structure. Perceptual classification learning experiments were conducted in which presentation frequencies of individual exemplars were manipulated. The exemplars had varying degrees of similarity to members of the target and contrast categories. Classification accuracy and typicality ratings increased for exemplars presented with high frequency and for members of the target category that were similar to the high-frequency exemplars. Typicality decreased for members of the contrast category that were similar to the high-frequency exemplars. A frequency-sensitive similarity-to-exemplars model provided a good quantitative account of the classification learning and typicality data. The interactive relations among similarity, frequency, and categorization are considered in the General Discussion. Among the most well-established findings in the categorization literature is that categories have "graded structures"

Emotions are universally recognized from facial expressions—or so it has been claimed. To support that claim, research has been carried out in various modern cultures and in cultures relatively isolated from Western influence. A review of the methods used in that research raises questions of its ecological, convergent, and internal validity. Forced-choice response format, within-subject design, preselected photographs of posed facial expressions, and other features of method are each problematic. When they are altered, less supportive or nonsupportive results occur. When they are combined, these method factors may help to shape the results. Facial expressions and emotion labels are probably associated, but the association may vary with culture and is loose enough to be consistent with various alternative accounts, 8 of which are discussed. "Everyone knows that grief involves a gloomy and joy a cheerful countenance.... There are characteristic facial expressions which are observed to accompany anger, fear, erotic excitement, and all the other passions " (Aristotle, nd/1913, pp. 805, 808). Aristotle was not proposing a new idea but was cataloging what was known on the topic of physiognomy. The theory was that a person's physical appearance, especially in the face, reveals deeper characteristics: Poor proportions reveal a rogue, soft hair a coward, and a smile a happy person.' Today, few psychologists share Aristotle's belief about the meaning of poor proportions or soft hair, but many share his beliefs about facial expression and emotion. Oatley and Jenkins (1992) observed, "By far the most extensive body of data in the field of human emotions is that on facial expressions of emotion" (p. 67). Recent reviews of those data (see Table 1) agree that the face reveals emotion in a way that is universally understood: Happiness, surprise, fear, anger, contempt, disgust, and sadness—these seven emotions, plus or minus two, are recognized from facial expressions by all human beings, regardless of their cultural background.

this article should be addressed to R. Goldstone, Psychology Department, Indiana University, Bloomington, IN 47405 (e-mail: rgoldsto@ indiana.edu). Further information can be found at http://cognitrn.psych. indiana.edu/ Similarity in context ROBERT L. GOLDSTONE DOUGLAS L. MEDIN Northwestern University, Evanston, Illinois and JAMIN HALBERSTADT Similarity comparisons are highly sensitive to judgment context. Three experiments explore context effects that occur within a single comparison rather than across several trials. Experiment 1 shows reliable intransitivities in which a target is judged to be more similar to stimulus A than to stimulus B, more similar to B than to stimulus C, and more similar to C than to A. Experiment 2 explores the locus of Tversky's (1977) diagnosticity effect in which the relative similarity of two alternatives to a target is influenced by a third alternative. Experiment 3 demonstrates a new violation of choice independence which is explained by object dimensions' becoming foregrounded or backgrounded, depending upon the set of displayed objects. The observed violations of common assumptions to many models of similarity and choice can be accommodated in terms of a dynamic property-weighting process based on the variability and diagnosticity of dimensions

In unidimensional absolute identification tasks, participants identify stimuli that vary along a single dimension. Performance is surprisingly poor compared with discrimination of the same stimuli. Existing models assume that identification is achieved using long-term representations of absolute magnitudes. The authors propose an alternative relative judgment model (RJM) in which the elemental perceptual units are representations of the differences between current and previous stimuli. These differences are used, together with the previous feedback, to respond. Without using long-term representations of absolute magnitudes, the RJM accounts for (a) information transmission limits, (b) bowed serial position effects, and (c) sequential effects, where responses are biased toward immediately preceding stimuli but away from more distant stimuli (assimilation and contrast).

A memory-based scaling model—ANCHOR—is proposed and tested. The perceived magnitude of the target stimulus is compared with a set of anchors in memory. Anchor selection is probabilistic and sensitive to similarity, base-level strength, and recency. The winning anchor provides a reference point near the target and thereby converts the global scaling problem into a local comparison. An explicit correction strategy determines the final response. Two incremental learning mechanisms update the locations and base-level activations of the anchors. This gives rise to sequential, context, transfer, practice, and other dynamic effects. The scale unfolds as an adaptive map. A hierarchy of models is tested on a battery of quantitative measures from 2 experiments in absolute identification and category rating. Category rating is a widely used method of data collection in experimental psychology. Ratings come in a wide variety of guises: psychophysical scales, similarity judgments, typicality judgments, confidence ratings, attitude questionnaires, health selfreports, and many others. The participants in all these tasks are asked to rate things using an ordered set of categories such as 1,..., 7 or strongly agree,..., strongly disagree. Most people

How do human beings make wage comparisons? This paper provides empirical support for an approach suggested by the psychologist Allen Parducci. The paper combines an experimental study with an analysis of data on 16,000 British employees. Satisfaction levels are shown to depend not simply upon relative pay but upon an individual’s ordinal rank within a comparison group (for example, whether the individual is 4th or 34th in the wage hierarchy of the company). Moreover, consistent with Parducci’s theory, quits in a workplace are higher the greater is the positive skewness of the pay distribution. This research was supported by grants 88/S15050 from BBSRC (UK) and grants R000239002 and R000239351 from ESRC (UK). Any opinions in this article are those of the individual authors only; they do not necessarily reflect the views or policies of Watson Wyatt. For helpful suggestions, we are

Categorization research typically assumes that the cognitive system has access to a (more or less noisy) representation of the absolute magnitudes of the properties of stimuli and that this information is used in reaching a categorization decision. However, research on identification of simple perceptual stimuli suggests that people have very poor representations of absolute magnitude information and that judgments about absolute magnitude are strongly influenced by preceding material. The experiments presented here investigate such sequence effects in categorization tasks. Strong sequence effects were found. Classification of a borderline stimulus was more accurate when preceded by a distant member of

Category judgments of the average lengths of sets of lines were inconsistent with context-independent models of information integration: the effects of any particular line upon the judgment of average length varied inversely with the lengths of the other lines within the same set. This interaction, obtained in five separate experiments, was similar to that previously reported for auditory intensities. The judgments reflect two kinds of contextual effects: (a) withinset effects, in which the judgment of the set varies directly with the range of values within the set, and (b) between-set effects, in which the apparent interaction between the stimuli within a set depends upon the context provided by the different sets. A simple range model provides a method for separating the two types of contextual effects. The context between sets is postulated to affect only the response scale; when the responses are rescaled to allow for the between-set context, the integrated impression is dependent upon both the mean and the range of components within the set. The term "information integration"

Most supermarket categories are cluttered with items or SKUs (stock-keeping units) that differ very little at the attribute level. Previous research has found that reductions (up to 54%) in the number of low-selling SKUs need not affect perceptions of variety, and therefore sales, significantly. In this research, we analyze data from a natural experiment conducted by an online grocer in which 94% of the categories experienced dramatic cuts in the number of SKUs offered, particularly low-selling SKUs. We find sales were indeed affected dramatically, with sales increasing an average of 11% across the 42 categories examined. Sales rose in more than two-thirds of these categories, with nearly half experiencing an increase of 10% or more; 75% of households increased their overall expenditures after the cut in SKUs. In turn, we examined how different types of SKU reductions -- defined by how the cuts affect the available attributes or features of a category (e.g., the number of brands) -- af...

We explore the role of negative relationships in the context of social networks in work organizations. Though network researchers have emphasized the benefits and opportunities derived from positive interpersonal relationships, we examine the social liabilities that can result from negative relationships in order to flesh out the entire “social ledger. ” We define a negative relationship as an enduring, recurring set of negative judgments, feelings, and behavioral intentions towards another person – one person dislikes another. We identify the factors that lead to negative relationships in the workplace as well as factors that may moderate the relationship between negative relationships and individuals ’ task and socioemotional outcomes. We argue that these negative relationships may have greater power than positive relationships to explain workplace outcomes. We derive our argument from theory and research on negative asymmetry. Negative Relationships in Networks 3 “A man’s stature is determined by his enemies, not his friends. ”-- Al Pacino, City Hall Employees in organizations are embedded in social networks that can provide opportunities and benefits such as job attainment, job satisfaction, performance, salary, power, and promotions