Pythagorean distance and the judged similarity of schematic stimuli

Independent groups of Ss rated the similarity of pairs of patterns belonging to the same class, either bef ore or af ter a discrimination task of schematic concept formation (SCF). Mean similarity increased as a function of SCF pretraining. A linear relationship was found between a Pythagorean distance measure on the patterns and subjective similarity of pairs of stimuli (r=.88). No such relationship was obtained from an analysis of judgments from a group that viewed random, nonschematic stimuli. A secondary analysis of the discrimination judgments in the SCF task showed that the Pythagorean distance measure was predictive of judgments on pairs of stimuli from the same schema family, but the relationship did not hold for pairs representing two different schemata. Multidimensional scaling analyses indicated that mildly deviant schematic stimuli were perceived to be instances of a single family. The dimensions describing a schema cluster appeared to be specific to the sample of stimuli. A tendency for the Kruskal procedures to collapse certain types of stimulus clusters was observed and discussed.     

Nonmetric scaling of line lengths using latencies,similarity, and same-different judgments

An experiment investigating the relation between various ways of deriving psychophysical functions for line length is reported. A two-phase computer-controlled experiment in which the stimuli were pairs of lines was performed. In the first phase, the pair was presented for several seconds and the S was required to make a category judgment of the similarity of the lines. In the second phase, the pair was presented for a very brief period of time and the S decided whether the lines were the same or of different lengths. Three sets of data were analyzed: (1) the similarity judgments, (2) the proportion of correct different judgments, and (3) the latency of the correct different judgments. An individual differences analysis indicated that there were individual differences in the similarity and latency data. This analysis was not applicable to the proportion data. Nonmetric scaling revealed that the psychophysical functions based on all three sets of data were essentially identical     

Functional classes and equivalence relations

Three adult subjects were taught a set of two-choice simultaneous discriminations, with three positive and three negative stimuli; all possible combinations of positive and negative stimuli yielded nine different pairs. The discriminations were repeatedly reversed and rereversed, the former positive stimuli becoming negative and the former negative stimuli becoming positive. With all subjects, a reversal of the contingencies for one pair of stimuli became sufficient to change their responses to all of the other pairs. The reversals had produced functional stimulus classes. Then, all subjects showed conditional discriminations emerging between members of a functional class; given a sample from one class and comparisons from both classes, they selected the comparison that was in the same class as the sample. Next, 2 of the subjects showed that the within-class conditional relations possessed the symmetric and transitive properties of equivalence relations; after having been taught to relate new stimuli to existing class members, the subjects then matched other class members to the new stimuli. Subsequent tests of two-choice discriminations showed that the conditional discriminations had transferred functional class membership to the new stimuli. The 3rd subject, who did not show equivalence relations among functional class members, was also found to have lost the within-class conditional relations after the equivalence tests.     

The relation between proximity and brightness similarity in dot patterns

The Gestalt studies demonstrated the tendency to visually organize dots on the basis of similarity, proximity, and global properties such as closure, good continuation, and symmetry. The particular organization imposed on a collection of dots is thus determined by many factors, some local, some global. We discuss computational reasons for expecting the initial stages of grouping to be achieved by processes with purely local support. In the case of dot patterns, the expectation is that neighboring dots are grouped as a function of proximity and similarity of contrast, by processes that are independent of the overall organization and the various global factors. We describe experiments that suggest a purely local relationship between proximity and brightness similarity in perceptual grouping.     

Feature encoding and pattern classifications with sequentially presented Markov stimuli

The major objective of this experiment was to develop and evaluate a methodology designed to permit more direct assessment of the detailed processes involved in prototype abstraction. Thirty Ss participated in a task having the following characteristics: (1) classifications of Markov-generated stimuli sampled from two different populations, (2) controlled scanning of pattern features, (3) a measure of the degree to which pattern features were correctly identified, and (4) intermittent reproduction of pattern features abstracted from collections of mixed instances. Results showed that a significant number of the Ss learned to classify the stimuli into categories corresponding to generation rules and, at least partially, abstracted the population prototypes from these variable instances. The feature identification data suggested that the Ss who were unsuccessful in classifying the stimuli into the rule-defined categories used an inappropriate strategy for sampling pattern information upon which to base their classifications.     

Transfer of calibration between hand and foot: Functional equivalence and fractal fluctuations

Transfer of competency in a perceptual task often depends on shared information between anatomically different perceptual subsystems. The problem of studying transfer involves isolating conditions of similarity and then trying to account for any resulting differences in transfer. To respect this twofold aspect, this article takes a two-pronged approach to transfer in dynamic touch. The present research first tests the hypothesis that functional equivalence supports the transfer of dynamic touch. Participants were trained to wield unseen objects with the hand or foot and were then tested on anatomically disparate limbs (i.e., the foot or hand, respectively). Next, we examined motion capture of these wielding behaviors for predictors of any asymmetry in transfer. Temporally fractal fluctuations of exploratory behavior can modulate information detection, and we tested whether the fractality of wielding might predict asymmetries in transfer across disparate limbs. Results suggest that transfer of training to anatomically disparate limbs respects functional conditions of similarity and also that the degree of temporally fractal fluctuations predicted limb differences in transfer.     

Importance of the overall similarity of objects of adults' and children's classifications

Previous work has shown that adults and older children tend to classify multi-dimensional objects by identity on one dimension, whereas children under 8 years of age tend to classify these same objects by a relation of overall similarity. The present study investigated the hypothesis that this developmental trend is restricted to the classification of simple objects that differ only by limited amounts on a few dimensions. The specific hypothesis was that overall-similarity relations structure both adults' and children's classifications of heterogenous objects (objects that differ in a variety of ways). This hypothesis was suggested by the correspondence between the structure of young children's classifications and the structure of natural categories. The result of two experiments supported the hypothesis. When the to-be-classified objects varied simultaneously on relatively many dimensions, adults as well as children constructed classifications that maximized within-category similarity on all varying dimensions. The implications of these results for accounts of the perception of multidimensional relations and classificatory behavior are discussed.     

Changes in same-different laterality patterns as a function of practice and stimulus quality

Accuracy and reaction time (RT) of judgments about sameness vs. difference of (a) names of two letters and (b) shapes of two nonverbal forms were examined for stimuli presented to the center, left (LVF), and right (RVF) visual fields. For same-name letter pairs during Experiment I, responses were more accurate and faster for LVF than for RVF trials on an initial 90-trial block, but this difference was reversed by a third 90-trial block. The RVF advantage for RT was maintained over Trial Blocks 4 and 5, given during a second session, but had disappeared on Trial Blocks 6 through 9 as RT reached the same asymptotic level for both visual fields. No LVF-RVF differences were obtained at any level of practice for different-name letter pairs or for any of the form pairs. Experiment II replicated the shift from LVF toward RVF advantage that occurred over the first three trial blocks of Experiment I and demonstrated that such a shift does not occur when the letters are perceptually degraded. The results were discussed in terms of differences in cerebral hemisphere specialization for visuospatial vs. abstract stages of letter processing and changes with practice in the relative difficulty of these stages.     

Functional similarity and interpersonal attraction

A pair of related experiments examined the relationship of functional similarity (i.e., the degree of similarity between two interactants in assessing mutually known others on personal construct dimensions) to interpersonal attraction. In Experiment I, 10 previously unacquainted college students of both sexes participated in 10 hours of dyadic disclosure exercises over a 5-week period. As predicted, members of high functional similarity dyads evidenced greater attraction to one another than did members of low functional similarity dyads. Experiment II investigated the relationship of functional similarity to level of acquaintance (i.e., friends, nominals) and type of assessment (i.e., physical, interactional, psychological) in a 2 × 3 factorial design. As hypothesized, “friendship” pairs of male undergraduates displayed greater functional similarity than did “nominal” pairs from the same population, particularly at the deeper level of “psychological” assessment. Results are discussed in relation to classical conditioning (D. Byrne, In L. Berkowitz (Ed.), Advances in experimental social psychology, Vol. 4. New York. Academic Press, 1969), affect-reinforcement (G. L. Clore, In S. W. Duck (Ed.), Theory and practice in interpersonal attraction. New York/London: Academic Press, 1977) and information processing ( I. Ajzen, In S. Duck (Ed.), Theory and practice in interpersonal attraction, New York/London: Academic Press, 1977) models of interpersonal attraction, and are interpreted as supporting and extending (S. Duck's Theory and practice in interpersonal attraction, New York/London: Academic Press, 1977) filtering theory of friendship formation.     

Perceptual sensitivity to dimensional and similarity relations in free and rule-governed classifications

Two experiments were conducted to investigate the perceptual primacy of dimensional and similarity relations in the stimulus classifications of younger and older subjects. In Experiment 1, 4- and 10-year-olds were given free classifications in which they could group stimuli according to overall similarity or identities in size, color, or orientation. Both age groups classified stimuli most frequently according to identities on separate dimensions. In Experiment 2, 4-year-olds and adults were given free classifications followed by rule-governed classifications which required them to group stimuli according to specific relations. In the free classifications, a majority of subjects in both age groups classified the stimuli most frequently according to identities on separate dimensions. In the rule-governed classifications, both age groups were more accurate when a single separate relation was required for solution than when overall similarity was required. These results support a differential-sensitivity view of perceptual development, which asserts that individuals at all ages primarily perceive and use separate relations.     

A multidimensional scaling analysis of judged similarity of complex forms from two task situations

Ss provided judgments of pairwise stimulus similarities for 21 12-turn random forms in two experimental tasks: a scaling task, involving a variant of the method of graded dichotomies, and a sorting task, which simply required Ss to categorize the forms. The grouped data from both tasks, when analyzed using nonmetric multidimensional scaling techniques, yielded five-dimensional configurations with euclidean distances. The correspondence of these two spaces, assessed using canonical correlations, was extremely good. The psychological dimensions derived from both tasks were related to two sets of physical measures on the forms: the factor space suggested by Brown and Owen and a set of more basic physical measures. Physical cues of greatest importance involved size, dispersion, angularity, and rotation measures. The value of the tasks and the utility of the Brown and Owen measures were discussed.     

Evidence for a distinction between judged and perceived causality

Two experiments investigated Michotte's launch event, in which successive motion of two objects appears to evoke an immediate perception that the first motion caused the second, as in a collision. Launching was embedded in event sequences where a third event (a colour change of the second object) was established as a competing predictor of the second motion, in an attempt to see whether subjects' learning of alternative predictive relationships would influence their causal impressions of launch events. In Experiment 1 subjects saw launch events in which temporal contiguity at the point of impact was varied so that an impact was varied so that an impact itself did not reliably predict when the second object would move. Half of these scenes, however, contained a colour change of the second object which did reliably predict when it would move. In accordance with Michotte's theory, subjects' ratings of the degree of perceived causality were not affected by the colour change. In Experiment 2 subjects saw scenes that contained launch events with or without temporal contiguity and a colour change. These were interspersed with events in which a colour change alone did or did not precede the second motion. Thus, movement of the second object was either contingent on or independent of the impact. Subjects repeatedly (a) rated perceived causality in single launch events and (b) judged the necessity of collisions for movement in the overall set of events. These responses dissociated, in that ratings type (a) showed only a substantial contiguity effect, whereas judgements of type (b) showed both a contingency and a much smaller contiguity effect. These results appear to support a distinction between judged and perceived causality and are discussed with respect to Michotte's theory of direct causal perception.     

The generality of the relation between familiarity and judged validity

Using factual information of uncertain truth value as the stimulus material, previous investigators have found that repeated statements are rated more valid than non-repeated statements. Experiments 1 and 1A were designed to determine if this effect would also occur for opinion statements and for statements initially rated either true or false. Subjects were exposed to a 108-statement list one week and a second list of the same length a week later. This second list was comprised of some of the statements seen earlier plus some statements seen for the first time. Results suggested that all types of repeated statements are rated as more valid than their non-repeated counterparts. Experiment 2 demonstrated that the validity-enhancing effect of repetition does not occur in subject domains about which a person claims not be knowledgeable. From the results of both studies we concluded that familiarity is a basis for the judged validity of statements. The relation between this phenomenon and the judged validity of decisions and predictions was also discussed.     

Effects of test-mask similarity on forward and backward masking of patterns by patterns

Summary Effects of test-mask similarity on the masking function were examined in two experiments. In Experiment 1, random bar patterns were used as test and mask stimuli. Bars were oriented in 135° oblique direction in test stimuli, and in 135° or 45° oblique direction in mask stimuli. The SOA was varied from 0 to 100 ms (backward masking). In Experiment 2, red and blue random dot patterns were used as both test and mask stimuli, with SOAs of –100 to 100 ms (forward and backward masking). The subject was asked to report the number of bars or dots as quickly as possible. The results of four subjects in one experiment and five in the other indicated that masking effects were generally greater when the test and mask stimuli were the same in orientation or color than when they were different. Slightly asymmetrical U-shaped functions were obtained both in the same and in different (orientation or color) conditions. A two-factor model with a similarity-related symmetrical integration process and a similarity-unrelated asymmetrical interuption process was considered.Experiment 1 was conducted by the first and third authors at Chiba University, and Experiment 2 was performed by the first and second authors at the University of Tokyo     

Relationship between years of training and judged performance in Shotokan karate black-belts

The relation between length of training and Dan rank was significant for 110 male black-belts, although the complication of tied ranks was noted.