Emotional response categorization.

Traditional theories of categorization in which categories are assumed to be grounded in perceptual similarity or theories ignore an important basis of conceptual structure: the emotion that a stimulus elicits in a perceiver. This article discusses the nature of, constraints on, and conditions of use of emotional response categories. Experiments in which participants sorted triads of concepts that shared both emotional and nonemotional relations indicate that individuals use emotional response categories when they are experiencing emotional states. Multidimensional scaling of similarity judgments by emotional and nonemotional perceivers supports a selective attention mechanism of these effects. Participants induced to feel happy or sad emotional states weighted the emotional responses associated with stimuli more heavily than people in relatively neutral states. The triad and multidimensional scaling findings, along with functional considerations, suggest that emotional response categorization is not only tenable, but necessary for a complete account of categorization. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sequence Effects in the Categorization of Tones Varying in Frequency.

In contrast to exemplar and decision-bound categorization models, the memory and contrast models described here do not assume that long-term representations of stimulus magnitudes are available. Instead, stimuli are assumed to be categorized using only their differences from a few recent stimuli. To test this alternative, the authors examined sequential effects in a binary categorization of 10 tones varying in frequency. Stimuli up to 2 trials back in the sequence had a significant effect on the response to the current stimulus. The effects of previous stimuli interacted with one another. A memory and contrast model, according to which only ordinal information about the differences between the current stimulus and recent preceding stimuli is used, best accounted for these data (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Extremely selective attention: Eye-tracking studies of the dynamic allocation of attention to stimulus features in categorization.

Humans have an extremely flexible ability to categorize regularities in their environment, in part because of attentional systems that allow them to focus on important perceptual information. In formal theories of categorization, attention is typically modeled with weights that selectively bias the processing of stimulus features. These theories make differing predictions about the degree of flexibility with which attention can be deployed in response to stimulus properties. Results from 2 eye-tracking studies show that humans can rapidly learn to differently allocate attention to members of different categories. These results provide the first unequivocal demonstration of stimulus-responsive attention in a categorization task. Furthermore, the authors found clear temporal patterns in the shifting of attention within trials that follow from the informativeness of particular stimulus features. These data provide new insights into the attention processes involved in categorization. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Categorization of sounds.

The authors conducted 4 experiments to test the decision-bound, prototype, and distribution theories for the categorization of sounds. They used as stimuli sounds varying in either resonance frequency or duration. They created different experimental conditions by varying the variance and overlap of 2 stimulus distributions used in a training phase and varying the size of the stimulus continuum used in the subsequent test phase. When resonance frequency was the stimulus dimension, the pattern of categorization-function slopes was in accordance with the decision-bound theory. When duration was the stimulus dimension, however, the slope pattern gave partial support for the decision-bound and distribution theories. The authors introduce a new categorization model combining aspects of decision-bound and distribution theories that gives a superior account of the slope patterns across the 2 stimulus dimensions. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Information-accumulation theory of speeded categorization.

A process model of perceptual categorization is presented, in which it is assumed that the earliest stages of categorization involve gradual accumulation of information about object features. The model provides a joint account of categorization choice proportions and response times by assuming that the probability that the information-accumulation process stops at a given time after stimulus presentation is a function of the stimulus information that has been acquired. The model provides an accurate account of categorization response times for integral-dimension stimuli and for separable-dimension stimuli, and it also explains effects of response deadlines and exemplar frequency. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Mechanism for Error Detection in Speeded Response Time Tasks.

The concept of error detection plays a central role in theories of executive control. In this article, the authors present a mechanism that can rapidly detect errors in speeded response time tasks. This error monitor assigns values to the output of cognitive processes involved in stimulus categorization and response generation and detects errors by identifying states of the system associated with negative value. The mechanism is formalized in a computational model based on a recent theoretical framework for understanding error processing in humans (C. B. Holroyd & M. G. H. Coles, 2002). The model is used to simulate behavioral and event-related brain potential data in a speeded response time task, and the results of the simulation are compared with empirical data. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Competition Between Antecedent and Between Subsequent Stimuli in Causal Judgments.

In the analysis of stimulus competition in causal judgment, 4 variables have been frequently confounded with respect to the conditions necessary for stimuli to compete: causal status of the competing stimuli (causes vs. effects), temporal order of the competing stimuli (antecedent vs. subsequent) relative to the noncompeting stimulus, directionality of training (predictive vs. diagnostic), and directionality of testing (predictive vs. diagnostic). In a factorial study using an overshadowing preparation, the authors isolated the role of each of these variables and their interactions. The results indicate that competition may be obtained in all conditions. Although some of the results are compatible with various theories of learning, the observation of stimulus competition in all conditions calls for a less restrictive reformulation of current learning theories that allows similar processing of antecedent and subsequent events, as well as of causes and effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of categorization, attribution, and encoding processes on leadership perceptions.

In this study we compared two cognitive processes that are often thought to precede leadership perceptions: causal attributions and categorization. This was done by experimentally manipulating factors relevant to attributions (consensus information) and categorization (stimulus prototypicality). Dependent measures were undergraduate subjects' perceptions of the leadership exhibited by stimulus people, shown on a 12-min videotape of a management group. The interaction of the leader prototypicality and consensus information factors on leadership perceptions was opposite to that predicted by attribution theory. The experimental evidence suggested that the interaction effect was based on subjects' categorization of stimuli in terms of leadership. A methodology developed to measure encoding of on-going leader behavior allowed tests of the social-information-processing sequence involved in forming leadership perceptions. Results support recent propositions of social-information-processing theory and demonstrated the usefulness of the encoding methodology. (57 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Apparatus Exposure Produces Profound Declines in Conditioned Nictitating-Membrane Responses to Discrete Conditioned Stimuli by the Rabbit (Oryctolagus cuniculus).

The present experiments demonstrated that in the rabbit (Oryctolagus cuniculus) nictitacing-membrane (NM) preparation, exposure to the experimental apparatus produces profound declines in conditioned responding to a discrete conditioned stimulus (CS; Experiments 1, 2A, and 3). Moreover, this decremental effect is at most attenuated in only a minor way when the unconditioned stimulus (US) is presented during exposure to the apparatus (Experiment 2B). Controls for retention loss (Experiments 1 and 3) and for handling and placement in a different context (Experiment 3) did not produce significant declines in responding. These findings challenge theories of extinction that rely primarily on context-US associations but are more consistent with theories that assume context-CS-US associations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Response-time tests of logical-rule models of categorization.

A recent resurgence in logical-rule theories of categorization has motivated the development of a class of models that predict not only choice probabilities but also categorization response times (RTs; Fifi?, Little, & Nosofsky, 2010). The new models combine mental-architecture and random-walk approaches within an integrated framework and predict detailed RT-distribution data at the level of individual participants and individual stimuli. To date, however, tests of the models have been limited to validation tests in which participants were provided with explicit instructions to adopt particular processing strategies for implementing the rules. In the present research, we test conditions in which categories are learned via induction over training exemplars and in which participants are free to adopt whatever classification strategy they choose. In addition, we explore how variations in stimulus formats, involving either spatially separated or overlapping dimensions, influence processing modes in rule-based classification tasks. In conditions involving spatially separated dimensions, strong evidence is obtained for application of logical-rule strategies operating in a serial-self-terminating processing mode. In conditions involving spatially overlapping dimensions, preliminary evidence is obtained that a mixture of serial and parallel processing underlies the application of rule-based classification strategies. The logical-rule models fare considerably better than major extant alternative models in accounting for the categorization RTs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Lexical effects on phonetic categorization: The role of stimulus naturalness and stimulus quality.

A series of experiments was conducted to determine whether the effects of lexical status on phonetic categorization were influenced by stimulus naturalness (replicating M. W. Burton, S. R. Baum, and S. E. Blumstein, 1989, who manipulated the intrinsic properties of the stimuli) and by stimulus quality (presenting the stimuli in white noise). The experiments compared continua varying in voice onset time (VOT) only to continua covarying VOT and amplitude of the burst and aspiration noise in no-noise and noise conditions. Results overall showed that the emergence of a lexical effect was influenced by stimulus quality but not by stimulus naturalness. Contrary to previous findings, significant lexical effects failed to emerge in the slower reaction time (RT) ranges. These results suggest that stimulus quality contributes to lexical effects on phonetic categorization, whereas stimulus naturalness does not. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of varied-stimulus exposure training on fear reduction and return of fear

The current investigation assessed the relative treatment benefits of persistence with one specific stimulus vs exposure to multiple versions of a stimulus. The study was a 2 (type of stimulus) x 3 (assessment occasion) design, in which two spider-fearful groups (N = 28) were compared across three different occasions: pre-treatment, post-treatment, and follow-up. Exposure trials were conducted with the same tarantula for participants in the control group, whereas experimental participants were exposed to four novel tarantulas. As predicted, the control group demonstrated significantly more habituation than the experimental group across exposure trials, yet showed a clear return of fear in response to a control spider at a 3-week follow-up assessment whereas the experimental group showed no increase in fear. These findings offer support for the beneficial effects of varying the stimulus during exposure, and challenge the reliance on indices of fear activation and habituation as accurate signals of the permanence of fear reduction.     

Decoupling object detection and categorization.

We investigated whether there exists a behavioral dependency between object detection and categorization. Previous work (Grill-Spector & Kanwisher, 2005) suggests that object detection and basic-level categorization may be the very same perceptual mechanism: As objects are parsed from the background they are categorized at the basic level. In the current study, we decouple object detection from categorization by manipulating the between-category contrast of the categorization decision. With a superordinate-level contrast with people as one of the target categories (e.g., cars vs. people), which replicates Grill-Spector and Kanwisher, we found that success at object detection depended on success at basic-level categorization and vice versa. But with a basic-level contrast (e.g., cars vs. boats) or superordinate-level contrast without people as a target category (e.g., dog vs. boat), success at object detection did not depend on success at basic-level categorization. Successful object detection could occur without successful basic-level categorization. Object detection and basic-level categorization do not seem to occur within the same early stage of visual processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A reply to Mace and Pittenger on "Directly perceiving Gibson".

A reply to Mace and Pittenger on "Directly Perceiving Gibson" (see record 2005-09162-001). W. M. Mace and J. B. Pittenger address themselves to a false issue when they argue that J. J. Gibson has both a theory of stimulus structure and a theory of attention. The point of the 1972 article by J. W. Gyr is that these two theories are not as well integrated as they might be or as integrated as Gibson intended them to be. Moreover, a point also stressed by Gyr and overlooked by Mace and Pittenger is that Gibson's findings of stimulus structure are also consistent with theories that are not theories of direct visual perception, and therefore such findings by themselves cannot be used to support Gibson's theory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dimensionality of disability labels.

Studied the perceptions of disabilities by using more comprehensive stimulus sets and a less constraining response mode. 73 respondents (mean age 38.24 yrs) sorted 35 disability labels on the basis of their similarity. The dimensionality of this large stimulus set was studied through the use of multidimensional scaling. A 4-dimensional solution accounting for 58% of the variance was retained. The dimensions were physical disabilities, behavioral-emotional vs cognitive disabilities, specific vs diffuse disabilities, and visibility. This comprehensive structure underlying perceptions of disabilities is discussed in relation to previous findings. (34 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Complex decision rules in categorization: Contrasting novice and experienced performance.

The ability of novice and experienced Ss to learn complex decision rules was tested with 3 categorization tasks. Each task involved 2 categories with exemplars that were normally distributed on 2 stimulus dimensions. Three separate sets of stimuli were used, and in each task the decision rule that maximized categorization accuracy was a highly nonlinear function of the stimulus dimension values. In the 3 tasks, all experienced Ss used highly nonlinear decision rules. Quadratic rules were supported over bilinear rules, and in many cases Ss used nearly optimal decision rules. These findings did not depend on whether the stimulus components were integral or separable. Novice Ss also did not use simple linear rules. A model that assumed Ss tried a succession of different linear rules was also rejected. Instead, novices appeared to use quadratic rules, although less consistently than experienced Ss. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparison and Contrast in Perceptual Categorization.

People categorized pairs of perceptual stimuli that varied in both category membership and pairwise similarity. Experiments 1 and 2 showed categorization of 1 color of a pair to be reliably contrasted from that of the other. This similarity-based contrast effect occurred only when the context stimulus was relevant for the categorization of the target (Experiment 3). The effect was not simply owing to perceptual color contrast (Experiment 4), and it extended to pictures from common semantic categories (Experiment 5). Results were consistent with a sign-and-magnitude version of N. Stewart and G. D. A. Brown's (2005) similarity-dissimilarity generalized context model, in which categorization is affected by both similarity to and difference from target categories. The data are also modeled with criterion setting theory (M. Treisman & T. C. Williams, 1984), in which the decision criterion is systematically shifted toward the mean of the current stimuli. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Error discounting in probabilistic category learning.

The assumption in some current theories of probabilistic categorization is that people gradually attenuate their learning in response to unavoidable error. However, existing evidence for this error discounting is sparse and open to alternative interpretations. We report 2 probabilistic–categorization experiments in which we investigated error discounting by shifting feedback probabilities to new values after different amounts of training. In both experiments, responding gradually became less responsive to errors, and learning was slowed for some time after the feedback shift. Both results were indicative of error discounting. Quantitative modeling of the data revealed that adding a mechanism for error discounting significantly improved the fits of an exemplar-based and a rule-based associative learning model, as well as of a recency-based model of categorization. We conclude that error discounting is an important component of probabilistic learning. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Similarity and discrimination: A selective review and a connectionist model.

The 1st part of this article evaluates the extent to which 2 elemental theories of conditioning, stimulus sampling theory and the R. A. Rescorla-A. R. Wagner (1972) theory, are able to account for the influence of similarity on discrimination learning. A number of findings are reviewed that are inconsistent with predictions derived from these theories, either in their present form or in various modified forms. The 2nd part of the article is concerned with developing an alternative, configural account for discrimination learning. In contrast to previous configural theories, the present version is set within the framework of a connectionist network. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Congruity effects evoked by subliminally presented primes: Automaticity rather than semantic processing.

In a size judgment task on words denoting concrete objects, subliminally presented stimuli that preceded the targets influenced response times and were dependent on whether responses to the prime and the target were congruent or incongruent (Experiment 1). These findings, mirroring S. Dehaene et al. (1998), imply that primes are unconsciously categorized and processed to the response stage. However, the effect does not generalize to primes that are not in the response set (Experiment 2), and even exposure to primes not in the response set in an interleaved naming-size judgment task fails to induce it (Experiment 3). However, the effect generalizes from lowercase primes to the same set of uppercase targets (Experiment 4), suggesting an abstract level of operation. The findings suggest that rather than resulting from unconscious prime categorization, the congruity effect results from automatized stimulus–response mappings. Potential differences between the number and the word domain are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)