Interactive scaling with individual subjects

A metric multidimensional scaling (MDS) procedure based on computer-subject interaction is developed, and an experiment designed to validate the procedure is presented. The interactive MDS system allows generalization of current MDS systems in two directions: (a) very large numbers of stimuli may be scaled; and (b) the scaling is performed with individual subjects, facilitating the investigation of individual as well as group processes. The experiment provided positive support for the interactive MDS system. Specifically, (a) individual data are amenable to meaningful interpretation, and they provide a tentative basis for quantitative investigation; and (b) grouped data provide meaningful interpretive and quantitative results which are equivalent to results from standard paired-comparisons methods.This report was supported in part by a PHS research grant, No. M-10006, from the National Institute of Mental Health, in part by a Science Development grant, No. GU-2059, from the National Science Foundation, both granted to the Psychometric Laboratory at the University of North Carolina, and in part by a PHS research grant, No. MH-16474, from the National Institute of Mental Health, Public Health Service, granted to the second author. The major portion of this research was performed while the second author was the L. L. Thurstone Distinguished Fellow at the Psychometric Laboratory of the University of North Carolina while on leave from the University of Southern California. The authors are indebted to Amnon Rapoport and Thomas S. Wallsten for their critical evaluations of an earlier version of this report. While this paper was entirely a cooperative effort on the part of both authors, the first author was primarily responsible for the algorithms, and the second for developing the mathematical model.     

Nonmetric multidimensional scaling: Recovery of metric information

The degree of metric determinancy afforded by nonmetric multidimensional scaling was investigated as a function of the number of points being scaled, the true dimensionality of the data being scaled, and the amount of error contained in the data being scaled. It was found 1) that if the ratio of the degrees of freedom of the data to that of the coordinates is sufficiently large then metric information is recovered even when random error is present; and 2) when the number of points being scaled increases the stress of the solution increases even though the degree of metric determinacy increases.This report was supported in part by a PHS research grant No. M-10006 from the National Institute of Mental Health, Public Health Service, and in part by a Science Development grant No. GU-2059, from the National Science Foundation. The author is indebted to Charles R. Sherman for his assistance in gathering the data and for his critical re-writing of sections of this report. The assistance of Lyle V. Jones in his critical readings and comments is also deeply appreciated.     

Coin value and perceived size: a longitudinal study.

Decimalization of the Irish currency presented an opportunity to study the perceived size of coins as they were introduced or withdrawn and to examine the accentuation of differences between coins. Estimates were obtained of the sizes of 4 coins from 478 subjects in 3 groups tested at different times: just after decimalization, 2, or 3 yr. later. A newly introduced coin was significantly underestimated in size at first but came to be significantly overestimated later, while all familiar coins were always significantly overestimated. The amount of overestimation of a coin depended on its value, not its size, leading to an accentuation of the difference between any two coins if the larger coin was also the more valuable but sometimes to the opposite if the smaller coin were of higher value than the larger member of the pair.     

Component models for three-way data: An alternating least squares algorithm with optimal scaling features

A review of the existing techniques for the analysis of three-way data revealed that none were appropriate to the wide variety of data usually encountered in psychological research, and few were capable of both isolating common information and systematically describing individual differences. An alternating least squares algorithm was proposed to fit both an individual difference model and a replications component model to three-way data which may be defined at the nominal, ordinal, interval, ratio, or mixed measurement level; which may be discrete or continuous; and which may be unconditional, matrix conditional, or row conditional. This algorithm was evaluated by a Monte Carlo study. Recovery of the original information was excellent when the correct measurement characteristics were assumed. Furthermore, the algorithm was robust to the presence of random error. In addition, the algorithm was used to fit the individual difference model to a real, binary, subject conditional data set. The findings from this application were consistent with previous research in the area of implicit personality theory and uncovered interesting systematic individual differences in the perception of political figures and roles.This paper is part of a Thesis performed by Richard Sands under the direction of Forrest Young at the L. L. Thurstone Psychometric Laboratory, University of North Carolina at Chapel Hill. Thanks are extended to Drs. Charles Schmidt and Andrea Sedlak for the use of their political role data set.     

In Defence Of The Phase Space Picture

While the Phase Space formulation of quantum mechanics has received considerable attention it has seldom been defended as a viable interpretation. In this paper I expound the Phase Space Picture, use it to provide a quasi-classical ‘hidden variables’ interpretation of quantum mechanics and offer a defence of it against various objections. This revised version was published online in June 2006 with corrections to the Cover Date.     

The principal components of mixed measurement level multivariate data: An alternating least squares method with optimal scaling features

A method is discussed which extends principal components analysis to the situation where the variables may be measured at a variety of scale levels (nominal, ordinal or interval), and where they may be either continuous or discrete. There are no restrictions on the mix of measurement characteristics and there may be any pattern of missing observations. The method scales the observations on each variable within the restrictions imposed by the variable's measurement characteristics, so that the deviation from the principal components model for a specified number of components is minimized in the least squares sense. An alternating least squares algorithm is discussed. An illustrative example is given.Copies of this paper and of the associated PRINCIPALS program may be obtained by writing to Forrest W. Young, Psychometric Laboratory, Davie Hall 013-A, Chapel Hill, NC 27514.     

Improving quality of life in diverse rural older adults: a randomized trial of a psychological treatment

The efficacy of home-delivered cognitive-behavioral therapy (CBT) in improving quality of life and reducing psychological symptoms in older adults was examined in this study. One hundred thirty-four participants, predominately African American and characterized as primarily rural, low resource, and physically frail, were randomly assigned to either CBT or a minimal support control condition. Results indicate that CBT participants evidenced significantly greater improvements in quality of life and reductions in psychological symptoms. Mediation of treatment through cognitive and behavioral variables was not found despite the acceptable delivery of CBT by research therapists. These data suggest that treatment can be effective with a disadvantaged sample of older adults and extend efficacy findings to quality of life domains. Creating access to evidence-based treatments through nontraditional delivery is an important continuing goal for geriatric health care.     

Alcohol self-administration by rats in the presence of a tangible object

The authors used the sucrose-substitution procedure to train operant self-administration of a 10% alcohol solution in 8 Long-Evans rats. After they established stable responding, they began a 10-session baseline. A 10-session experimental phase followed the baseline phase. During the experimental phase, the authors placed a large glass marble in the center of the experimental chambers before self-administration sessions. The presence of the marble decreased the rats' responding and alcohol intake significantly. The authors discussed the results in terms of distraction and the effects of concurrently available reinforcers on alcohol self-administration.