Stimulus recognizability judgments as a function of the utility of physical dimensions in recognition-discrimination problems

The effect of different Retraining conditions on the scaling of random forms for recognizability was examined. Pretraining conditions were defined by exposure to recognition-discrimination problems structured to emphasize or de-emphasize metron variability. Analyses of the results of the scaling task indicated that exposure to problems designed to emphasize metron variability within the “compactness” and “jaggedness” physical dimensions resulted in more extensive use of those dimensions, while no similar effect resulted from training with problems emphasizing an “x-axis areal asymmetry” physical dimension.     

The psychophysical dimensions of similarity among random shapes

Six psychological dimensions were recovered from similarity judgments of 20 random forms using Kruskal’s nonmetric scaling technique. These were related to 10 physical factors describing the forms by using canonical correlation analysis and rotations of the resulting vectors. Four factors accounted for 2/3 of the variance of the intersection of the physical and psychological spaces for each of 11 Ss. The factors are described as Complexity, Curvature, Curvature Dispersion, and Straight-length Dispers ion. The problem of the proper psychological distance metric is discussed, and individual differences among Ss are analyzed. The results lead to the conclusion that the four major factors found may be good representations of processes occurring in the perceptual system.     

The encoding of perceptual information in the organization of individual stimulus patterns

Two experiments compared the effectiveness of variable physical dimensions and relationships among the components of individual stimulus patterns as means for encoding perceptual information. Four different codes were constructed in which letters (A through P) were represented by redundant combinations of the shape and brightness of the four component forms in each stimulus pattern. Three of the codes differed in terms of the physical variables that were redundant, and a fourth code was designed to simplify the relationships within individual stimulus patterns. Ss were asked to identify each pattern by naming its letter label as rapidly as possible. Differences in the speed of identification between codes and between individual patterns within codes indicated that perceptual information was effectively encoded by the organization of relationships within individual stimulus patterns. The representation of stimulation in terms of relationships among components has several implications for models of human information processing.     

On cross-modal similarity: the perceptual structure of pitch, loudness, and brightness

Examined how pitch and loudness correspond to brightness. In the Experiment 1, 16 Ss identified which of 2 lights more resembled each of 16 tones; in Experiment 2, 8 of the same 16 Ss rated the similarity of lights to lights, tones to tones, and lights to tones. (1) Pitch and loudness both contributed to cross-modal similarity, but for most Ss pitch contributed more. (2) Individuals differed as to whether pitch or loudness contributed more; these differences were consistent across matching and similarity scaling. (3) Cross-modal similarity depended largely on relative stimulus values. (4) Multidimensional scaling revealed 2 perceptual dimensions, loudness and pitch, with brightness common to both. A simple quantitative model can describe the cross-modal comparisons, compatible with the view that perceptual similarity may be characterized through a malleable spatial representation that is multimodal as well as multidimensional.     

On the rate of acquisition of visual information about space,time, and intensity

The temporal course of acquisition of visual information was mapped by measuring the speed and accuracy With which Ss could discriminate the position, intensity, or duration of a stimulus that was varied independently on these three binary dimensions. The speed-accuracy tradeoff was different for each of the three discrimination tasks, with performance substantially superior in the position discrimination task. In the intensity and duration discrimination tasks, there were systematic changes with RT in the relative influences of the three stimulus variables over the two alternative responses, suggesting .three phases of the corresponding perceptual processes: an initial dominance by position of the stimulus, a subsequent, joint influence by both intensity and duration, and finally an exclusive control by the correct dimension. The results demonstrate that Ss can selectively attend to various dimensions of the same stimulus, with concommitantly varying time constants. The perceptual processes being tapped by a discrimination task depend upon instructions and upon RT.     

Dimensions of Stressful Situations: A Comparison Between a Response Analytical and a Stimulus Analytical Approach

The congruence between two different approaches for the isolation of situational dimensions was studied. For each of the two approaches, data were obtained from an inventory consisting of 24 stressful situations. In the first study (the response analytical approach), 77 youn male Ss rated the unpleasantness of each of the stressful situations. A principal components analysis was employed for the isolation of the situational factors. In the second study (the stimulus analytical approach), another 24 young male Ss rated the degree of experienced similarity of the same situations. A multidimensional scaling method was employed for the isolation of the situational dimensions. The factorial congruence between the two approaches was considerable.     

Relational properties and memory-based category construction.

Although many experiments have investigated factors that constrain perceptual category construction, there have been no investigations of factors that constrain memory-based (MB) category construction. Six experiments examined the extent to which perceptual and MB sorting were influenced by correlated dimensions, family resemblance principles, and conceptual knowledge. Sensitivity to many types of relational information (e.g., correlated features, causal relations, interactive properties of objects, and family resemblance relations) was observed with perceptual sorting, but these properties were rarely used to organize information in MB sorting conditions. Instead, there was a clear preference to organize categories around single dimensions. Even when perfectly correlated features were causally related, Ss in memory conditions did not use correlations to construct categories. The strengths and limitations of MB analyses and categorizations are discussed.     

Dissimilarities as indices of individual perceptual structure

The generality of dissimilarity judgments and of configurations obtained by multidimensional scaling (MDS) as indices of perceptual structure was examined. The Ss made magnitude estimates of dissimilarity of pairs of photos, and MDS configurations were constructed separately for each S. The compatability of dissimilarities (judgments or distances in MDS configurations) with two other tasks Ss performed was then examined. These additional tasks, an “encoding” and a “decoding” task, required the S to first construct a message by making use of a set of four photos and, a week later, to decode the messages. Results obtained were interpreted as indicating a degree of generality of the dissimilarities and supporting a hypothesis of individual differences in perceptual structure for the stimulus set. A “data-purification” hypothesis for MDS was discussed and examined.

     

Remembered odors and mental mixtures: tapping reservoirs of olfactory knowledge.

Five experiments explored how (a) perceived and remembered odor intensities relate to concentration; (b) odor intensities integrate in perceptual, memorial, and mentally constructed mixtures; and (c) components vary in intensity in physical versus mental mixtures. Ss estimated the magnitude of unmixed stimuli presented physically (perceptual estimation) or represented symbolically (memorial estimation). Ss also judged mixtures and their components in combinations of perceptual and memorial presentation. Power functions with similar exponents described the relations between both perceived and remembered intensity and concentration. Perceptual, memorial, and mental mixtures all followed much the same interactive rule of integration. Correspondingly, the intensities of components varied similarly in mentally constructed and physical mixtures. The results imply intensive invariance across odor perception and odor memory.     

Dimensional salience as a function of educational attainment and method of discrimination training

The effects of three methods of selective-attention training with 4-sided forms on the salience of an invagination physical dimension in discrimination judgments with a stimulus domain of 12-sided forms were examined for 6-year-old Ss of low and high educational attainment. The results demonstrated that training procedures involving perceptual demonstration or manipulation increase the invagination dimension salience in the 12-sided stimulus domain more than a verbal training procedure for low educational attainment Ss. Implications for the psychophysical study of relatedness of stimulus domains are discussed.     

The prioritization of perceptual processing in categorization

In three experiments, the effects of selective attention on perceptual processes in a complex multidimensional object categorization task were investigated. In each experiment, participants completed a perceptual-matching task to gain estimates of the perceptual salience of each stimulus dimension, then a categorization task using the same stimuli. In Experiments 1 and 2, the perceptual processing of stimulus dimensions was faster when dimensions were more diagnostic of category membership, regardless of their perceptual salience. Experiment 3 demonstrated that this prioritization of perceptual processing was evident even when stimuli were presented in unpredictable locations during categorization, indicating that the physical characteristics of the stimulus guide selective attention to diagnostic stimulus dimensions.     

The synthesis of length within and between perceptual systems

Two experiments are reported comparing the accuracy of Ss in making length combinations visually, haptically, and intersensorally. It was hypothesized that there would not be significant differences among the three conditions for perceptual combinations of length, because length is a highly familiar dimension that is capable of being cognitively organized. The hypothesis was supported, and the findings were related to other research comparing intra- and intersensory processes.     

Figural preference and the visual field

Three experiments tested a hypothesis that the shape and relative dimensions of the binocular visual field determine a preference for rectangles possessing dimensions similar to those of the golden section. The results were that Ss horizontally oriented the rectangles they had drawn in correspondence with the shape of the binocular visual field but when Ss chose the most pleasing rectangles there was no significant preference for rectangles whose long side was horizontal. For all experiments there was little preference for rectangles whose ratio of short to long side approximated the golden section. There was some evidence that the placement of the rectangles with respect to the background affects preference.     

Golden section: Preferred figural orientationI

A hypothesis that the shape of the binocular visual field determines the supposed preference for rectangles possessing dimensions similar to those of the golden section was tested by having Ss draw pleasing rectangles. The results indicated that rectangles were oriented in correspondence with the shape of the visual field but there was, generally, a failure to obtain ratios approximating the golden section.     

Golden section: Preferred figural orientation

A hypothesis that the shape of the binocular visual field determines the supposed preference for rectangles possessing dimensions similar to those of the golden section was tested by havltlg Ss draw pleasing rectangles. The results iudicated that rectangles were oriented in correspondence with the shape of the visual field but there was, generally, a failure to obtain ratios approximating the golden section.     

Attention and the measurement of perceptual learning

Novel and familiar letters were presented to Ss under conditions which controlled momentary attention states. The latencies of letter matching for the novel and familiar letters did not differ when Ss were expecting the particular letters which were presented. However, latencies to the two types of letters differed significantly when Ss were not expecting the particular letters which were presented. Additional exposures significantly reduced this difference, thereby generating a perceptual learning curve in terms of response latency. The main findings were interpreted in terms of a model of perceptual processing which involves mechanisms for hierarchical coding, selective attention, and automatic processing.     

Automatic vigilance: the attention-grabbing power of negative social information

One of the functions of automatic stimulus evaluation is to direct attention toward events that may have undesirable consequences for the perceiver's well-being. To test whether attentional resources are automatically directed away from an attended task to undesirable stimuli, Ss named the colors in which desirable and undesirable traits (e.g., honest, sadistic) appeared. Across 3 experiments, color-naming latencies were consistently longer for undesirable traits but did not differ within the desirable and undesirable categories. In Experiment 2, Ss also showed more incidental learning for undesirable traits, as predicted by the automatic vigilance (but not a perceptual defense) hypothesis. In Experiment 3, a diagnosticity (or base-rate) explanation of the vigilance effect was ruled out. The implications for deliberate processing in person perception and stereotyping are discussed.     

Consonant recognition with two levels of decision complexity

The perceptual tuning hypothesis can be expressed as a prediction that discrimination of a particular stimulus dimension will be enhanced if it is the only dimension requiring discrimination and not one of a set of dimensions in a multidimensional discrimination task. In previous tests of the tuning hypothesis, using speech material, the size of a message set has been manipulated as an indirect means of controlling the number of dimensions an observer is required to discriminate. In the present experiments the particular items appearing in a message set have been selected in order to control precisely the number of dimensions relevant to the discrimination task, and performance is estimated in terms of the discrimination of each relevant dimension. No evidence is found for a perceptual tuning effect even though it is argued that the conditions of the present experiment represent those most favourable for its elicitation.     

Predicting similarity and categorization from identification.

In this article, the relation between the identification, similarity judgment, and categorization of multidimensional perceptual stimuli is studied. The theoretical analysis focused on general recognition theory (GRT), which is a multidimensional generalization of signal detection theory. In one application, 2 Ss first identified a set of confusable stimuli and then made judgments of their pairwise similarity. The second application was to Nosofsky's (1985b, 1986) identification-categorization experiment. In both applications, a GRT model accounted for the identification data better than Luce's (1963) biased-choice model. The identification results were then used to predict performance in the similarity judgment and categorization conditions. The GRT identification model accurately predicted the similarity judgments under the assumption that Ss allocated attention to the 2 stimulus dimensions differently in the 2 tasks. The categorization data were predicted successfully without appealing to the notion of selective attention. Instead, a simpler GRT model that emphasized the different decision rules used in identification and categorization was adequate.     

Free sorting with stimuli clustered in a multidlmensional attribute space

An experiment was conducted to determine whether Ss leam, without knowledge of results or prior familiarization with the prototypes, to sort histoform stimuli generated by three probablistic rules into categories consistent with these mies. Seven Ss were asked to sort 30 stimuli (10 from each schema population) on each trial. No constraints were placed on the number of categories to be used. A statistic was developed to measure consistency between schema-defined categories and subjeet-defined categories. Four of the seven Ss met the leaming criterion, and demonstrated increasing consistency with the schema-defined categories across trials. In general, more categories than necessary were used to classify the stimuli correctly. The results raise several questions about classification strategies used by Ss in perceptual learning tasks with stimuli generated by probabilistic rules, and indicate the need for further research conceming the variables that influence perceptual category formation.