Effects of background knowledge on category construction.

In category construction, participants are commonly asked to sort items into 2 groups. Although natural categories have a family resemblance (FamR) structure, participants rarely construct FamR categories in the sorting task. In previous research, participants constructed FamR categories when the features of the instances could be integrated into a coherent category, if the category theme was provided. In Experiments 1–4, participants constructed more FamR categories with thematic materials than with nonthematic materials, even without being cued with the theme. Experiments 5A and 5B showed that when instances contained conflicting features (i.e., features that are contradictory given background knowledge) participants were not more likely to construct FamR categories with the thematic materials, unless they had a way of discounting such features. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of category membership on comparative judgment.

The results of 4 experiments suggest that the role of categorization in comparative judgment is much greater than previously believed. Ss judged which of 2 objects, selected from 2 taxonomic categories, was larger. Items from one category were always larger than items from the other category. When the items in the pair were from different categories, the semantic distance effect was attenuated if the relation between the categories was also generally true in the real world. When the experimental relation between the 2 categories differed from that of the real world, no diminution of the magnitude of the distance effect was observed. Further experiments rule out an artifactual explanation and also establish that diminution of the distance effect will occur even if the correlation between category membership and magnitude is relatively modest. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of category length and strength on familiarity in recognition.

In most recognition models a decision is based on a global measure often termed familiarity. However, a response criterion is free to vary across lists varying in length and strength, making familiarity changes immeasurable. We presented a single list with a mixture of exemplars from many categories, so that the criterion would be unlikely to vary with length or strength of the category of the test item. False alarms rose with category length but not category strength, suggesting that familiarity does not change much with changes in strength of other items but grows when additional items are studied. The results were well fit by an extension of the search of associative memory (SAM) model presented by R. M. Shiffrin, R. Ratcliff, and S. E. Clark (see record 1990-13917-001). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Influence of prototypes on perceptions of prejudice.

Two studies examined the influence of cultural stereotypes and personal factors ( one's race, gender) on perceptions of racial and gender discrimination. Overall, the data suggest that our perceptions of prejudice are strongly influenced by specific expectations regarding who are the prototypic perpetrators and victims of prejudice. More general expectations regarding out-group conflict or regarding only the characteristics of the perpetrator appear to have less of an impact on such perceptions. Additionally, women were found to be more likely than men to perceive sexism directed against men and racism directed at African Americans and Caucasians. Also, African Americans were more likely than Caucasians to perceive racist events against Whites and Blacks. The implications of these data are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of experience and training on diagnostic accuracy.

In this reexamination of a previously published report (R. Brammer, 1997), psychologists and psychology students (N = 138) were provided an artificial intelligence program that simulated a clinical interview. The "client" provided paragraph-length answers to the questions participants chose to ask. At the end of their interview, the participants provided a brief diagnosis for the client. A path analysis revealed that clinical experience is a strong predictor of the ability to form an accurate diagnosis and that an individual's level of training, mediated by the number of diagnostic questions asked, also helps to derive accurate diagnoses. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of different leadership styles on group accuracy.

Manipulated variables of F. Fiedler's contingency model in a group problem-solving situation. Air Force cadets made private individual estimates of rank-order merit of survival items and subsequently were placed in 48 groups of 4-5 Ss to arrive at consensual estimates. A replication study conducted 1 yr. later utilized 32 new groups of 4-5 cadets. Leaders had been contacted earlier, given the solution, and told to assume specific roles: Type I (high accuracy, authoritarian); Type II (high accuracy, democratic); Type III (low accuracy, authoritarian); Type IV (low accuracy, democratic). Type I produced the highest accuracy, Types II and IV had intermediate and comparable accuracy, and Type III produced the lowest accuracy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparison-based learning: Effects of comparing instances during category learning.

When learning about a category, people often compare new instances with similar old instances and notice features common to the compared instances. Five experiments demonstrate that such comparisons cause features common to compared instances to be considered more important for the category than equally frequent features that are not common to compared instances. Exp 1 shows that what is learned depends on which instances are compared. Exp 2 investigates the conditions under which comparison-based learning occurs. The next experiments find that these comparisons affect subjective feature frequency (Exp 3) and sensitivity to feature correlations (Exp 4). Exp 5 shows that comparisons during early learning affect what is learned from later instances. The discussion focuses on the implications for models of category representation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of interpolated mugshot exposure on accuracy of eyewitness identification.

Four groups of 15 Ss (ages 20–65 yrs) observed a videotape of 3 men whom they were later asked to identify in a recognition test. Results demonstrate significant effects on confidence ratings of both target and nontarget stimuli through the interpolation of irrelevant face stimuli, but the pattern of results does not lend itself to a straightforward interpretation in terms of interference. (14 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Learning and memory for personality prototypes.

Examined whether personality traits, commonly assumed to be represented in memory as schemata, can be learned from observation. 116 undergraduates participating in 3 studies classified 60 person instances into group members and nonmembers as defined by the instances' match to a complex personality prototype. To simulate learning of fuzzy categories, each person instance provided conflicting cues to group membership. Learning for instances' group membership was excellent across studies. In Study 1, frequency of cues indicating group membership was overestimated among nongroup instances. In Study 2, schema-consistent memory bias was revealed for person instances. In Study 3, schemata of consistently positive memory bias was revealed for person instances. In Study 3, schemata of consistently positive (or negative) traits were learned faster than arbitrary schemata. Findings implicate the frequency sensitivity of memory of W. K. Estes (see record 1986-21175-001), and a model of probabilistic cued-memory retrieval is developed to account for the effects. Findings are discussed in relation to everyday cognitive performance. (50 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of frame-of-reference training on rater accuracy under alternative time delays.

Investigated the effects of frame-of-reference (FOR) training on various indexes of distance and correlational accuracy under alternative time delays. 150 Ss were assigned randomly to either FOR- or control- (i.e., minimal) training conditions, with 1 of 3 time delays: (1) no delay between training, observation, and rating; (2) ratings performed 2 days following training and ratee observations; or (3) ratee observations and ratings completed 2 days following training. Hypotheses were proposed predicting specific relationships between accuracy, recall memory, and learning, depending on the delay period. Overall, results support the categorization perspective on FOR-training effectiveness; however, different results were obtained depending on the type of accuracy index and time delay. The implications of these findings are discussed in terms of how they relate to the conceptual distinction between distance and correlational accuracy and to the role of on-line, memory-based, and inference-memory-based processing in the ratings of FOR trained raters. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Event category learning.

This research investigated the learning of event categories, in particular, categories of simple animated events, each involving a causal interaction between 2 characters. Four experiments examined whether correlations among attributes of events are easier to learn when they form part of a rich correlational structure than when they are independent of other correlations. Event attributes (e.g., state change, path of motion) were chosen to reflect distinctions made by verbs. Participants were presented with an unsupervised learning task and were then tested on whether the organization of correlations affected learning. Correlations forming part of a system of correlations were found to be better learned than isolated correlations. This finding of facilitation from correlational structure is explained in terms of a model that generates internal feedback to adjust the salience of attributes. These experiments also provide evidence regarding the role of object information in events, suggesting that this role is mediated by object category representations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of facial transformations on accuracy of recognition

Alterations of facial features between the initial phase of a memory task and a later recognition test lower identification accuracy. The effects of leaving on, leaving off, adding, or removing targets' eyeglasses or beards on identification accuracy were examined in two experiments with American undergraduates. The removal of eyeglasses and either type of beard transformation, especially the addition of a beard, lowered identification accuracy.     

Intuitive and empirical prototypes in childhood psychopathology.

This study examines the validity of intuitive classifications of experienced diagnosticians, that is, the empirical foundation of their intuitive prototypes. Intuitive prototypes of 10 experienced diagnosticians were collected in two tasks and were compared with the empirically based assessment system of T. M. Achenbach (T. M. Achenbach, K. C. Conners, H. C. Quay, F. C. Verhulst, & C. T. Howell, 1989). Results show that the intuitive prototypes correspond very poorly with the empirical core syndromes, instead consisting of different groups of symptoms from various core syndromes. The study also showed a low similarity between behaviors that clinicians judge as co- occurring with an incompletely specified syndrome and behaviors that empirically co-occur with that syndrome. Reasons for the difference between intuitive prototypes and empirically derived classification structures are discussed, as are consequences for diagnostic practice. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Inhibitory effects of drinker and nondrinker prototypes on adolescent alcohol consumption.

This prospective study examined the relation between 308 adolescents' images of typical drinkers and nondrinkers and their subsequent alcohol consumption. The results indicate that both images are associated with changes in consumption between ages 16 and 18 but that they operate in different ways. Contrary to previous assumptions, drinker images do not represent goal states for adolescents in that they are more negative than their self-images and nondrinker images and are not correlated with their ideal selves. In contrast, nondrinker images do appear to represent goal states for adolescents who abstain from drinking. Implications for intervention are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of examples and embedded questions on the accuracy of comprehension self-assessments.

This study extends research by Glenberg, Sanocki, Epstein, and Morris (1987) by suggesting that the accuracy of students' comprehension-monitoring self-assessments can be improved if they read expository text that contains illustrative examples and embedded questions. Students were asked to read text under different study conditions. It is argued that examples and embedded questions provide students with an opportunity to test their own level of understanding of passage content and, therefore, result in more accurate self-assessments of comprehension than does plain text. Students who read text with both examples and questions assessed their own comprehension more accurately than did students reading plain text. These students also made more accurate posttest predictions of test performance. It appears that active self-testing improves one's calibration of comprehension. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The intoxicated witness: Effects of alcohol on identification accuracy from showups.

The effect of alcohol on identification accuracy is potentially an important topic. This study examined the effects of alcohol consumption on identification accuracy from showups, the identification procedure most likely to be used by police with intoxicated witnesses. The blood alcohol level of people exposed to a target was measured. In the target-present showup condition, blood alcohol level was not significantly related to correct identification rate. In the target-absent showup condition, the higher the blood alcohol level, the more people were likely to make a false identification. Implications for law enforcement and future research directions are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Priming from category members on retrieval of other category members: Positive and negative effects.

In four experiments subjects retrieved exemplars of categories from short definitions. Definitions were preceded by primes that were other exemplars from the category, were neutral (asterisks), or were correct. Only positive priming from related primes was found for latency to retrieve the defined word correctly, and this was not a function of whether primes were ever correct. Some negative priming was found in error probabilities following different prime types, but errors were not more likely when the prime was closely related to the word to be retrieved, so negative priming was not due to spreading inhibition. The data were interpreted in terms of spreading activation theories, with positive priming from related words on latency to respond, correctly or incorrectly. When the response is incorrect, it may then be difficult to retrieve the correct response; this may account for the negative effects of semantically related primes reported by others. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceptions of the elderly: Stereotypes as prototypes.

Three studies examined the structure of young persons' perceptions of the elderly within the framework of E. Rosch's (1978) theory of natural categories; 189 undergraduates served as Ss. The 1st 2 studies employed picture-sorting, trait-rating, and statement-sorting tasks to demonstrate that the cognitive representation of the elderly as a social category was differentiated into meaningful subcategories associated with distinctive physical features and personality and behavioral characteristics. In addition, behavioral and personality associations were stronger for "prototypic" instances of the different subcategories than for less prototypic instances. The 3rd study investigated the effects of category prototypicality on the processing and recall of information about specific individuals. It was found that information that mixes features from different subcategories (within the general category of the elderly) was recalled less well than was homogeneous information. On the other hand, information describing an elderly individual that was inconsistent with generalized stereotypes of the aged took longer to process and was recalled as well as was prototype-consistent information. Results support the general conclusion that stereotyping of individuals occurs at the level of basic rather than superordinate categories. (16 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Prototypes in category learning: The effects of category size, category structure, and stimulus complexity.

Although research in categorization has sometimes been motivated by prototype theory, recent studies have favored exemplar theory. However, some of these studies focused on small, poorly differentiated categories composed of simple, 4-dimensional stimuli. Some analyzed the aggregate data of entire groups. Some compared powerful multiplicative exemplar models to less powerful additive prototype models. Here, comparable prototype and exemplar models were fit to individual-participant data in 4 experiments that sampled category sets varying in size, level of category structure, and stimulus complexity (dimensionality). The prototype model always fit the observed data better than the exemplar model did. Prototype-based processes seemed especially relevant when participants learned categories that were larger or contained more complex stimuli. (PsycINFO Database Record (c) 2010 APA, all rights reserved)