Uncertainty in category-based induction: When do people integrate across categories?

Two experiments investigated how people perform category-based induction for items that have uncertain categorization. Whereas normative considerations suggest that people should consider multiple relevant categories, much past research has argued that people focus on only the most likely category. A new method is introduced in which responses on individual trials can be classified as using single or multiple categories, an improvement on past methods that relied on null effects as evidence for single-category use. Experiment 1 found that people did use multiple categories when the most likely category gave an ambiguous induction but that few people did so when it gave an unambiguous induction. Experiment 2 suggested that the reluctance to use multiple categories arose from a cognitive shortcut, in which only one source of information is consulted. The experiments revealed significant individual differences, suggesting that use of multiple categories is one of a number of strategies that can be used rather than being the basis for most category-based induction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Predicting features for members of natural categories when categorization is uncertain.

An important function of concepts is to allow the prediction of unseen features. A Bayesian account of feature prediction suggests that people will consider all the categories an object could belong to when they judge the likelihood that the object has a feature. The judgment and decision literature suggests that they may instead use a simpler heuristic in which they consider only the most likely category. In 3 experiments, no evidence was found that participants took into account alternative categories as well as the most likely one when they judged feature probabilities for familiar objects in meaningful contexts. These results, in conjunction with those of G. L. Murphy and B. H. Ross (1994), suggest that although people may consider alternative categories in certain limited situations, they often do not. Reasons for why the use of alternative categories may be relatively rare are discussed, and conditions under which people may take alternative categories into account are outlined. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Self-prediction: Exploring the parameters of accuracy.

Conducted 4 studies with 312 undergraduates to explore self-prediction processes of individuals. Study 1 examined the types of information people report using when making self-predictions. Five categories of information were determined. Studies 2 and 3 examined the relation between the use of different categories of information and self-perception accuracy. Results demonstrate the utility of attending to personal base rate and personal disposition information in formulating accurate self-predictions. Individual differences in accuracy as a function of public and private self-consciousness were also evident. Study 4 found that more certain self-predictions, as well as predictions that were distinct from what was expected for the average individual, were more accurate. Overall, findings suggest the importance of attending to individuating information in formulating accurate self-predictions. (70 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Category learning with minimal prior knowledge.

In 6 experiments, the authors examined the use of prior knowledge in category learning. Previous studies of the effects of knowledge on category learning have used categories in which knowledge was related to all of the category's features. However, people's knowledge of real-world categories often consists of many "rote" features that are not related to their prior knowledge. Five experiments found that even minimal prior knowledge (1 knowledge-relevant feature and 5 rote features per exemplar) can facilitate category learning. Posttests revealed that although the knowledge aided learning, subjects also acquired the rote features that were not related to knowledge, contradicting predictions of an attentional explanation of the knowledge effect. The results of Experiment 6 suggested that subjects attempt to link even rote features to their knowledge. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Prior knowledge and correlational structure in unsupervised learning.

Prior knowledge has been shown to facilitate both supervised and unsupervised category learning, but questions remain about how this facilitation occurs. This article describes two experiments that investigate the effects of prior knowledge on unsupervised learning, using the exemplar-memory task of Clapper and Bower (2002). Experiment 1 demonstrates that prior knowledge facilitates learning in this task, as expected, and that this facilitation extends to both knowledge-relevant and knowledge-irrelevant features of the new categories. Experiment 2 shows that knowledge facilitates learning not only by increasing the probability that people will discover separate categories, but also by making the features of different categories seem less interchangeable, thereby reducing interference and confusion among them. Taken together, these experiments demonstrate that prior knowledge has multiple effects on unsupervised learning and suggests that the exemplar-memory task may provide a useful procedure for disentangling and investigating these effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Once is enough: Causal reasoning from a single instance.

Points out that research on how people make predictions has focused on abstract rules and schemata. However, anecdotal evidence suggests that people often make predictions and explain events by comparing their situation to a single, previously experienced event. In 2 studies that examined this possibility, 161 undergraduates learned about members of a foreign culture, some of whom performed a rule-governed behavior. Ss then predicted the behavior of other members of the culture. One member was similar to an individual who performed the behavior, but the rule predicted that this new member would not perform the behavior. Both studies showed that in making their predictions, Ss relied on the similarity of this member to the previously encountered individual. Study 1 also demonstrated that people were increasingly likely to use a single, similar instance as the rule governing the behavior became more complex. Results emphasize the role that concrete experience plays in people's predictions. Further, they suggest that when people learn a novel behavior, they may, at least initially, learn a set of examples rather than a rule. (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Children's use of sample size and diversity information within basic-level categories

Category-based induction involves making decisions about some member(s) of a category based on information concerning other category members. Recent studies indicate that although adults make use of information concerning sample size (larger samples are a stronger basis of inference than smaller samples) and sample diversity (more diverse samples are better than more homogeneous samples) when making category-based inductive judgments, children do not do so until age 8 or 9 and even then to only a limited degree. This research however, was conducted at the superordinate level of categorization, and it is unclear if general difficulty with this category level may have masked children's ability to use size and diversity, or if these results represent a more entrenched conceptual difficulty in using this information. We therefore conducted three studies that investigate both 8- and 9-year-olds' and adults' ability to use sample size and diversity within basic level categories. Our results indicate that children's difficulty with this information is independent of category level, and may be based on preferences for other strategies concerning category membership and perceptual similarity.     

Setters and samoyeds: the emergence of subordinate level categories as a basis for inductive inference in preschool-age children

Basic level categories are a rich source of inductive inference for children and adults. These 3 experiments examine how preschool-age children partition their inductively rich basic level categories to form subordinate level categories and whether these have inductive potential. Children were taught a novel property about an individual member of a familiar basic level category (e.g., a collie). Then, children's extensions of that property to other objects from the same subordinate (e.g., other collies), basic (e.g., other dogs), and superordinate (e.g., other animals) level categories were examined. The results suggest (a) that contrastive information promotes the emergence of subordinate categories as a basis of inductive inference and (b) that newly established subordinate categories can retain their inductive potential in subsequent reasoning over a week's time.     

Category representations and the effects of interacting with instances.

People often classify new instances and then interact with or use them. Seven experiments showed that such interactions can affect the representation of the category. Equation categories, determined by both surface and mathematical properties, were used. In Experiments 1A and 1B, subjects solving the equations after classifying them were more likely to use the mathematical properties in later classifications than were subjects who had simply learned to classify. In Experiments 2A and 2B, different interactions led to very different classifications of test equations. Experiments 3–5 showed that such interactions affect category formation and graded structure, but do not lead to the solution group having worse memory for the surface contents. The discussion focuses on how these interactions may affect category representations and on the implications of this work for classification theories. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Conceptual distinctiveness supports detailed visual long-term memory for real-world objects.

Humans have a massive capacity to store detailed information in visual long-term memory. The present studies explored the fidelity of these visual long-term memory representations and examined how conceptual and perceptual features of object categories support this capacity. Observers viewed 2,800 object images with a different number of exemplars presented from each category. At test, observers indicated which of 2 exemplars they had previously studied. Memory performance was high and remained quite high (82% accuracy) with 16 exemplars from a category in memory, demonstrating a large memory capacity for object exemplars. However, memory performance decreased as more exemplars were held in memory, implying systematic categorical interference. Object categories with conceptually distinctive exemplars showed less interference in memory as the number of exemplars increased. Interference in memory was not predicted by the perceptual distinctiveness of exemplars from an object category, though these perceptual measures predicted visual search rates for an object target among exemplars. These data provide evidence that observers' capacity to remember visual information in long-term memory depends more on conceptual structure than perceptual distinctiveness. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Inference using categories.

How do people use category membership and similarity for making inductive inferences? The authors addressed this question by examining the impact of category labels and category features on inference and classification tasks that were designed to be comparable. In the inference task, participants predicted the value of a missing feature of an item given its category label and other feature values. In the classification task, participants predicted the category label of an item given its feature values. The results from 4 experiments suggest that category membership influences inference even when similarity information contradicts the category label. This tendency was stronger when the category label conveyed class inclusion information than when the label reflected a feature of the category. These findings suggest that category membership affects inference beyond similarity and that category labels and category features are 2 different things. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reactions to decisions with uncertain consequences: Reliance on perceived fairness versus predicted outcomes depends on knowledge.

Many decisions made by authorities pose uncertain consequences for the individuals affected by them, yet people must determine the extent to which they will support the change. Integrating the social justice and behavioral decision theory literatures, the article argues that individuals determine their support for proposed initiatives by assessing how knowledgeable they feel and using 2 main sources of information more or less heavily: their prediction of how the outcome of the initiative is likely to affect them or the perceived fairness of the decision maker. Three studies (2 experiments, 1 longitudinal field survey) assessing support for proposed public policies reveal that when individuals feel very knowledgeable they rely more on their prediction of how the outcome will affect them, whereas when they feel less knowledgeable they rely more on an overall impression of procedural fairness. The theoretical account and findings shed interdisciplinary insights into how people use process and outcome cues in reacting to decisions under uncertainty and ambiguity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Inference and Classification Learning of Abstract Coherent Categories.

Category learning research has primarily focused on how people learn to classify items using simple observable features. However, classification is only 1 way to learn categories. In addition, many concepts have an underlying coherence that explains the featural similarity among exemplars, such as abstract coherent concepts whose instances differ greatly on their observable features. In 3 experiments, the authors investigated how abstract coherent categories are acquired through 2 common means of category learning, classification and inference. Because inference promotes more focus on within-category information than does classification, they hypothesized that inference learning would lead to a better understanding of the underlying coherence of abstract coherent categories. All 3 experiments support this prediction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Inferring category attributes from exemplar attributes: Geometric shapes and social categories.

Three experiments tested the hypothesis that judgments about the attributes of categories are disproportionately based on the characteristics of exemplars that fit the category. In the first 2 experiments, subjects were presented with good and bad exemplars of categories with defining attributes (rectangles, triangles, pentagons, and ellipses) in which different colors were arbitrarily paired with the good and poor exemplars. In both experiments, subjects erroneously judged the colors paired with the good exemplars as more frequent than colors paired with the poor exemplars. A third experiment, using social categories, examined whether attributes associated with a single category member were more likely to generalize to the category as a whole for prototypical than for nonprototypical category members. Subjects were presented with information about individual fraternity members who varied in prototypicality, and the tendency to infer a target behavior (liberal vs. conservative voting behavior) from the individual fraternity member to the fraternity as a whole increased with the prototypicality of the category member. Implications for the contact hypothesis, category–exemplar relations, and belief stability are discussed. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

The relevance framework for category-based induction: Evidence from garden-path arguments.

Relevance theory (Sperber & Wilson, 1995) suggests that people expend cognitive effort when processing information in proportion to the cognitive effects to be gained from doing so. This theory has been used to explain how people apply their knowledge appropriately when evaluating category-based inductive arguments (Medin, Coley, Storms, & Hayes, 2003). In such arguments, people are told that a property is true of premise categories and are asked to evaluate the likelihood that it is also true of conclusion categories. According to the relevance framework, reasoners generate hypotheses about the relevant relation between the categories in the argument. We reasoned that premises inconsistent with early hypotheses about the relevant relation would have greater effects than consistent premises. We designed three premise garden-path arguments where the same 3rd premise was either consistent or inconsistent with likely hypotheses about the relevant relation. In Experiments 1 and 2, we showed that effort expended processing consistent premises (measured via reading times) was significantly less than effort expended on inconsistent premises. In Experiment 2 and 3, we demonstrated a direct relation between cognitive effect and cognitive effort. For garden-path arguments, belief change given inconsistent 3rd premises was significantly correlated with Premise 3 (Experiment 3) and conclusion (Experiments 2 and 3) reading times. For consistent arguments, the correlation between belief change and reading times did not approach significance. These results support the relevance framework for induction but are difficult to accommodate under other approaches. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The four elementary forms of sociality: Framework for a unified theory of social relations.

The motivation, planning, production, comprehension, coordination, and evaluation of human social life may be based largely on combinations of 4 psychological models. In communal sharing, people treat all members of a category as equivalent. In authority ranking, people attend to their positions in a linear ordering. In equality matching, people keep track of the imbalances among them. In market pricing, people orient to ratio values. Cultures use different rules to implement the 4 models. In addition to an array of inductive evidence from many cultures and approaches, the theory has been supported by ethnographic field work and 19 experimental studies using 7 different methods testing 6 different cognitive predictions on a wide range of Ss from 5 cultures. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Adult age differences in the perception and learning of artistic style categories.

Adult age differences in conceptual behavior were studied using informationally complex stimuli from real-world categories: paintings by two impressionist artists. In Experiment 1 we examined perceptions of category structure by having subjects sort paintings according to style similarity. Young adults were observed to depend more on abstract information in making style judgments, whereas older adults relied more on similarity in content. This resulted in different category structures between age groups, but similarity judgments in both groups appeared to correspond to actual style differences between the two artists. In Experiment 2, learning efficiency was shown to increase with a painting's category centrality, but older adults had particular trouble learning noncentral items. At transfer, both age groups were able to use abstracted central tendency information to categorize new paintings, although young adults appeared to have better access to information about specific category exemplars from acquisition. The results are generally consistent with those from studies using simpler artificial stimuli. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Accuracy and awareness in the perception and categorization of male sexual orientation.

For clear and unambiguous social categories, person perception occurs quite accurately from minimal cues. This article addresses the perception of an ambiguous social category (male sexual orientation) from minimal cues. Across 5 studies, the authors examined individuals' actual and self-assessed accuracy when judging male sexual orientation from faces and facial features. Although participants were able to make accurate judgments from multiple facial features (i.e., hair, the eyes, and the mouth area), their perceived accuracy was calibrated with their actual accuracy only when making judgments based on hairstyle, a controllable feature. These findings provide evidence that suggests different processes for extracting social category information during perception: explicit judgments based on obvious cues (hairstyle) and intuitive judgments based on nonobvious cues (information from the eyes and mouth area). Differences in the accuracy of judgments based on targets' controllability and perceivers' awareness of cues provides insight into the processes underlying intuitive predictions and intuitive judgments. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Object names and object functions serve as cues to categories for infants.

Can object names and functions act as cues to categories for infants? In Study 1, 14- and 18-month-old infants were shown novel category exemplars along with a function, a name, or no cues. Infants were then asked to "find another one," choosing between 2 novel objects (1 from the familiar category and the other not). Infants at both ages were more likely to select the category match in the function than in the no-cue condition. However, only at 18 months did naming the objects enhance categorization. Study 2 shows that names can facilitate categorization for 14-month-olds as well when a hint regarding the core meaning of the objects (the function of a single familiarization object) is provided. (PsycINFO Database Record (c) 2010 APA, all rights reserved)