The effects of feature necessity and extrinsicity on gradedness of category membership and class inclusion relations*

Two theories of differences among natural language categories in graded membership and strength of class inclusion are contrasted. The two sets of hypotheses tested were: (1) that categories represented by features which many people believe to be necessary would have less graded memberships, and stronger class inclusion, than those represented by features which few people believe to be necessary, and (2) that categories which people believe are represented primarily by intrinsic features (i.e. features that are true of an entity in isolation; see Barr & Caplan, 1987) would have less graded structures, and stronger class inclusion, than those which people believe are represented primarily by extrinsic features (i.e. features representing relations between an entity and other entities). The findings suggest that feature necessity and feature extrinsicity have independent effects on gradedness of category membership and on class inclusion.     

Confidence and gradedness in semantic categorization: Definitely somewhat artifactual,maybe absolutely natural

Artifacts tend to be categorized in a graded (i.e., continuous) manner, whereas natural categorization tends to be absolute (i.e., discrete). This domain-specific categorization is assumed to reflect a domain difference in representation. However, another tenable but untested explanation is that graded categorization arises from uncertainty, which is greater in artifact categories than in natural categories. Confidence ratings were used as an index of certainty in two experiments that tested whether confidence in category judgments can explain the apparent gradedness of those categories. Both experiments revealed that artifact categories were more graded and were judged with greater confidence than were natural categories. Confidence and gradedness were negatively correlated within both domains. Thus, confidence did indeed predict gradedness within the artifact and natural domains but failed to predict the difference in gradedness between those domains. There is more to gradedness than just uncertainty.     

Domain differences in the structure of artifactual and natural categories

In three experiments, different methodologies, measures, and items were employed to address the question of whether, and to what extent, membership in a semantic category is all or none (i.e., absolute) or a matter of degree (i.e., graded). Resemblance theory claims that categorization is based on similarity, and because similarity is graded, category membership may also be graded. Psychological essentialism asserts that categorization is based on the presumption of the category essence. Because artifactual (e.g., FURNITURE) and natural (e.g., FRUIT) categories have different sorts of essences, artifacts and natural kinds may be categorized in qualitatively different manners. The results converged onthe finding of a robust domain difference in category structure: Artifactual categories were more graded than natural categories. Furthermore, typicality reliably predicted absolute category membership, but failed to predict graded category membership. These results suggest that resemblance theory and psychological essentialism may provide a concerted account of representation and categorization across domains.     

Effect of theory-based feature correlations on typicality judgments

In the present study, we examine what types of feature correlations are salient in our conceptual representations. It was hypothesized that of all possible feature pairs, those that are explicitly recognized as correlated (i.e., explicit pairs) and affect typicality judgments are the ones that are more likely theory based than are those that are not explicitly recognized (i.e., implicit pairs). Real-world categories and their properties, taken from Malt and Smith (1984), were examined. We found that explicit pairs had a greater number of asymmetric dependency relations (i.e., one feature depends on the other feature, but not vice versa) and stronger dependency relations than did implicit pairs, which were statistically correlated in the environment but were not recognized as such. In addition, people more often provided specific relation labels for explicit pairs than for implicit pairs; these labels were most often causal relations. Finally, typicality judgments were more affected when explicit correlations were broken than when implicit correlations were broken. It is concluded that in natural categories, feature correlations that are explicitly represented and affect typicality judgments are the ones about which people have theories.     

A rule-based categorization deficit in Alzheimer's disease?

This study examined the categorization processes that Alzheimer's disease (AD) patients use during assessments of semantic memory. Rule-based categorization involves the careful, analytic processing of strict criteria to determine category membership, particularly for items from graded categories with ambiguous category membership; similarity-based categorization requires an overall comparison of a test stimulus with a prototype or remembered exemplar of the category and is relatively effective for the rapid categorization of items with unambiguous category membership. To assess these processes in AD, patients were asked to decide the category membership of test stimuli for categories with poorly defined or fuzzy boundaries (e.g., VEGETABLE) and for categories with well-defined boundaries (e.g., FEMALE) and then to judge the representativeness of the test stimulus for its chosen category. A subgroup of AD patients demonstrated a typical pattern of impaired semantic memory compared to healthy control subjects; that is, difficulty deciding the category membership of test items from fuzzy categories. Among these patients, we found no deficit in category membership decisions about items taken from well-defined categories. We also found that AD patients and healthy controls do not differ in their representativeness judgments of items within a correctly judged category. These findings are most consistent with the hypothesis that rule-based categorization difficulty limits semantic memory 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.     

Novel Labels Increase Category Coherence,But Only When People Have the Goal to Coordinate

From infancy, we recognize that labels denote category membership and help us to identify the critical features that objects within a category share. Labels not only reflect how we categorize, but also allow us to communicate and share categories with others. Given the special status of labels as markers of category membership, do novel labels (i.e., non‐words) affect the way in which adults select dimensions for categorization in unsupervised settings? Additionally, is the purpose of this effect primarily coordinative (i.e., do labels promote shared understanding of how we categorize objects)? To address this, we conducted two experiments in which participants individually categorized images of mountains with or without novel labels, and with or without a goal of coordination, within a non‐communicative paradigm. People who sorted items with novel labels had more similar categories than people who sorted without labels only when they were told that their categories should make sense to other people, and not otherwise. We argue that sorters' goals determine whether novel labels promote the development of socially coherent categories.     

Motions of the Hand Expose the Partial and Parallel Activation of Stereotypes

ABSTRACT— Perceivers spontaneously sort other people's faces into social categories and activate the stereotype knowledge associated with those categories. In the work described here, participants, presented with sex-typical and sex-atypical faces (i.e., faces containing a mixture of male and female features), identified which of two gender stereotypes (one masculine and one feminine) was appropriate for the face. Meanwhile, their hand movements were measured by recording the streaming x, y coordinates of the computer mouse. As participants stereotyped sex-atypical faces, real-time motor responses exhibited a continuous spatial attraction toward the opposite-gender stereotype. These data provide evidence for the partial and parallel activation of stereotypes belonging to alternate social categories. Thus, perceptual cues of the face can trigger a graded mixture of simultaneously active stereotype knowledge tied to alternate social categories, and this mixture settles over time onto ultimate judgments.     

Autonomous vs. comparative status: Must we be better than others to feel good about ourselves?

Previous research has shown that people's self-esteem and their group-oriented behavior are influenced by their judgments about the status of the groups to which they belong (pride) and assessments of their status within those groups (respect). These findings are important to justice researchers because the key antecedent of such status judgments is typically found to be the assessment of the fairness of group procedures (i.e., procedural justice). Research suggests that (1) procedural justice shapes status and that (2) status shapes self-esteem and group-oriented behavior. The paper reports the results of three studies comparing two different forms of these status judgments. The first form are autonomous judgments of pride and respect that are linked to the characteristics associated with membership in different groups. People link such judgments to inclusion or membership in the group. The second are comparative judgments of pride and respect that are linked to comparisons of one's status to the status of other people or groups. The results indicate that, within groups, people are influenced primarily by autonomous assessments of status based on their internal standards, which develop from the status associated with prototypical characteristics linked to inclusion in a group. People are less strongly influenced by comparisons of their status to the status of external comparison standards. Further, justice-based status inferences are shown to be primarily autonomous, and not comparative, in nature.     

Recollection-based prospective metamemory judgments are more accurate than those based on confidence: judgments of remembering and knowing (JORKS)

Five experiments were conducted to examine whether the nature of the information that is monitored during prospective metamemory judgments affected the relative accuracy of those judgments. We compared item-by-item judgments of learning (JOLs), which involved participants determining how confident they were that they would remember studied items, with judgments of remembering and knowing (JORKs), which involved participants determining whether studied items would later be accompanied by contextual details (i.e., remembering) or would not (i.e., knowing). JORKs were more accurate than JOLs when remember-know or confidence judgments were made at test and when cued recall was the outcome measure, but not for yes-no recognition. We conclude that the accuracy of metamemory judgments depends on the nature of the information monitored during study and test and that metamemory monitoring can be improved if participants are asked to base their judgments on contextual details rather than on confidence. These data support the contention that metamemory decisions can be based on qualitatively distinct cues, rather than an overall memory strength signal.     

Ad hoc categories

People construct ad hoc categories to achieve goals. For example, constructing the category of “things to sell at a garage sale” can be instrumental to achieving the goal of selling unwanted possessions. These categories differ from common categories (e.g., “fruit,” “furniture”) in that ad hoc categories violate the correlational structure of the environment and are not well established in memory. Regarding the latter property, the category concepts, concept-to-instance associations, and instance-to-concept associations structuring ad hoc categories are shown to be much less established in memory than those of common categories. Regardless of these differences, however, ad hoc categories possess graded structures (i.e., typicality gradients) as salient as those structuring common categories. This appears to be the result of a similarity comparison process that imposes graded structure on any category regardless of type.     

Speeded induction under uncertainty: The influence of multiple categories and feature conjunctions

When people are uncertain about the category membership of an item (e.g., Is it a dog or a dingo?), research shows that they tend to rely only on the dominant or most likely category when making inductions (e.g., How likely is it to befriend me?). An exception has been reported using speeded induction judgments where participants appeared to use information from multiple categories to make inductions (Verde, Murphy, &; Ross, 2005). In two speeded induction studies, we found that participants tended to rely on the frequency with which features co-occurred when making feature predictions, independently of category membership. This pattern held whether categories were considered implicitly (Experiment 1) or explicitly (Experiment 2) prior to feature induction. The results converge with other recent work suggesting that people often rely on feature conjunction information, rather than category boundaries, when making inductions under uncertainty.     

Essentialism and graded membership in animal and artifact categories

A number of studies have argued that people view membership in animal and artifact categories as a matter of degree. These studies have generally failed to distinguish between the issues of typicality and category membership. Thus, data which have been taken to demonstrate that membership is a matter of degree may only demonstrate that typicality is graded. Partly on the basis of these findings, it has been argued that some categories are organized around an underlying essence. The essence determines membership absolutely. The present paper reports a series of studies that reexamine the question of graded membership. In the first study, subjects were asked to rate both typicality and category membership for the same stimuli as a way of distinguishing the two questions. A second method relied on the intuition that disagreements about membership in all-or-none and graded categories may have different qualities. Results from both studies suggest some support for claims that membership in animai and artifact categories is a matter of degree. A third study explored the possibility that graded responses were due to conflicting, or ambiguous, sets of criteria. A task focusing on biological features did not lead to more absolute categorization. These results contradict essentialist predictions.     

Mood and the impact of individuating information on the evaluation of ingroup and outgroup members: The role of mood-based expectancies

This research investigates the role of mood-based expectancies regarding a target's group membership for the impact of individuating information on target judgments. We argue that target judgments in both positive and negative mood may be more or less affected by individuating information depending on whether the target is an ingroup member or an outgroup member. Specifically, in a competitive intergroup setting it should be less congruent with mood-based expectancies when individuals in positive (negative) mood learn that an outgroup (ingroup) member rather than an ingroup (outgroup) member has succeeded. Hence, unexpected (i.e., mood-incongruent) category information should elicit more attention than expected (mood-congruent) category information. More importantly, subsequent individuating information (high vs. low target competence) should be processed more effortful and influence target judgments more strongly given mood-incongruent (vs. mood-congruent) category membership. Findings of an experiment support these predictions. Results are discussed in regard to implications for different research domains.     

Essentialist to some degree: beliefs about the structure of natural kind categories

Previous research has provided conflicting evidence regarding the hypothesis that people are essentialists. Much of the evidence in favor of essentialism is based on demonstrating that categories are thought to have absolute membership. Although the hypothesis is often framed as an absolute claim about all categories of a certain type (e.g., natural kinds), it has generally been tested by making relative comparisons with a select sample. The present study assesses judgments of absolute structure across a range of categories. A further condition for essentialism is that the criteria for category identity be seen as objective rather than conventional. The results of three experiments based on these considerations do not provide support for essentialist claims. Few categories were judged to have essentialist structure, in terms of either absolute membership or objective criteria. Results are discussed in light of an alternative to the essentialist hypothesis that emphasizes a pragmatic view of categories.     

Examining differences in minority versus majority preschoolers on social categorization and perceived intergroup distance

We examined the differences between majority and minority children (i.e., group membership) on racial categorization and perceived cultural distance, among 4‐ to 6‐year‐old children, in low diversified schools. We used a spontaneous social categorization task using pictures of children from three different racial groups broadly represented in France (Europeans, Black‐, and North‐Africans), and an evaluation of the perceived cultural distance between participants' in‐group and the racial group represented in the picture, adapted to children and based on three factors (language, eating habits, and music). Results revealed an effect of age on racial categorization: the older the children, the more successful they are in this task. They showed a significant effect of the racial group represented in the photos on perceived cultural distance: members of minority groups (i.e., Black‐ and North‐Africans) were evaluated as more different compared to those of the majority group on each of the factors. Finally, we got an interaction between participants' in‐group and the racial group represented in the pictures, for the language factor: members of the majority group perceived as more different photographs representing minorities peers than those representing majority peers, while participants belonging to minority groups perceived no differences between photographs, according to the racial criteria.     

Size Does Matter: The Effects of Magnitude Representation Congruency on Price Perceptions and Purchase Likelihood

The numerical cognition literature suggests that numerical stimuli (and hence prices) are represented and encoded in memory as magnitude representations (i.e., judgments of relative “size”). The magnitude representation associated with the numerical value of a price may be the same as (congruent) or different from (incongruent) the magnitude representation associated with some other related dimension. We conducted 3 experiments to examine the effects of congruent versus incongruent magnitude representations on price perceptions and purchase intentions. We find that congruent magnitude representations result in more favorable price knowledge (i.e., greater value perceptions and lower price judgments) and increased purchase likelihood. Our findings suggest that consumers are not consciously aware of the role of magnitude representations in influencing price perceptions.     

On the signals underlying conscious awareness of action

To investigate whether conscious judgments of movement onset are based solely on pre-movement signals (i.e., premotor or efference copy signals) or whether sensory feedback (i.e., reafferent) signals also play a role, participants judged the onset of finger and toe movements that were either active (i.e., self initiated) or passive (i.e., initiated by the experimenter). Conscious judgments were made by reporting the position of a rotating clock hand presented on a computer screen and were then compared to the actual measured time of movement onset. In line with previous studies, judgment errors were found to be anticipatory for both finger and toe movements. There was a significant difference between judgment errors for active and passive movements, with judgments of active movements being more anticipatory than judgments of passive movements. This is consistent with a pre-movement (from here on referred to as an “efferent”) account of action awareness because premotor and efference copy signals are only present in active movements, whereas the main source of movement information in passive movements is sensory feedback which is subject to time delays of conduction (and hence predicts later judgment times for passive movements). However, judgments of active toe movement onset time were less anticipatory than judgments of active finger movement onset time. This pattern of results is not consistent with a pure efferent account of conscious awareness of action onset - as this account predicts more anticipatory judgments for toe movements compared to finger movements. Instead, the data support the idea that conscious judgments of movement onset are based on efferent (i.e., premotor, efference copy) and reafferent (i.e., feedback from the movement) components.     

Afraid of one afraid of all: When threat associations spread across face-types

Fear can be acquired for objects not inherently associated with threat (e.g. birds), and this threat may generalize from prototypical to peripheral category members (e.g. crows vs. penguins). When categorizing people, pervasive stereotypes link Black men to assumed violence and criminality. Faces with Afrocentric features (prototypical) are more often associated with threat and criminality than non-Afrocentric (peripheral) faces regardless of whether the individual is Black or White. In this study, using a priming paradigm, threat associations related to negative racial stereotypes were tested as a vehicle for spreading fear across face-type categories. Results showed more negative than positive judgments for White face targets but only when the prime was primarily non-Afrocentric (i.e. Eurocentric). Black face targets were judged more negatively than positively regardless of prime. This suggests some cognitive processes related to threat generalizations of objects extend to complex social categories.