Analysis of individual differences in multidimensional scaling via an n-way generalization of “Eckart-Young” decomposition

An individual differences model for multidimensional scaling is outlined in which individuals are assumed differentially to weight the several dimensions of a common “psychological space”. A corresponding method of analyzing similarities data is proposed, involving a generalization of “Eckart-Young analysis” to decomposition of three-way (or higher-way) tables. In the present case this decomposition is applied to a derived three-way table of scalar products between stimuli for individuals. This analysis yields a stimulus by dimensions coordinate matrix and a subjects by dimensions matrix of weights. This method is illustrated with data on auditory stimuli and on perception of nations.     

Fitting one matrix to another under choice of a central dilation and a rigid motion

A least squares method is presented for fitting a given matrixA to another given matrixB under choice of an unknown rotation, an unknown translation, and an unknown central dilation. The procedure may be useful to investigators who wish to compare results obtained with nonmetric scaling techniques across samples or who wish to compare such results with those obtained by conventional factor analytic techniques on the same sample.Part of this work was done while the senior author held a visiting research fellowship at the Educational Testing Service, Princeton, New Jersey.     

Humean Justified Belief

Orthodoxy has it that Hume was a sceptic with respect to justified beliefs about matters of fact. Tom Beauchamp, Alexander Rosenberg and Michael Costa have argued in the face of this traditional interpretation by proposing that Hume held something like an account of justification according to which we do sometimes justifiedly believe matters of fact. I consider the arguments raised by these authors, and argue that though they are correct in suggesting that Hume sketched considerations distinguishing beliefs as more or less justified, they have misunderstood Hume in certain critical respects.     

Three-year stability of WISC-R factor scores for black and white, female and male children classified as learning-disabled

Wechsler Intelligence Scale for Children-Revised (WISC-R) test and retest scores for a homogeneous sample (N=322) of approximately equal numbers of black and white, female and male learning-disabled children were compared over 3 years for factor structure and factor structure stability. These analyses were also conducted with a subsample (N=229) of the total sample for whom Digit Span scores were available. The socioeconomic status of children in the sample was determined by parents' occupation. The results suggested that WISC-R factor structure was stable over 3 years. Two-and three-factor solutions were found for the total group; three factors were found when Digit Span was included in the analysis. Coefficients of congruence indicated factorial similarity between groups of black and white, female and male children classified as learning-disabled.     

Microcomputer-based organizational survey assessment: Applications to training

As sophisticated technology continues to impact on organizations, a growing need for efficient, flexible and cost effective training programs becomes paramount. To cope with these increased training demands, many organizations have turned to Computer Based Training (CBT). The present paper describes a XENIX-based IBM PC/AT Computerized Executive Network Survey System (CENSUS) which can interface with CBT training programs to enhance training quality and assess training effectiveness. The multi-user support capabilities of CENSUS allow training-related surveys to be conducted in a more efficient, accurate and reliable manner than paper and pencil instruments. It is this microcomputer-based multi-user system, unique to CENSUS, that may provide an alternative delivery system for microcomputer-based training programs in the future.The opinions expressed in this article are those of the authors, they are not official, and do not necessarily reflect the views of the Navy Department. The authors appreciate the help of Mitch Vicino, John Kantor, Marie Thomas, Catherine Riordan, and Jack Edwards.     

Learning artificial orthographies: Further evidence of a nonanalytic acquisition procedure

Previous research (Byrne, 1984) showed that adults who learned to read an orthography representing phonetic features (voicing, place of articulation) did not readily obtain usable knowledge of the mapping of phonetic features onto orthographic elements, as evidenced by failure to generalize to partially new stimuli. The present Experiment 1 used a different method of detecting learning savings during acquisition. Subjects learned a set of complex symbols standing for phones, with the elements representing voicing and place. In a second acquisition set, the signs for voicing were reversed. Learning speed was not affected, which was consistent with the claim that feature-element links went unnoticed in initial acquisition. In Experiment 2, some subjects were instructed to "find the rule" embodied in the orthography. None did, and acquisition rates were no different from those of uninstructed subjects. In Experiment 3, subjects had 4 h of training on the orthography, with consistent feature-symbol mapping for half of the subjects and arbitrary pairings for the remainder. No reaction time advantage emerged in the consistent condition, which is further evidence of nonanalytic acquisition. The results are related to data from children learning to read.     

Concurrent phencyclidine and saccharin access: presentation of an alternative reinforcer reduces drug intake.

Six monkeys self-administered orally delivered phencyclidine ("angel dust") and saccharin under concurrent fixed-ratio 16 schedules during daily three-hour sessions. Liquid deliveries were contingent upon lip-contact responses on solenoid-operated drinking spouts. Three saccharin concentrations (0.003%, 0.03% and 0.3%, wt/vol) were tested in a nonsystematic order. For each saccharin concentration, the following series of phencyclidine concentrations (mg/ml) was presented: 0.25, 0.5, 1, 0.25 (retest), 0.125, 0.0625, 0.0312, 0.25 (retest) and 0 (water with stimuli signaling phencyclidine). As the saccharin concentration increased, the number of drug deliveries decreased, and the peaks of the concentration-response functions were shifted to the right. The lowest saccharin concentration (0.003%, wt/vol) maintained responding in excess of phencyclidine levels in only one monkey. The two higher saccharin concentrations maintained behavior far in excess of phencyclidine, but saccharin deliveries decreased in some monkeys as phencyclidine concentration and intake (mg/kg) increased. The time course and patterns of phencyclidine-reinforced responding were also altered when saccharin was concurrently available. The results are discussed in terms of strategies to reduce drug-reinforced behavior, preference between different reinforcers, and measures of reinforcing efficacy.     

Role of timing of visual monitoring and motor rehearsal in observational learning of action patterns

This experiment tested the hypothesis that observational learning is enhanced by visual monitoring of enactments that is optimally timed for conception-action matching and by motor rehearsal that serves to refine the cognitive representation. Subjects observed a modeled action pattern, after which they enacted it with either concurrent, delayed, or no visual monitoring. They then engaged in motor rehearsal or did not rehearse the action pattern. Development of the cognitive representation of the modeled action was also measured. Concurrent visual monitoring of enactments greatly facilitated observational learning, whereas delayed visual monitoring did not affect the acquisition process. Rehearsal aided cognitive representation and behavioral reproduction. The more accurate the cognitive representation of the modeled action pattern, the more skilled were the subsequent reproductions of it. After gaining proficiency in converting conception to action, subjects showed no decline in reproduction accuracy when modeling and visual monitoring were withdrawn.