Inferring category attributes from exemplar attributes: geometric shapes and social categories

Three experiments tested the hypothesis that judgments about the attributes of categories are disproportionately based on the characteristics of exemplars that best fit the category. In the first 2 experiments, subjects were presented with good and bad exemplars of categories with defining attributes (rectangles, triangles, pentagons, and ellipses) in which different colors were arbitrarily paired with the good and poor examples. In both experiments, subjects erroneously judged the colors paired with the good exemplars as more frequent than colors paired with the poor exemplars. A third experiment, using social categories, examined whether attributes associated with a single category member were more likely to generalize to the category as a whole for prototypical than for nonprototypical category members. Subjects were presented with information about individual fraternity members who varied in prototypicality, and the tendency to infer a target behavior (liberal vs. conservative voting behavior) from the individual fraternity member to the fraternity as a whole increased with the prototypicality of the category member. Implications for the contact hypothesis, category-exemplar relations, and belief stability are discussed.     

Prototypicality norms for 28 semantic categories

The extent to which an item is a prototypical exemplar of a category has been found to predict several experimental results (e.g., reaction times in category classification, free and cued recall of lists, release from proactive inhibition in recall). We present prototypicality ratings for 840 words, equally distributed over 28categories. Thecategories were taken from Battig and Montague’s (1969) normative tables; only those categories that contained “concrete” items in common usage were employed in the study. Intragroup reliability correlations were high for all categories tested, as were the correlations for prototypicality ratings between the present study and that of Rosch (1975). In addition, correlations between prototypicality ratings, production frequencies, and word frequencies of the items are given.     

The relationship between category typicality and concept familiarity: Evidence from Spanish- and English-speaking monolinguals

We examined the relationship between an item’s familiarity and its category typicality, employing ratings obtained from Spanish- and English-speaking monolinguals living in southern Florida. In the first experiment, Spanish- and English-speaking monolinguals were asked to rate the prototypicality of instances of 12 common language categories. The correlations between the Spanish and English speakers’ rated item typicality indicated that the prototypicality gradients of the Spanish and English monolinguals were fairly discrepant for a number of categories. In the second experiment, we examined the degree to which these differences in cultural typicality could be accounted for by differences in rated cultural familiarity. It was predicted that, if familiarity plays a role in determining cultural differences in prototypicality, statistically controlling for the effects of cultural familiarity should result in higher interlingual typicality correlations. This should be true particularly for those categories for which there is a wide discrepancy in the typicality gradients for the two language groups. These predictions were confirmed. Consequently, we conclude that item familiarity is at least one variable influencing cultural differences in category typicality gradients.     

Proximity to central tendency and usefulness in attaining goals as predictors of prototypicality for behaviour-descriptive categories

This study investigated determinants of the internal structure of categories of directed behaviours. For the categories Sport, Gardening, Craft, Making music, and Housekeeping, proximity to the category's central tendency and usefulness in accomplishing category-specific goals were compared as predictors of prototypicality ratings. In a preliminary study, subjects suggested activities and goals for the five categories. In the main study, subjects estimated the prototypicality of these activities for the categories, their usefulness in attaining the category-specific goals, and the similarity of the activities among each other. Family resemblance scores were derived from the latter ratings. It was found that family resemblance and usefulness in attaining category-specific goals were about equally useful in predicting the actual prototypicality ratings.     

On the equivalence of superordinate concepts

Psychological studies of superordinates have generally treated them as equivalent. However, many languages distinguish mass superordinates (e.g., clothing) from count superordinates (e.g., vehicle). In the present paper, experimental evidence is presented which suggests that the two types of superordinates are conceptually distinct as well. One study showed that the members of mass superordinates more often co-occur. A second study showed that people more often interact with the members of mass superordinates in temporal proximity whereas people primarily interact with single members of count superordinates on a specific occasion. Also, properties that characterize an individual are a more salient aspect of count superordinates. These findings imply that mass superordinates refer to unindividuated groups of objects, united by spatial and functional contiguity. Two other studies supported this hypothesis by showing that the class inclusion relation between a single object and a category is stronger for count superordinates. Taken together, the findings suggest that mass superordinates are not true taxonomic categories. We relate the findings to previous views of superordinates and to the count/mass distinction in general.     

Sorting out categories: Incremental learning of category structure

Two experiments examine how inferences might promote unsupervised and incremental category learning. Many categories have members related through overall similarity (e.g., a family resemblance structure) rather than by a defining feature. However, when people are asked to sort category members in a category construction task, they often do so by partitioning on a single feature. Starting from an earlier result showing that pairwise inferences increase family resemblance sorting (Lassaline & Murphy, 1996), we examine how these inferences lead to learning the family resemblance structure. Results show that the category structure is learned incrementally. The pairwise inferences influence participants’ weightings of feature pairs that were specifically asked about, which in turn affects their sorting. The sorting then allows further learning of the categorical structure. Thus, the inferences do not directly lead learners to the family resemblance structure, but they do provide a foundation to build on as the participants make additional judgments.     

The game of the name: An examination of linguistic reference after brain damage

Two aspects of naming have generally been examined in aphasics: the appreciation of a single property of a concept and the ability to use the names of fully elaborated concepts. In applying to aphasics a recently proposed model of semantic organization—one which allows the simultaneous examination of these two aspects—two studies were conducted: Anterior and posterior aphasics were asked (1) to name members of superordinate categories, their responses being converted into prototypicality scores (the degree to which a member of a category resembles an ideal member of that category) and (2) to differentiate between more or less prototypical members of a category and their superordinates. The results revealed that, while anterior and posterior aphasics differ in their use of the names representing fully elaborated concepts, these groups show no differences in terms of the appreciation of a single property of a concept. The implications of these findings for reference were discussed.     

Basic-level visual similarity and category specificity

The role of visual crowding in category deficits has been widely discussed (e.g.,;; ). Most studies have measured overlap at the superordinate level (compare different examples of 'animal') rather than at the basic level (compare different examples of 'dog'). In this study, we therefore derived two measures of basic-level overlap for a range of categories. The first was a computational measure generated by a self-organising neural network trained to process pictures of living and non-living things; the second was a rating of perceived visual similarity generated by human subjects to the item names. The computational measure indicated that the pattern of crowded/uncrowded does not honour a living/non-living distinction. Nevertheless, different superordinates showed varied degrees of basic-level overlap, suggesting that specific token choice affects some superordinates more than others e.g., individual fruit and vegetable tokens show greater variability than any other items, while tools and vehicles produce more reliable or overlapping basic-level visual representations. Finally, subject ratings correlated significantly with the computational measures indicating that the neural model represents structural properties of the objects that are psychologically meaningful.     

Testing the speech unit hypothesis with the primed matching task: Phoneme categories are perceptually basic

The basic speech unit (phoneme or syllable) problem was investigatedwith the primed matching task. In primed matching, subjects have to decide whether the elements of stimulus pairs are the same or different. The prime should facilitate matching in as far as its representation is similar to the stimuli to be matched. If stimulus representations generate graded structure, with stimulus instances being more or less prototypical for the category, priming should interact with prototypicality because prototypical instances are more similar to the activated category than are low-prototypical instances. Rosch (1975a, 1975b) showed that, by varying the matching criterion (matching for physical identity or for belonging to the same category), the specific patterns of the priming × prototypicality interaction could differentiate perceptually based from abstract categories. Bytesting this pattern forphoneme and syllable categories, the abstraction level of these categories canbe studied. After finding reliable prototypicality effects for both phoneme and syllable categories (Experiments 1 and 2), primed phoneme matching (Experiments 3 and 4) and primed syllable matching (Experiments 5 and 6) were used under both physical identity instructions and same-category instructions. The results make clear that phoneme categories are represented on the basis of perceptual information, whereas syllable representations are more abstract. The phoneme category can thus be identified as the basic speech unit. Implications for phoneme and syllable representation are discussed.     

Induction and category coherence

In studies of category formation, subjects rarely construct family resemblance categories. Instead, they divide objects into categories using a single dimension. This is a puzzling result given the widely accepted view that natural categories are organized in terms of a family resemblance principle. The observation that natural categories support inductive inferences is used here to test the hypothesis that family resemblance categories would be constructed if stimuli were first used to generate inductive inferences. In two experiments, subjects answered either induction questions, which made interproperty relationships more salient, or frequency questions, which required information only about individual properties, before they performed a sorting task. Subjects were likely to produce family resemblance sorts if they had first answered induction questions but not if they had answered frequency questions.     

Category dimensionality and feature knowledge: when more features are learned as easily as fewer

Three experiments compared the learning of lower-dimensional family resemblance categories (4 dimensions) with the learning of higher-dimensional ones (8 dimensions). Category-learning models incorporating error-driven learning, hypothesis testing, or limited capacity attention predict that additional dimensions should either increase learning difficulty or decrease learning of individual features. Contrary to these predictions, the experiments showed no slower learning of high-dimensional categories; instead, subjects learned more features from high-dimensional categories than from low-dimensional categories. This result obtained both in standard learning with feedback and in noncontingent, observational learning. These results show that rather than interfering with learning, categories with more dimensions cause individuals to learn more. The authors contrast the learning of family resemblance categories with learning in classical conditioning and probability learning paradigms, in which competition among features is well documented.     

A sequential cognitive diagnosis model for polytomous responses

This paper proposes a general polytomous cognitive diagnosis model for a special type of graded responses, where item categories are attained in a sequential manner, and associated with some attributes explicitly. To relate categories to attributes, a category‐level Q‐matrix is used. When the attribute and category association is specified a priori, the proposed model has the flexibility to allow different cognitive processes (e.g., conjunctive, disjunctive) to be modelled at different categories within a single item. This model can be extended for items where categories cannot be explicitly linked to attributes, and for items with unordered categories. The feasibility of the proposed model is examined using simulated data. The proposed model is illustrated using the data from the Trends in International Mathematics and Science Study 2007 assessment.     

Typhoid Pollyanna: The effect of category valence on retrieval order of positive and negative category members

Previous research suggests that people process pleasant information more efficiently than unpleasant information. This phenomenon has been illustrated in a variety of contexts and paradigms, and is frequently referred to as the Pollyanna principle. One important aspect of the Pollyanna principle is that people tend to retrieve pleasant members of a category from semantic memory prior to unpleasant members of the same category. However, we propose that the retrieval advantage of favourably viewed category members holds only for positive categories and that prototypicality of category members might be a better predictor of ease of retrieval than favourability. These possibilities were tested in two studies. In Study 1, favourability effects on retrieval order were observed for positive categories but not for neutral or negative categories. In Study 2, prototypical category members were retrieved before less prototypical category members for both positive and negative categories. These results suggest that the Pollyanna principle might be the result of a confound between favourability and prototypicality for members of favourable categories.     

Perceptual learning in visual category acquisition

The attribute structure of a set of dot patterns was studied by having subjects segment (parse) the dots of each pattern into parts or subunits by drawing circles around groups of dots from each pattern. These parsing data were obtained for subjects who had no prior experience with the patterns and for subjects who had previously learned to identify the patterns as members of one of four categories. Analyses of the parsing data indicated that category learning increased the salience of large subunits that were similar in orientation for patterns that were members of the same category. This evidence for perceptual learning was obtained even when the category training procedure required learning to identify the patterns individually, suggesting that attribute abstraction and item learning are not incompatible. It was also obtained without an increase in overall intersubject agreement. The latter result led us to question the usefulness of intersubject agreement as an index of category knowledge.     

Making Probabilistic Relational Categories Learnable

Theories of relational concept acquisition (e.g., schema induction) based on structured intersection discovery predict that relational concepts with a probabilistic (i.e., family resemblance) structure ought to be extremely difficult to learn. We report four experiments testing this prediction by investigating conditions hypothesized to facilitate the learning of such categories. Experiment 1 showed that changing the task from a category‐learning task to choosing the “winning” object in each stimulus greatly facilitated participants' ability to learn probabilistic relational categories. Experiments 2 and 3 further investigated the mechanisms underlying this “who's winning” effect. Experiment 4 replicated and generalized the “who's winning” effect with more natural stimuli. Together, our findings suggest that people learn relational concepts by a process of intersection discovery akin to schema induction, and that any task that encourages people to discover a higher order relation that remains invariant over members of a category will facilitate the learning of putatively probabilistic relational concepts.     

Basic objects in natural categories

Categorizations which humans make of the concrete world are not arbitrary but highly determined. In taxonomies of concrete objects, there is one level of abstraction at which the most basic category cuts are made. Basic categories are those which carry the most information, possess the highest category cue validity, and are, thus, the most differentiated from one another. The four experiments of Part I define basic objects by demonstrating that in taxonomies of common concrete nouns in English based on class inclusion, basic objects are the most inclusive categories whose members: (a) possess significant numbers of attributes in common, (b) have motor programs which are similar to one another, (c) have similar shapes, and (d) can be identified from averaged shapes of members of the class. The eight experiments of Part II explore implications of the structure of categories. Basic objects are shown to be the most inclusive categories for which a concrete image of the category as a whole can be formed, to be the first categorizations made during perception of the environment, to be the earliest categories sorted and earliest named by children, and to be the categories most codable, most coded, and most necessary in language.     

初中学生类别建构中的知识效应研究

采用类别建构的实验范式,选取具有家族相似性结构的人工类别材料,考察了已有知识对初中学生类别建构的影响。实验结果表明,当类别特征能够在已有知识的基础上形成主题时,初中学生倾向于按主题建构类别,而且在主题愈突出时这种趋势愈为明显;并且,主题性质对不同领域材料的类别建构的影响是一致的。     

Category-specificity can emerge from bottom-up visual characteristics: evidence from a modular neural network

The role of bottom-up visual processes in category-specific object recognition has been largely unexplored. We examined the role of low-level visual characteristics in category specific recognition using a modular neural network comprising both unsupervised and supervised components. One hundred standardised pictures from ten different categories (five living and five nonliving, including body parts and musical instruments) were presented to a Kohonen self-organising map (SOM) which re-represents the visual stimuli by clustering them within a smaller number of dimensions. The SOM representations were then used to train an attractor network to learn the superordinate category of each item. The ease with which the model acquired the category mappings was investigated with respect to emerging category effects. We found that the superordinates could be separated by very low-level visual factors (as extracted by the SOM). The model also accounted for the well documented atypicality of body parts and musical instrument superordinates. The model has clear relevance to human object recognition since the model was quicker to learn more typical category exemplars and finally the model also accounted for more than 20% of the naming variance in a sample of 57 brain injured subjects. We conclude that purely bottom-up visual characteristics can explain some important features of category-specific phenomena.     

Are rating-based procedures reliable for derivation of typicality judgments from children?

The aim of the present study was to examine whether a rating-based procedure that has already been used by other investigators can be used for derivation of typicality ratings from children. The evidence reported in the study establishes that such a procedure cannot be reliably used for this purpose. The results show that children rated category items in terms of personal preferences rather than as a function of how representative they considered the items to be of their superordinate category. On the basis of these findings, an alternative method based on the family resemblance scores of the category members was proposed in order to derive typicality ratings from young children. This family resemblance method of obtaining typicality judgments may be useful to investigators interested in assessing how children process categorical information.