated relatively more entity features for natural kinds categories, compared to artefact categories, as well as for basic level categories, compared to superordinate categories. Furthermore, the results showed that older children and adults generated relatively more entity features than younger children. Finally, situation features play the most important role in the prediction of category judgments at both levels of abstraction. Theoretical implications and comparable results from previous studies are described in detail.

Category learning in Alzheimer’s disease and normal cognitive aging depends on initial experience of feature variability

Semantic category learning is dependent upon several factors, including the nature of the learning task, as well as individual differences in the quality and heterogeneity of exemplars that an individual encounters during learning. We trained healthy older adults (n=39) and individuals with a diagnosis of Alzheimer’s disease or Mild Cognitive Impairment (n=44) to recognize instances of a fictitious animal, a “crutter”. Each stimulus item contained 10 visual features (e.g., color, tail shape) which took one of two values for each feature (e.g., yellow/red, curly/straight tails). Participants were presented with a series of items (learning phase) and were either told the items belonged to a semantic category (explicit condition) or were told to think about the appearance of the items (implicit condition). Half of participants saw learning items with higher similarity to an unseen prototype (high typicality learning set), and thus lower between-item variability in their constituent features; the other half learned from items with lower typicality (low typicality learning set) and higher between-item feature variability. After the learning phase, participants were presented with test items one at a time that varied in the number of typical features from 0 (antitype) to 10 (prototype). We examined between-subjects factors of learning set (lower or higher typicality), instruction type (explicit or implicit), and group (patients vs. elderly control). Learning in controls was aided by higher learning set typicality: while controls in both learning set groups demonstrated significant learning, those exposed to a high-typicality learning set appeared to develop a prototype that helped guide their category membership judgments. Overall, patients demonstrated more difficulty with category learning than elderly controls. Patients exposed to the higher-typicality learning set were sensitive to the typical features of the category and discriminated between the most and least typical test items, although less reliably than controls. In contrast, patients exposed to the low-typicality learning set showed no evidence of learning. Analysis of structural imaging data indicated a positive association between left hippocampal grey matter density in elderly controls but a negative association in the patient group, suggesting differential reliance on hippocampal-mediated learning. Contrary to hypotheses, learning did not differ between explicit and implicit conditions for either group. Results demonstrate that category learning is improved when learning materials are highly similar to the prototype.

Are you as smart as a 4th grader? Why the prototypesimilarity approach to diagnosis is a step backward for a scientific psychiatry

Are you as smart as a 4th grader? Why the prototypesimilarity approach to diagnosis is a step backward for a scientific psychiatry

A processing approach to the working memory/long-term memory distinction: Evidence from the levels-of-processing span task.

Recent theories suggest that performance on working memory (WM) tasks involves retrieval from long-term memory (LTM). To examine whether WM and LTM tests have common principles, Craik and Tulving's (1975) levels-of-processing paradigm, which is known to affect LTM, was administered as a WM task: Participants made uppercase, rhyme, or category-membership judgments about words, and immediate recall of the words was required after every 3 or 8 processing judgments. In Experiment 1, immediate recall did not demonstrate a levels-of-processing effect, but a subsequent LTM test (delayed recognition) of the same words did show a benefit of deeper processing. Experiment 2 showed that surprise immediate recall of 8-item lists did demonstrate a levels-of-processing effect, however. A processing account of the conditions in which levels-of-processing effects are and are not found in WM tasks was advanced, suggesting that the extent to which levels-of-processing effects are similar between WM and LTM tests largely depends on the amount of disruption to active maintenance processes.

Packing: A geometric analysis of feature selection and category formation

This paper presents a geometrical analysis of how local interactions in a large population of categories packed into a feature space create a global structure of feature relevance. The theory is a formal proof that the joint optimization of discrimination and inclusion creates a smooth space of categories such that near categories in the similarity space have similar generalization gradients. Packing theory offers a unified account of several phenomena in human categorization including the differential importance of different features for different kinds of categories, the dissociation between judgments of similarity and judgments of category membership, and children’s ability to generalize a category from very few examples.

The Conceptual Separation of Food and Animals in Childhood

Nonhuman animals are primarily defined according to their form of relation with human beings, which broadly depends on the perceived utility of those animals to humans. These relations may be analyzed to generate typologies, membership of which circumscribes the probable fate of nonhuman animals when they enter into contact with humans. However, these judgments of utility and category membership are contingent and socially constructed, as demonstrated by cultural and historical variability in the species and individual animals assigned to particular types. This paper explores how the combination of childhood literary and film traditions relating to animals and associated promotional food tie-ins aimed at children contribute to a food socialization process whereby children learn to conceptually distance the animals they eat from those with whom they have an emotional bond or for whom they feel ethically responsible. In so doing, we develop a theoretical scheme for the differentiated positioning of animals.

Causal relations between features and inferences: The case of object representations

The theory-based conceptions of categorization postulate the existence of a network of causal relations between the features involved in object representations and consider that this network underpins both judgments of category membership and inference production. The aim of this article is to examine the proposed models (causal status, causal density) within the framework of theory-based conceptions and indicate how they account for inferential processes. Finally, we underline the importance of the task context, and of the role of the nature of the ontological domain for the theoretical modeling of a causal network based on an asymmetrical, probabilistic representation of causality.

See what I mean? An ERP study of the effect of background knowledge on novel object processing

Two event-related potential (ERP) experiments were used to examine the representation of object feature information and background knowledge in semantic memory. Participants were trained on novel object categories with three features and were tested with new exemplars that were complete or were missing one to two features that were essential or nonessential to object function. In both a category membership judgment task (Experiment 1) and a parts detection task (Experiment 2), the N400, a functionally specific measure of semantic access, was graded with feature number but was insensitive to knowledge-based feature importance. A separable ERP effect related to knowledge was seen in Experiment 1 as an enhanced frontocentral negativity (beginning approximately 300 msec) to exemplars missing a nonessential versus an essential feature, but this effect did not manifest when background knowledge was less task relevant (Experiment 2). Thus, similarity- and knowledge-based effects are separable, and the locus of knowledge effects varies with task demands but does not seem to arise from facilitated semantic access.

Semantic categorisation of novel objects in frontotemporal dementia

Impaired semantic memory is ubiquitous in frontotemporal dementia (FTD), including patients with semantic dementia (SD), progressive nonfluent aphasia (PNFA) and nonaphasic FTD patients with a deficit in executive and social functioning (EXEC/SOC). One hypothesis attributes this to the degradation of specific categories of knowledge in semantic memory. This study explores the alternate hypothesis that impaired semantic memory in FTD can also reflect limitations in the categorisation processes that determine object meaning. Patients were taught a novel semantic category under two conditions: rule-based categorisation, where executive resources support the evaluation of specific features to determine category membership; and similarity-based categorisation, where category membership is determined by the overall resemblance of an item to a prototype or recalled exemplars. In the first experiment, patients learned a novel category composed of highly salient features. For SD patients, we found category membership judgment profiles following rule-based and similarity-based training that resembled the performance of control subjects. Categorisation was impaired following rule-based training in PNFA and EXEC/SOC patients. In the second experiment, we modified the category so that membership was determined by less salient features, thus increasing the burden on executive resources. Under these circumstances, SD patients' categorisation profiles continued to resemble those of control subjects, PNFA patients' category judgments were governed by feature salience, and EXEC/SOC patients' judgments were limited by impaired executive resources. These observations suggest that the semantic memory deficit in SD largely reflects degraded feature knowledge for familiar objects, while impaired semantic memory in PNFA and in EXEC/SOC patients largely reflects a deficit in the processes associated with semantic categorisation. Portions of this work were presented at the Fourth International Meeting of Frontotemporal Dementia in Lund, Sweden, April 2003.

P2-210 Regional MR brain volumes in the prediction of cognitive decline in ad

P2-210 Regional MR brain volumes in the prediction of cognitive decline in ad

Domain differences in absolute judgments of category membership: evidence for an essentialist account of categorization.

There has been some debate about the correspondence between typicality gradients and category membership. The present study investigates the relationship between these two measures in the domains of animals and artifacts. Forty-two adults judged the degree of typicality or category membership of 293 animals and artifacts. The subjects' tendency for animals, but not for artifacts, was to make more absolute ratings on category membership (i.e., judging exemplars as definitely members or definitely not members of their respective category) than on typicality. More importantly, at almost every level of typicality, subjects were more likely to make absolute judgments of category membership for animals than for artifacts. These results indicate that people treat category membership of animals as relatively absolute (which best fits an essentialist model of categorization) and treat category membership of artifacts as relatively graded (which best fits a prototype model of categorization). These domain differences add crucial supporting evidence for claims about the domain-specificity of essentialism.

Structure mapping in analogy and similarity.

ions Keil, 1989 ; Rips, 1989) . For example, bats have the perceptual and behavioral characteristics of birds (they are similar to birds in this sense), but they are classified as mammals, because of important (though nonobvious) properties, such as giving birth to live young. On the basis of examples like this, similarity's role in categorization has been challenged ; it has been argued that category membership judgments are theory based rather than similarity based (Keil, 1989 ; Murphy & Medin, 1985) . The process of alignment and mapping points the way to a reconciliation of similarity-based and theorybased accounts (see also Goldstone, 1994a) . If we focus purely on perceptual similarity among objects, we are led to conclude that bats should be categorized with birds . On this view, theory-based knowledge (such as why bats are mammals) must intervene from elsewhere to overrule this assignment . However, if the similarity computation is assumed to be that ofstructural alignment, then the similarity between two instances will be based riot only on object-level commonalities but also on common relations such as common causal relations and common origins . Assuming that our representations include information about theory-based relations, such as that bats bear live young, as well as information about features, then the schism between similarity-based and theory-based categorization may be more apparent than real . Developmentally, if we assume that theoretical knowledge is acquired gradually, this view would account for the characteristic-to-defining shift (Keil & Batterman, 1984) in children's interpretations of word meaning from local object features (e.g ., a taxi is bright yellow and has a checkered sign) to deeper relational commonalities (e.g ., a taxi is a vehicle that may be hired to transport people) . Choice and decision . Structural alignment also sheds light on the processes underlying choice behavior. Medin, Goldstone, and Markman (1995) reviewed paral lels between phenomena in decision processing and phenomena in comparison processing that suggest an important role for structural alignment in decision making . Structural alignment influences which features to pay attention to in choice options . Research suggests that alignable differences are given more weight in choice situations than are nonalignable differences (Lindemann & Markman, 1996 ; Markman & Medin, 1995 ; Slovic & MacPhillamy, 1974) . For example, Markman and Medin (1995) asked participants to choose between video games and to justify their choices. Their justifications were more likely to contain alignable differences than nonalignable differences . As another example, Kahneman and Z'versky (1984) described to participants a hypothetical store in which a jacket could be bought for $125 and a calculator for $15 . They offered participants the opportunity to go to another store and save $5 on the total purchase. Participants who were offered ajacket for $125 and a calculator for $10 were more willing to make the effort to go to another store than those offered a jacket for $120 and a calculator for $15 . Even though the monetary reward for going to the other store was the same for both groups, participants were influenced by the alignable difference .

Anomaly Judgments of Subject–Predicate Relations in Alzheimer's Disease

Claims that patients with probable Alzheimer's disease (AD) have semantic memory difficulty have received equivocal support. A common assumption has been that defining or core information determines the truth value of word meaning on measures requiring semantic memory such as category membership judgments or confrontation naming, but this assumption may not be valid. In the present study, we assessed the comprehension of subject–predicate sentences independent of their truth value by asking AD patients to judge the coherence of statements such as “The tulip is tall” or “*The tulip is jealous.” We found that AD patients are significantly more impaired than controls at judging the coherence of these simple subject–predicate sentences. Moreover, AD patients were more successful at judging the coherence of statements that contain attributes with a narrow scope of reference compared to attributes with a broad scope of reference. These findings support the hypothesis that AD patients have a semantic memory impairment and suggest a specific deficit processing the network of semantic relations underlying word meaning in semantic memory.

Water is Not H 2O

What makes a liquid water? A strong version of "psychological essentialism" predicts that people use the presence or absence of H 2O as the primary determinant of what liquids they call "water." To test this prediction, subjects were asked to judge the amount of H 2O in liquids called "water" and liquids not called "water." Neither their beliefs about the simple presence/absence of H 2O nor about the proportion of H 2O in the liquids accounted well for which ones are normally called "water." Typicality ratings and an extended tree solution on similarity ratings suggested that use, location, and source of a liquid may also influence whether it is considered to be water. Sentence acceptability judgments further suggested that there may be a sense of "water" that corresponds to the strong essentialist view, but that there is also a more general sense in common use encompassing mixtures with varying amounts of H 2O. These findings indicate that essentialist beliefs alone may not fully explain category membership judgments and word use, and they suggest a modified version of psychological essentialism.

Features and beliefs in the mental representation of categories

Simple concepts such as chair and bird are central to human cognition, but the nature of these mental representations is unclear. Accounts based on probabilistically associated features fail to account for certain observations about category membership judgments. On the other hand, the possibility that concepts consist of or even include defining features has received little empirical support. The work reported here argues that certain phenomena may not reflect the actual presence of defining features, but rather only the presence of a belief in such features. Further, concepts will not be uniform with respect to this belief: Some concepts will include a belief in defining features, but others will not. Five experiments explore these possibilities through two different experimental tasks based on judgments of sentence acceptability. Results support the idea that concepts include beliefs about the nature of the categories they represent, and that certain concepts (notably, many natural kind concepts) differ from others (notably, many common artifact concepts) in the nature of the beliefs held, even though defining features may not be explicitly represented in either.

On the relationship between category intensions and extensions in children

We contrasted four theories of natural language category acquisition by investigating the relation between category intensions and extensions in children (kindergarteners, second graders, fifth graders) and in college students. Everyone was asked to define a category term, to make category membership judgments of possible exemplars, and to judge whether the possible exemplars possessed features generated by them and by previous adult subjects. Adult judges were also asked to judge whether the possible exemplars possessed the features generated by the subjects. Children's intensions and extensions were very consistent. In addition, children's extensions were reliably smaller than adults', and the features which children generated were more specific than those generated by adults. None of the existing theories discussed can explain this pattern of results. An exemplar-based model is proposed to do so.

Stimulus categorization by brain-damaged patients

Patients with localized insult to the right hemisphere, or to either the anterior or the posterior portion of the left hemisphere, as well as neurologically intact controls, evaluated stimuli on a seven-point rating scale for their degree of category membership. The stimuli were taken from one of two continua, one composed of fruit and vegetable items, and the other of items differing in hue and shape. Different subsets of stimuli provided different contexts for the judgments of category membership. The two left-hemisphere groups showed anomalies in categorizing the fruit and vegetable items but not the perceptual items, while the reverse was true for the right-hemisphere patients. Moreover, both left-hemisphere groups demonstrated context effects in their judgments of the representativeness of the fruit and vegetable items, but differed in the way in which they responded to changing contexts. Left posterior patients demonstrated weak category boundaries and even reclassified items. In contrast, patients with left anterior damage showed highly categorical responses and less differentiation of items within a category. All groups showed striking context effects in judgments of perceptual items in terms of changes in representativeness ratings and the location of a category boundary. Alternative interpretations of the results are offered.