Categories and causality: the neglected direction

The standard approach guiding research on the relationship between categories and causality views categories as reflecting causal relations in the world. We provide evidence that the opposite direction also holds: categories that have been acquired in previous learning contexts may influence subsequent causal learning. In three experiments we show that identical causal learning input yields different attributions of causal capacity depending on the pre-existing categories to which the learning exemplars are assigned. There is a strong tendency to continue to use old conceptual schemes rather than switch to new ones even when the old categories are not optimal for predicting the new effect, and when they were motivated by goals that differed from the present context of causal discovery. However, we also found that the use of prior categories is dependent on the match between categories and causal effect. Whenever the category labels suggest natural kinds which can be plausibly related to the causal effects, transfer was observed. When the categories were arbitrary, or could not be plausibly related to the causal effect learners abandoned the categories, and used different categories to predict the causal effect.     

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.     

Psychological Essentialism of Human Categories

ABSTRACT— Psychological essentialism is an ordinary mode of category representation that has powerful social-psychological consequences. This article reviews those consequences, with a focus on the distinctive ways people perceive, evaluate, and interact with members of human categories they essentialize. Why and when people engage in this mode of thinking remain open questions. Variability in essentialism across cultures, categories, and contexts suggests that this mode of representing human categories is rooted in a naturalistic theory of category origins, combined with a need to explain differences that cross category boundaries.     

Causal knowledge and categories: the effects of causal beliefs on categorization, induction, and similarity

Despite the recent interest in the theoretical knowledge embedded in human representations of categories, little research has systematically manipulated the structure of such knowledge. Across four experiments this study assessed the effects of interattribute causal laws on a number of category-based judgments. The authors found that (a) any attribute occupying a central position in a network of causal relationships comes to dominate category membership, (b) combinations of attribute values are important to category membership to the extent they jointly confirm or violate the causal laws, and (c) the presence of causal knowledge affects the induction of new properties to the category. These effects were a result of the causal laws, rather than the empirical correlations produced by those laws. Implications for the doctrine of psychological essentialism, similarity-based models of categorization, and the representation of causal knowledge are discussed.     

Category coherence and category-based property induction

One important property of human object categories is that they define the sets of exemplars to which newly observed properties are generalized. We manipulated the causal knowledge associated with novel categories and assessed the resulting strength of property inductions. We found that the theoretical coherence afforded to a category by inter-feature causal relationships strengthened inductive projections. However, this effect depended on the degree to which the exemplar with the to-be-projected predicate manifested or satisfied its category's causal laws. That is, the coherence that supports inductive generalizations is a property of individual category members rather than categories. Moreover, we found that an exemplar's coherence was mediated by its degree of category membership. These results were obtained across a variety of causal network topologies and kinds of categories, including biological kinds, non-living natural kinds, and artifacts.     

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.     

Teleological Essentialism: Generalized

Natural/social kind essentialism is the view that natural kind categories, both living and non-living natural kinds, as well as social kinds (e.g., race, gender), are essentialized. On this view, artifactual kinds are not essentialized. Our view—teleological essentialism—is that a broad range of categories are essentialized in terms of teleology, including artifacts. Utilizing the same kinds of experiments typically used to provide evidence of essentialist thinking—involving superficial change (study 1), transformation of insides (study 2), and inferences about offspring (study 3)—we find support for the view that a broad range of categories—living natural kinds, non-living natural kinds, and artifactual kinds—are essentialized in terms of teleology. Study 4 tests a unique prediction of teleological essentialism and also provides evidence that people make inferences about purposes which in turn guide categorization judgments.     

The essentialist aspect of naive theories

Recent work on children's inferences concerning biological and chemical categories has suggested that children (and perhaps adults) are essentialists - a view known as psychological essentialism. I distinguish three varieties of psychological essentialism and investigate the ways in which essentialism explains the inferences for which it is supposed to account. Essentialism succeeds in explaining the inferences, I argue, because it attributes to the child belief in causal laws connecting category membership and the possession of certain characteristic appearances and behavior. This suggests that the data will be equally well explained by a non-essentialist hypothesis that attributes belief in the appropriate causal laws to the child, but makes no claim as to whether or not the child represents essences. I provide several reasons to think that this non-essentialist hypothesis is in fact superior to any version of the essentialist hypothesis.     

Psychological essentialism in children

Psychological essentialism is the idea that certain categories, such as "lion" or "female", have an underlying reality that cannot be observed directly. Where does this idea come from? This article reviews recent evidence suggesting that psychological essentialism is an early cognitive bias. Young children look beyond the obvious in many converging ways: when learning words, generalizing knowledge to new category members, reasoning about the insides of things, contemplating the role of nature versus nurture, and constructing causal explanations. These findings argue against the standard view of children as concrete thinkers, instead claiming that children have an early tendency to search for hidden, non-obvious features.     

Acquisition of basic object categories

Two implications of best-example theory for category acquisition were considered. The first is that categories which people acquire based on initial exposure to good exemplars should be learned more easily and (at first) more accurately than categories based on initial exposure to poor exemplars. The second is that people should generally learn that the best exemplars are category members, before learning that the poor exemplars are category members. These implications are based on the premise that people generalize based on similarity, and that the best example has maximal within-category similarity and minimal extra-category similarity, while the poor examples have minimal within-category similarity and relatively high extra-category similarity. Both implications were strongly supported by the present research. It was also found that when pressure to communicate was removed, comprehension and production of category names were virtually identical. The predictions of best-example theory concerning the conceptual structures underlying the words used by children who are just beginning to talk were discussed briefly. This research also allowed the replication of several important categorization results which had previously been found with real-world categories, with a set of artificial concrete object categories.     

What children infer from social categories

Children hold the belief that social categories have essences. We investigated what kinds of properties children feel licensed to infer about a person based on social category membership. Seventy-two 4-6-year-olds were introduced to novel social categories defined as having one internal - psychological or biological - and one external - behavioral or physical - property. For half of the participants, the internal property was described as causing the external one; for the others, no causal relationship between properties was mentioned. Children were asked to choose as a novel exemplar of a category one with only the internal or only the external property. Children inferred that exemplars had a psychological property irrespective of causal status, but they inferred the presence of a biological property only when described as causal. Children did not draw systematic inferences regarding either of the two external properties. These findings indicate that children treat psychological and causal properties as central - and perhaps essential - to human kinds.     

How does social essentialism affect the development of inter‐group relations?

Psychological essentialism is a pervasive conceptual bias to view categories as reflecting something deep, stable, and informative about their members. Scholars from diverse disciplines have long theorized that psychological essentialism has negative ramifications for inter‐group relations, yet little previous empirical work has experimentally tested the social implications of essentialist beliefs. Three studies (N = 127, ages 4.5–6) found that experimentally inducing essentialist beliefs about a novel social category led children to share fewer resources with category members, but did not lead to the out‐group dislike that defines social prejudice. These findings indicate that essentialism negatively influences some key components of inter‐group relations, but does not lead directly to the development of prejudice.     

How causal knowledge affects classification: A generative theory of categorization

Several theories have been proposed regarding how causal relations among features of objects affect how those objects are classified. The assumptions of these theories were tested in 3 experiments that manipulated the causal knowledge associated with novel categories. There were 3 results. The 1st was a multiple cause effect in which a feature's importance increases with its number of causes. The 2nd was a coherence effect in which good category members are those whose features jointly corroborate the category's causal knowledge. These 2 effects can be accounted for by assuming that good category members are those likely to be generated by a category's causal laws. The 3rd result was a primary cause effect, in which primary causes are more important to category membership. This effect can also be explained by a generative account with an additional assumption: that categories often are perceived to have hidden generative causes.     

“Internally Wicked”: Investigating How and Why Essentialism Influences Punitiveness and Moral Condemnation

Kant argued that individuals should be punished “proportional to their internal wickedness,” and recent work has demonstrated that essentialism—the notion that observable characteristics reflect internal, biological, unchanging “essences”—influences moral judgment. However, these efforts have yielded conflicting results: essentialism sometimes increases and sometimes decreases moral condemnation. To resolve these discrepancies, we investigated the mechanisms by which essentialism influences moral judgment, focusing on perceptions of actors’ control over their behavior, the target of essentialism (particular behaviors vs. actors’ character), and the component of essentialism (biology vs. immutability). Participants punished people described as having a criminal essence more than those with a non-criminal essence or no essence. Probing potential mechanisms underlying this effect, we found a mediating role for perceptions of control and weak influences of essentialism focus (behavior vs. character) and component of essentialism (biology vs. immutability). These results extend prior work on essentialism and moral cognition, demonstrating a causal link between perceptions of “internal wickedness” and moral judgment. Our findings also resolve discrepancies in past work on the influence of essentialism on moral judgment, highlighting the role that perceptions of actors’ control over their behavior play in moral condemnation.     

Category transfer in sequential causal learning: the unbroken mechanism hypothesis

The goal of the present set of studies is to explore the boundary conditions of category transfer in causal learning. Previous research has shown that people are capable of inducing categories based on causal learning input, and they often transfer these categories to new causal learning tasks. However, occasionally learners abandon the learned categories and induce new ones. Whereas previously it has been argued that transfer is only observed with essentialist categories in which the hidden properties are causally relevant for the target effect in the transfer relation, we here propose an alternative explanation, the unbroken mechanism hypothesis. This hypothesis claims that categories are transferred from a previously learned causal relation to a new causal relation when learners assume a causal mechanism linking the two relations that is continuous and unbroken. The findings of two causal learning experiments support the unbroken mechanism hypothesis.     

The lay distinction between primary and secondary emotions: A spontaneous categorization?

In line with the psychological essentialism perspective, Leyens et al. ( 13 2000) have hypothesized that people attribute different essences to groups and that they attribute more uniquely human characteristics to their own group than to out‐groups. Leyens et al. have focused on two types of emotions, which in Roman languages have specific labels, such as sentimientos and emociones in Spanish. A cross‐cultural study showed that sentimientos (or secondary emotions) are considered uniquely human emotions whereas emociones (or primary emotions) are perceived as nonuniquely human emotions. The present study focuses on whether this categorization into primary and secondary emotions is a spontaneous distinction that people use in their everyday lives, or whether, on the contrary, it is the result of experimental demands. The paradigm “Who says what to whom” was used to test this question. Geometrical shapes of different colours were systematically associated with different stimuli that varied in meaningfulness. In a first condition, shapes were associated with small or large items of furniture (meaningful categories) and with primary and secondary emotions. In a second condition, the items of furniture were replaced by words ending with a vowel or a consonant (meaningless categories). Subsequently, participants had to recognize which shape was associated with each stimulus. Intra‐category errors were significantly more numerous than inter‐category errors, except for the words ending with a vowel or a consonant. Stated otherwise, types of emotions were recognized like the meaningful difference between items of furniture. These results show that the distinction between primary and secondary emotions is an implicit one that people use spontaneously, and not as a result of task demands. The findings are discussed from the perspective of psychological essentialism and inter‐group relations.     

特征概率影响多维和少维类别的分类学习和特征学习

探讨了特征概率对多维和少维类别的分类学习和特征学习的效果及策略的影响。结果表明高特征概率条件下,多维比少维类别的分类学习更容易,而且学到更多的特征知识,多维条件下人们更倾向于整体性加工策略,而少维条件下人们倾向于分析性加工策略。低特征概率条件下,多维比少维类别的分类学习和特征学习都困难,且两种条件下人们都倾向于采取分析性加工策略。