Prototypes,exemplars, and the natural history of categorization

The article explores—from a utility/adaptation perspective—the role of prototype and exemplar processes in categorization. The author surveys important category tasks within the categorization literature from the perspective of the optimality of applying prototype and exemplar processes. Formal simulations reveal that organisms will often (not always!) receive more useful signals about category belongingness if they average their exemplar experience into a prototype and use this as the comparative standard for categorization. This survey then provides the theoretical context for considering the evolution of cognitive systems for categorization. In the article’s final sections, the author reviews recent research on the performance of nonhuman primates and humans in the tasks analyzed in the article. Diverse species share operating principles, default commitments, and processing weaknesses in categorization. From these commonalities, it may be possible to infer some properties of the categorization ecology these species generally experienced during cognitive evolution.     

The role of edge-based and surface-based information in natural scene categorization: Evidence from behavior and event-related potentials

A fundamental question in vision research is whether visual recognition is determined by edge-based information (e.g., edge, line, and conjunction) or surface-based information (e.g., color, brightness, and texture). To investigate this question, we manipulated the stimulus onset asynchrony (SOA) between the scene and the mask in a backward masking task of natural scene categorization. The behavioral results showed that correct classification was higher for line-drawings than for color photographs when the SOA was 13 ms, but lower when the SOA was longer. The ERP results revealed that most latencies of early components were shorter for the line-drawings than for the color photographs, and the latencies gradually increased with the SOA for the color photographs but not for the line-drawings. The results provide new evidence that edge-based information is the primary determinant of natural scene categorization, receiving priority processing; by contrast, surface information takes longer to facilitate natural scene categorization.     

Familiarity and categorization in intergroup behavior

Several studies have shown that social categorization into groups, unaffected by other variables such as own interest, interpersonal relations, conflict of interests, previous hostility, etc., was a sufficient condition to induce discrimination against an outgroup. The purpose of the present study was to test the hypothesis that the subjects' uncertainty and insecurity in a novel situation was, at least in part, responsible for this phenomenon. Two groups of subjects were tested: one group was made familiar with the social and physical setting of the experiment in a situation closely resembling the actual experiment, and came back for a second session in which the actual experiment was conducted; the second group came only for the actual experimental session. The results clearly indicate that, contrary to the hypothesis, the “familiar” group engaged in more out-group discrimination than the “unfamiliar” one. The theoretical and methodological implications of this finding are discussed.     

Negational categorization and intergroup behavior

Individuals define themselves, at times, as who they are (e.g., a psychologist) and, at other times, as who they are not (e.g., not an economist). Drawing on social identity, optimal distinctiveness, and balance theories, four studies examined the nature of negational identity relative to affirmational identity. One study explored the conditions that increase negational identification and found that activating the need for distinctiveness increased the accessibility of negational identities. Three additional studies revealed that negational categorization increased outgroup derogation relative to affirmational categorization and the authors argue that this effect is at least partially due to a focus on contrasting the self from the outgroup under negational categorization. Consistent with this argument, outgroup derogation following negational categorization was mitigated when connections to similar others were highlighted. By distinguishing negational identity from affirmational identity, a more complete picture of collective identity and intergroup behavior can start to emerge.     

Emotions,concepts and the indeterminacy of natural kinds

Synthese - A central question for philosophical psychology is which mental faculties form natural kinds. There is hot debate over the kind status of faculties as diverse as consciousness, seeing,...     

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.     

On the interactive influence of facial appearance and explicit knowledge in social categorization

Although people form impressions of others with ease, sometimes one's initial perceptions of individuals conflict with what one knows about them. Here, we aimed to investigate the process by which explicit knowledge about people interacts with initial perceptions on the basis of cues from facial appearance. Participants memorized the sexual orientations of men's faces wherein half of the targets were encoded with a sexual orientation opposite to their actual orientation. Subsequent categorization showed that perceivers favored appearance‐based information when temporally constrained but favored explicit knowledge about group membership with increased viewing time. Additionally, real‐time measures of participants' categorizations showed greater vacillation between appearance‐based cues and explicit knowledge as viewing time increased. These findings suggest that explicit knowledge does not simply overrule appearance‐based cues past a particular threshold but that the two may interact recurrently with top‐down knowledge directing attention and perception at later processing. Copyright © 2014 John Wiley & Sons, Ltd.     

Gender roles and the categorization of gender-relevant behavior

Biological sex has been assumed to be a basic category that importantly influences perceptions people have of others. However, it has recently been proposed that there are individual differences in this presumed generic propensity to use sex in person perception — that some people have schemas with regard to sex and gender, whereas others do not. Prior attempts to demonstrate these differences have frequently operationalized their variables in such a way that activation of hypothesized elaborate and dense gender schemas (schemas relating to psychological masculinity and femininity) could not be disentangled from activation of very shallow schemas related simply to biological sex or sex stereotypes. This study provides initial support for the conceptual distinction between cognitive processing based on biological sex vs. psychological gender. Independent manipulation of both sex-stereotyped information and less salient, nonstereotyped gender-relevant behavioral cues demonstrated that two levels of cognitive operation seem to be used. All subjects, regardless of gender role, used surface information regarding biological sex to make inferences regarding targets' masculinity and femininity. However, only some subjects made use of gender-related behavioral cues when assessing masculinity and femininity on indirect measures. Masculine males demonstrated their expertise in sex appropriateness in judging a male target who behaved sex appropriately, whereas cross-sex-typed subjects demonstrated expertise in sex inappropriateness in judgments of a male target who behaved sex inappropriately. The results are consistent with self-schema theory predictions regarding individual differences in schematic processing.An earlier report of this research was presented at the annual meeting of the American Psychological Association, New York, 1987, and additionally received Honorable Mention in the 1986 Association of Women in Psychology/APA Division 35 Student Research Competition. This research was supported by university funds to the second author, and was completed while the first author was at the University of California, Berkeley. The authors would like to thank Lauren Heim, Brad Elman, and Rosa Shen for their assistance with data collection and coding, and Sheri Matteo and two anonymous reviewers for their helpful comments on an earlier draft of this paper.     

Development and natural kinds

While philosophers tend to consider a single type of causal history, biologists distinguish between two kinds of causal history: evolutionary history and developmental history. This essay studies the peculiarity of development as a criterion for the individuation of biological traits and its relation to form, function, and evolution. By focusing on examples involving serial homologies and genetic reprogramming, we argue that morphology (form) and function, even when supplemented with evolutionary history, are sometimes insufficient to individuate traits. Developmental mechanisms bring in a novel aspect to the business of classification—identity of process-type—according to which entities are type-identical across individuals and natural kinds in virtue of the fact that they form and develop through similar processes. These considerations bear important metaphysical implications and have potential applications in several areas of philosophy.     

Supernatural beliefs,natural kinds,and conceptual structure

This article presents cross-cultural evidence in support of the notion that adults' natural kind concepts are theory based but may be informed by knowledge/belief systems other than the biological. Three groups of subjects from western Nigeria--rural, urban, and elite--participated in the study. Subjects heard stories describing alterations of appearance; that is, one natural kind was made to resemble another in both ritual and nonritual contexts. Subjects then were required to judge the identity of the altered item and to give an explanation for the category judgment. It was predicted that subjects would make more nonpreservation-of-identity category judgments supported by supernatural explanations in the ritual contexts and that subjects' use of supernatural explanations would reflect the extent of their engagement with the supernatural. The first prediction was borne out; the second prediction was only partially supported. Discussion of the results emphasizes the importance of exploring the role of sociocultural factors in conceptual structure.     

Development of categorization and reasoning in the natural world: novices to experts,naive similarity to ecological knowledge

Two experiments investigate the role of similarity and causal-ecological knowledge in expert and novice categorization and reasoning. In Experiment 1, university undergraduates and commercial fishermen sorted marine creatures into groups; although there was substantial agreement, novices sorted largely on the basis of appearance, whereas experts often cited commercial, ecological, or behavioral factors, and systematically subdivided fish on the basis of ecological niche. In Experiment 2, experts and novices were asked to generalize a blank property or novel disease from a pair of marine creatures. Novices relied on similarity to guide generalizations. Experts used similarity to reason about blank properties but ecological relations to reason about diseases. Expertise appears to involve knowledge of multiple relations among entities and context-sensitive application of those relations.     

Evidence for two kinds of low-typical instances in a categorization task

Three experiments examined the relationship between instance typicality and reaction time (RT) in a semantic categorization task. In all three experiments, first the instance was presented, and then the category. High-typicality high-imagery instances (e.g., robin) and lowtypicality low-imagery instances (e.g., grackle) were categorized faster than low-typicality highimagery instances (e.g., penguin). Instructing subjects to generate images of the instances had no influence on the pattern of results. The difference in categorization RT for lowimagery low-typicality instances vs. high-imagery high-typicality instances suggests that these instances may be represented differently in memory.     

Naming and categorization in young children: II. Listener behavior training

Following pretraining with everyday objects, 1- to 4-year-old children received listener training with three pairs of arbitrary stimuli of differing shapes. For each pair, 9 children were trained to select one stimulus in response to the spoken word /zog/ and the other to the spoken word /vek/. Next, in the look-at-sample category match-to-sample test, none categorized the six stimuli correctly when asked to look at the sample before selecting from five comparisons. Seven of these children failed a subsequent test of corresponding speaker behavior (tact test); following tact training, 5 of them passed either a repeat of the look-at-sample category test (2 subjects) or an alternative category test (3 subjects) in which they were required to tact the sample before selecting comparisons. The remaining 2 failed both category tests. Of the 2 who passed the tact test, 1 passed the tact-sample category test; the other failed to complete category testing. Two children were next given a second stimulus set. One passed the look-at-sample category test and the tact test; the other failed both tests but passed the tact-sample category test after tact training. The results show that 1- to 4-year-old children may learn listener behavior without corresponding speaker behavior. The results also show that common listener behavior is not sufficient to establish arbitrary stimulus classes, and they are consistent with the proposition that naming may be necessary for categorization of such stimuli.     

Revising the concept of lawhood: special sciences and natural kinds

The Kripkean conception of natural kinds (kinds are defined by essences that are intrinsic to their members and that lie at the microphysical level) indirectly finds support in a certain conception of a law of nature, according to which generalizations must have unlimited scope and be exceptionless to count as laws of nature. On my view, the kinds that constitute the subject matter of special sciences such as biology may very well turn out to be natural despite the fact that their essences fail to be microphysical or micro-based. On the causal conception of natural kinds I privilege, the naturalness of a kind is a function of the fact that it figures prominently in at least one causal law. However, there is a strong tendency prevailing among contemporary philosophers to assume that, in order to count as proper laws generalizations must be expectionless. Since most generalizations tracked down by the special sciences turn out not to fulfill these criteria, what this conception of a law implies is that most of the generalizations the special sciences trade in are not proper laws. It follows that, on this view, most if not all of the kinds the special sciences dealing with turn out not to constitute natural kinds, understood as kinds to which bona fide laws apply. In order to establish that the non-microstructurally defined kinds that fall within the domain of enquiry of the special sciences are eligible for the status of natural kind, I must therefore establish that generalizations needn’t have unlimited scope and be exceptionless to count as laws of nature. This is precisely what I seek to do in this paper. I begin by arguing that the question “what is a law of nature?” is most naturally interpreted as the question “what features must generalizations exhibit in order to ground scientific explanations?” and by offering reasons to believe that generalizations needn’t be exceptionless and have unlimited scope to play the crucial role laws have been thought to play in scientific explanation. Drawing on Sandra Mitchell [Mitchell, S. (2000). Philosophy of Science, 67, 242–265] and James Woodward’s [Woodward, J. (1997). Philosophy of science, 64 (proceedings), 524–541; Woodward, J. (2000). British Journal for the philosophy of science, 51(2), 197–254; Woodward, J. (2001). Philosophy of science, 68, 1–20] work, I subsequently develop an alternative account of the criteria generalizations must satisfy in order to count as laws of nature, which at least some of the generalizations of the special sciences turn out to fulfill. I thus give credence to the idea that at least some of the kinds that fall within the domain of the special sciences figure in laws of nature, and I thereby restore the possibility that some special science kinds deserve to be deemed natural.     

Effects of classification context on categorization in natural categories

The patterns of classification of borderline instances of eight common taxonomic categories were examined under three different instructional conditions to test two predictions: first, that lack of a specified context contributes to vagueness in categorization, and second, that altering the purpose of classification can lead to greater or lesser dependence on similarity in classification. The instructional conditions contrasted purely pragmatic with more technical/quasi-legal contexts as purposes for classification, and these were compared with a no-context control. The measures of category vagueness were between-subjects disagreement and within-subjects consistency, and the measures of similarity-based categorization were category breadth and the correlation of instance categorization probability with mean rated typicality, independently measured in a neutral context. Contrary to predictions, none of the measures of vagueness, reliability, category breadth, or correlation with typicality were generally affected by the instructional setting as a function of pragmatic versus technical purposes. Only one subcondition, in which a situational context was implied in addition to a purposive context, produced a significant change in categorization. Further experiments demonstrated that the effect of context was not increased when participants talked their way through the task, and that a technical context did not elicit more all-or-none categorization than did a pragmatic context. These findings place an important boundary condition on the effects of instructional context on conceptual categorization.