The differing roles of comparison and contrast in children’s categorization

Comparison of perceptually similar exemplars from an object category encourages children to overlook compelling perceptual similarities and use relational and functional properties more relevant for taxonomic categorization. This article investigates whether showing children a contrasting object that is perceptually similar but out of kind serves the same function as comparison in heightening children’s attention to taxonomically relevant features. In this study, 4-year-olds completed a forced-choice categorization task in which they viewed exemplars from a target category and then selected among (a) a perceptually similar out-of-kind object, (b) a category member that differed perceptually from the exemplars, and (c) a thematically related object. Children were assigned to one of four conditions: No-Compare/No-Contrast, Compare/No-Contrast, No-Compare/Contrast, or Compare/Contrast. As in previous work, comparison increased the frequency of category responses, but there was no effect of contrast on categorization. However, only those in the Compare/Contrast condition displayed consistently taxonomic patterns of responding. Follow-up studies revealed that the effect of comparison plus contrast was evident only when comparison preceded, rather than followed, contrast information and that the value added by providing contrastive information is not attributable to the perceptual similarity between the category exemplars and the contrast object. Comparison and contrast make differing contributions to children’s categorization.     

Comparison in the Development of Categories

Recent research on children's word learning has led to a paradox. Although word learning appears to be a deep source of insight into conceptual knowledge for children, preschoolers often categorize objects on the basis of shallow perceptual features such as shape. The current studies seek to resolve this discrepancy. We suggest that comparing multiple instances of a category enables children to extract deeper relational commonalities among category members. We examine 4-year-olds' categorization behaviors when asked to select a match for a target object (e.g., an apple) between a perceptually similar, out-of-kind object (e.g., a balloon) and a perceptually different category match (e.g., a banana). Children who learn a novel word as a label for multiple instances of the category are more likely to select the category match over the perceptual match. Children who learn a label for only one instance are equally likely to select either alternative. This effect is present even when individual target instances are more perceptually similar to the perceptual choice than to the category choice. We conclude that structural alignment processes may be important in the development of category understanding.     

The effects of perceptual similarity and category membership on early word-referent identification

We investigated the impact of perceptual and categorical relatedness between a target and a distracter object on early referent identification in infants and adults. In an intermodal preferential looking (IPL) task, participants looked at a target object paired with a distracter object that could be perceptually similar or dissimilar and drawn from the same or different global category. The proportion of target looking measures revealed that infants and adults were sensitive to the interplay between category membership and perceptual similarity. Online latency measures demonstrated an advantage for perceptually dissimilar items regardless of their categorical status, indicating that different IPL measures index different processes during target identification. Results suggest that perceptual similarity and category membership of the objects lead to competition effects in word recognition and referent identification in both adults and infants and that lexical categorization and nonlinguistic categorization processes are closely related during infancy.     

Blinded by the accent! The minor role of looks in ethnic categorization

The categories that social targets belong to are often activated automatically. Most studies investigating social categorization have used visual stimuli or verbal labels, whereas ethnolinguistic identity theory posits that language is an essential dimension of ethnic identity. Language should therefore be used for social categorization. In 2 experiments, using the "Who Said What?" paradigm, the authors investigated social categorization by using accents (auditory stimuli) and looks (visual stimuli) to indicate ethnicity, either separately or in combination. Given either looks or accents only, the authors demonstrated that ethnic categorization can be based on accents, and the authors found a similar degree of ethnic categorization by accents and looks. When ethnic cues of looks and accents were combined by creating cross categories, there was a clear predominance of accents as meaningful cues for categorization, as shown in the respective parameters of a multinomial model. The present findings are discussed with regard to the generalizability of findings using one channel of presentation (e.g., visual) and the asymmetry found with different presentation channels for the category ethnicity.     

When Categorization Is Ambiguous: Factors That Facilitate the Use of a Multiple Category Inference Strategy

Prior research has established that categorization plays a central role in new product learning. Very little is known, however, about category‐based learning under conditions of categorization ambiguity. Of particular interest is whether and under what circumstances consumers might employ a multiple‐ (vs. single‐) category strategy to generate inferences about ambiguous products. In this research, we identified 2 factors—category familiarity and the nature of the category cue—that are responsible for determining whether inferences are based on a single category or multiple, competing categories. The results of 3 studies suggest that when an ambiguous product is described in terms of conflicting conceptual and perceptual category cues, a single category inference strategy is employed when the perceptually cued category is more familiar than the conceptually cued category. In particular, inferences are based largely on the perceptually cued category under these circumstances. However, when the perceptually cued category is less than or equal to the conceptually cued category in familiarity, a multiple category inference strategy is employed and inferences are based on both the perceptually and conceptually cued categories.     

Children's equivalence judgments: Crossmapping effects

Preschoolers made numerical comparisons between sets with varying degrees of shared surface similarity. When surface similarity was pitted against numerical equivalence (i.e., crossmapping), children made fewer number matches than when surface similarity was neutral (i.e, all sets contained the same objects). Only children who understood the number words for the target sets performed above chance in the crossmapping condition. These findings are consistent with previous research on children's non-numerical comparisons (e.g., [Rattermann, M. J., & Gentner, D. (1998). The effect of language on similarity: The use of relational labels improves young children's performance in a mapping task. In K. Holyoak, D. Gentner, & B. Kokinov (Eds.), Advances in analogy research: Integration of theory and data from cognitive, computational, and neural sciences (pp. 274–282). Sofia: New Bulgarian University; Smith, L. B. (1993). The concept of same. In H. W. Reese (Ed.), Advances in child development and behavior, Vol. 24 (pp. 215–252). New York: Academic Press]) and suggest that the same mechanisms may underlie numerical development.     

Masked translation priming asymmetry in Chinese-English bilinguals: Making sense of the Sense Model

Masked translation priming asymmetry is the robust finding that priming from a bilingual's first language (L1) to their second language (L2) is stronger than priming from L2 to L1. This asymmetry has been claimed to be task dependent. The Sense Model proposed by Finkbeiner, Forster, Nicol, and Nakamura (2004) claims that the asymmetry is reduced in semantic categorization relative to lexical decision due to a category filtering mechanism that limits the features considered in categorization decisions to dominant, category-relevant features. This paper reports two pairs of semantic categorization and lexical decision tasks designed to test the Sense Model's predictions. The experiments replicated the finding of Finkbeiner et al. that L2-L1 priming is somewhat stronger in semantic categorization than lexical decision, selectively for exemplars of the category. However, the direct comparison of L2-L1 and L1-L2 translation priming across tasks failed to confirm the Sense Model's central prediction that translation priming asymmetry is significantly reduced in semantic categorization. The data therefore fail to support the category filtering account of translation priming asymmetry. Rather, they suggest that pre-activation of conceptual features of the target category provides feedback to lexical forms that compensates for the weak connections between the lexical and conceptual representations of L2 words.     

Identification and categorization in visual search

Seven experiments were addressed to the general question of whether the identification of letters and numbers is a more rapid process than the categorization of such stimuli. Subjects were required to make a single response if a target stimulus specified by name (e.g., “A,” “2”) or designated by category class alone (e.g., “letter,” “number”) was presented in a trial. The principal findings were: (1) identification reaction times (RTs) were faster than categorization RTs: (2) RTs for targets shown without a context were faster than RTs for targets shown in the context of other stimuli; (3) identification RTs for targets shown in the context of stimuli from a different conceptual-taxonomic category were faster than RTs for targets shown in the context of stimuli from the same category only when target-context stimulus discriminability differencet were optimized. The results were interpreted in terms of a two-stage processing model in which context face,ors affect the duration of an initial encoding-scanning stage and search instruction (effective memory size) factors affect the duration of the memory comparison stage.     

相似和相同语言标签对幼儿归纳推理的影响

为进一步检验相似语言标签的效应,采用经典的三角属性归纳范式,通过两个实验研究了"相似/相同"的真实语言标签对4岁幼儿归纳推理的影响.在实验一中,三角范式中的三个刺激物属于同一类别,在实验二中,三个刺激物属于两种不同的类别.每个实验均有三种条件:在控制条件中,实验者用"这个"指代每个客体;在相似语言标签条件中,靶刺激与知觉不相似的比较刺激具有相同的、且暗示了类别成员关系的词素(例如,翠鸟—飞机—鸵鸟);在相同语言标签条件中,靶刺激和知觉不相似的比较刺激共享相同的语言标签(例如,鸟—飞机—鸟).结果一致显示,与控制条件相比,幼儿在相似语言标签条件下表现出了更多的基于概念的归纳,表明在真实语言标签条件下也存在相似语言标签效应.同时,研究结果也显示,幼儿在相似和相同语言标签条件下的归纳没有显著差异,说明语言标签在幼儿归纳中更可能传递了概念信息,从而挑战了Sloutsky等的理论.     

Carrot eaters or moving heads: inductive inference is better supported by salient features than by category labels

How do words affect generalization, and how do these effects change during development? One theory posits that even early in development, linguistic labels function as category markers and thus are different from the features of the stimuli they represent. Another theory holds that early in development, labels are akin to other features, but that they may become category markers in the course of development. We addressed this issue in two experiments with 4- to 5-year-olds and adults. In both experiments, participants performed a categorization task (in which they predicted a category label) and an induction task (in which they predicted a missing feature). In the latter task, the category label was pitted against a highly salient feature, such that reliance on the label and reliance on the salient feature would result in different patterns of responses. Results indicated that children relied on the salient feature when performing induction, whereas many adults relied on the category label. These results suggest that early in development, labels are no more than features, but that they may become category markers in the course of development.     

类别学习语言标签效应的眼动研究

采用眼动技术,通过两个实验探讨人工语言标签与真实语言标签在类别学习中的作用。实验一对33名大学本科被试施测,探讨了人工语言标签对类别学习的影响。结果发现,在人工语言标签下,个体会基于标签的相似性进行分类。实验二对34名大学本科被试施测,探讨了真实语言标签对类别学习的影响。结果发现,在真实语言标签下,个体会基于标签的类别知识进行分类。类别学习中语言标签效应的熟悉程度影响分类方式,不熟悉的类别语言标签基于相似性分类,熟悉的类别语言标签基于知识分类;基于类别知识分类准确性更高,速度更快。     

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.     

The role of linguistic labels in inductive generalization

What is the role of linguistic labels in inductive generalization? According to one approach labels denote categories and differ from object features, whereas according to another approach labels start out as features and may become category markers in the course of development. This issue was addressed in four experiments with 4- and 5-year-olds and adults. In Experiments 1 to 3, we replicated Yamauchi and Markman’s findings with adults (Journal of Memory and Language, 1998, Vol. 39, pp. 124–148, and Journal of Experimental Psychology: Learning, Memory, and Cognition, 2000, Vol. 26, pp. 776–795) and extended the paradigm to young children. In Experiment 4, we compared effects of labels with those of highly salient visual features. Overall, results of these experiments provide strong support for the idea that early in development labels function the same way as other features, but they may become category markers in the course of development. A related finding is that whereas categorization and induction may be different processes in adults, they seem to be equivalent in young children. These results are discussed with respect to theories of development of inductive generalization.     

Procedural learning in perceptual categorization

In two experiments, observers learned two types of category structures: those in which perfect accuracy could be achieved via some explicit rule-based strategy and those in which perfect accuracy required integrating information from separate perceptual dimensions at some predecisional stage. At the end of training, some observers were required to switch their hands on the response keys, whereas the assignment of categories to response keys was switched for other observers. With the rule-based category structures, neither change in response instructions interfered with categorization accuracy. However, with the information-integration structures, switching response key assignments interfered with categorization performance, but switching hands did not. These results are consistent with the hypothesis that abstract category labels are learned in rule-based categorization, whereas response positions are learned in information-integration categorization. The association to response positions also supports the hypothesis of a procedural-learning-based component to information integration categorization.     

Category ratio: A search for an optimal solution to reduce choice overload

This paper endeavors to find an optimal solution to alleviate the harmful consequences of choice overload using assortment categorization. Past research on assortment categorization has primarily studied the type of category labels. Only a few studies focused on the number of category labels, and the extant research is inconclusive on the right number of labels. This paper argues that the number of options under each label is more important in reducing choice overload than the number of labels. We call the number of options under each label “category ratio”. We integrate the research from four streams to recommend an optimal range of category ratio. In a field and a lab experiment, we tested the optimal category ratio as an intervention in the reduction of choice overload. The results of both experiments found a significant reduction in choice overload for the optimal category ratio. In experiment 3, we manipulated the category ratio to test whether the optimal category ratio is better than the non-optimal category ratio. The results of experiment 3 found that consumers experienced more satisfaction for the optimal category ratio than both uncategorized assortment and non-optimal category ratio. Past research has found that fewer labels and uninformative categorization are not helpful in the choice process. This paper finds that a few labels are beneficial only when the category ratio is within the proposed optimal range. Uninformative labels also reduced choice overload when categorized using the optimal category ratio.     

Language is not just for talking: redundant labels facilitate learning of novel categories

In addition to having communicative functions, verbal labels may play a role in shaping concepts. Two experiments assessed whether the presence of labels affected category formation. Subjects learned to categorize "aliens" as those to be approached or those to be avoided. After accuracy feedback on each response was provided, a nonsense label was either presented or not. Providing nonsense category labels facilitated category learning even though the labels were redundant and all subjects had equivalent experience with supervised categorization of the stimuli. A follow-up study investigated differences between learning verbal and nonverbal associations and showed that learning a nonverbal association did not facilitate categorization. The findings show that labels make category distinctions more concrete and bear directly on the language-and-thought debate.     

The Role of Phonetic Similarity and Orthographic Information in Asymmetrical Lexical Encoding in Second Language

This study examined two possible sources of asymmetrical lexical access: phonetic proximity to the nearest L1 category and orthographic information. Three groups of native Korean speakers learned Arabic non-words with sound pairs with/without an L1-dominant category (/l-r/ vs. /χ-?/), and then their phonetic categorization and lexical encoding abilities were evaluated. One group was presented with the same letters for the target pair (e.g.,?<l>?for both /l/ and /r/), the second group, different letters (e.g.,?<l>?for /l/,?<r>?for /r/), and the third group, auditory input only. The results of discrimination did not show any effect of these two sources, whereas in lexical encoding, (1) a pair with an L1-dominant category was more accurately encoded; and (2) orthographic information hindered the lexical encoding. In the following spelling recall task, the scores from the learners with different letters for the target pair were similar to a ceiling. Thus, orthographic information might help them to have target-like representation, despite difficulties in online processing.     

Discrimination and categorization of photographs of natural objects by chimpanzees (Pan troglodytes)

Two experiments assessed the ability of four adult female chimpanzees to categorize natural objects. Chimpanzees were initially trained to match different color photographs of familiar objects from four possible categories. In training, all the comparison stimuli were from the same category in one condition, and from different categories in another condition. For all subjects, training performance was consistently better for the "different category" than for the "same category" trials. Probe trials were shown after training. In probe trials, the sample and positive comparison stimuli were different items from the same category, and the foils were selected from among the three other test categories. Individual performance was above chance in probe trials, suggesting that categorization by chimpanzees may transcend perceptual resemblance. These results were later replicated with novel stimulus items from the same four categories (experiment 2). Altogether, this research demonstrates that chimpanzees grouped perceptually different exemplars within the same category, and further suggests that these animals formed conceptual representations of the categories. Accepted after revision: 10 August 2001 Electronic Publication     

Categorizing entities by common role

Many categories group together entities that play a common role across situations. For example, guest and host refer to complementary roles in visiting situations and, thus, are role-governed categories (A. B. Markman & Stilwell, Journal of Experiment & Theoretical Artificial Intelligence, 13, 329-358, 2001). However, categorizing an entity by role is one of many possible classification strategies. This article examines factors that promote role-governed categorization over thematic-relation-based categorization (Lin & Murphy, Journal of Experimental Psychology: General, 130, 3-28, 2001). In Experiments 1a and 1b, we demonstrate that the use of novel category labels facilitates role-governed categorization. In Experiments 2a and 2b, we demonstrate that analogical comparison facilitates role-governed categorization. In Experiments 1b and 2b, we show that these facilitatory factors induce a general sensitivity to role information, as opposed to only promoting role-governed categorization on an item-by-item basis.     

Associative and similarity-based processes in categorization decisions

Two experiments were directed at distinguishing associative and similarity-based accounts of systematic differences in categorization time for different items in natural categories. Experiment 1 investigated the correlation of categorization time with three measures of instance centrality in a category. Production frequency (PF), rated typicality, and familiarity from category norms for British participants (Hampton & Gardiner, 1983) were used to predict mean categorization times for 531 words in 12 semantic categories. PF and typicality (but not familiarity) were found to make significant and independent contributions to categorization time. Error rates were related only to typicality (apart from errors made to ambiguous or unknown items). Experiment 2 provided a further dissociation of PF and typicality. Manipulating the difficulty of the task through the relatedness of the false items interacted primarily with the effect of typicality on categorization time, whereas, under conditions of easy discrimination, prior exposure to the category exemplars affected only the contribution of PF to the decision time. The dissociation of typicality and PF measures is interpreted as providing evidence that speeded categorization involves both retrieval of associations indexed by PF and a similarity-based decision process indexed by typicality.