Generalized concordance

Based on a simple nonparametric procedure for comparing two proximity matrices, a measure of concordance is introduced that is appropriate whenK independent proximity matrices are available. In addition to the development of a general concept of concordance and specific techniques for its evaluation within and between the subsets of a partition of theK matrices, several methods are also suggested for comparing and/or for fitting a particular structure to the given data. Finally, brief indications are provided as to how the well-known notion of concordance forK rank orders can be included within the more general framework.Partial support for this research was supplied by the National Science Foundation through SOC-77-28227.     

Evaluation of two test-anxiety reduction treatments in a secondary prevention program

The study evaluated the effectiveness of both a new anxiety management training program and a cognitive modification procedure as part of a secondary prevention effort to identify and treat test anxiety early in the academic career of college students. Subjects were 40 college freshmen who had been identified as high test-anxious in an initial mail-out survey of the Test Anxiety scale. Subjects were randomly assigned to three experimental conditions: anxiety management training, a cognitive modification procedure, and a no-treatment control group. Results indicated that both the cognitive modification and anxiety management training treatments were effective in reducing test anxiety on a posttreatment administration of the Test Anxiety scale. Especially interesting, a significant difference in academic performance emerged between treatment and control groups three semesters after treatment, underscoring the preventive value of the program.     

Analyzing stereotypes of women in the work force

The effects of three role stereotypes on three socialization factors are investigated in a pilot study of over 1,700 women entering male-dominated skilled labor fields. Canonical correlation is used to analyze the data as an example of an appropriate technique for investigating such two-component multivariate relationships.     

Transfer of persistence to the acquisition of a new behaviour

Two experiments tested whether the degree of effort required for the reinforcement of one behaviour would affect the acquisition of a second behaviour. In the first experiment, rats were placed in a conditioning chamber and: (a) were required to press a lever for food pellets on a fixed ratio schedule, (b) received free presentation of the pellets, or (c) did not receive pellets. Next, all rats were rewarded for a new behaviour, round trips across the length of a runway. As predicted, the fixed-ratio group had the greatest shuttle rate. In the second experiment, two groups were required to press a lever, and the number of presses per pellet was varied. For two other groups not required to press the lever, the amount of food presented per approach to the feeder was varied. The greater required number of lever presses and the lesser number of pellets per approach to the feeder produced the higher subsequent shuttle rates. Two alternative explanations were compared: the degree of accustomed effort per reinforcer becomes a learned component of behaviour, or high effort increases the habituation of frustration-produced disruptive responses.     

A microprocessor-based psychopathology laboratory: II. Research goals and design prerequisites

The design of a microprocessor-based psychopathology laboratory is influenced by (1) special procedures in many experimental paradigms and (2) some theoretical considerations about psychopathological data. In terms of design prerequisites, these are summarized as flexibility and power to control a spectrum of experiments, large data-processing capacity, ability to provide clinically relevant data on short notice, mobility, and simplicity of operation and programming.     

The Effects of Opening Statements on Mock Jurors' Verdicts in a Simulated Criminal Trial1

Twenty-nine male and 37 female adults served as mock jurors in a simulated criminal trial in which the amount of preview offered in both the prosecution's and defense's opening statements was factorially varied. It was found that the effects upon verdicts of guilt of the amount of preview in either side's opening statement depended on that in the other side's opening statement. Extensive prosecution opening statements led to more guilty verdicts only when the de fense's opening statement was also extensive; when the defense's opening statement was brief, participants tended to find the defendant guilty regardless of the amount of preview in the prosecution's opening statement. Extensive opening statements from the defense led to more not-guilty verdicts only when the prosecution's opening statement was brief. Results from a series of mid-trial measures indicated that opening statements predisposed jurors to favor one side or the other very early in the trial, and that jurors tended to maintain this predisposition throughout the course of the trial. It was suggested that opening statements serve to create thematic frameworks which the jurors use to assist them in their processing of trial information. Implications for legal practice were also discussed.     

TOWARD A METHODOLOGY OF WITHDRAWAL DESIGNS FOR THE ASSESSMENT OF RESPONSE MAINTENANCE

Single-case experimental designs have advanced considerably in the evaluation of functional relationships between interventions and behavior change. The systematic investigation of response maintenance once intervention effects have been demonstrated has, however, received relatively little attention. The lack of research on maintenance may stem in part from the paucity of design options that systematically evaluate factors that contribute to maintenance. The present paper discusses three design options potentially useful for the investigation of response maintenance. These include: (a) the sequential-withdrawal, (b) the partial-withdrawal, and (c) the partial-sequential withdrawal designs. Each design is illustrated and potential limitations are discussed.     

A heuristic method for the comparison of related structures

By extending a technique for testing the difference between two dependent correlations developed by Wolfe, a strategy is proposed in a more general matrix context for evaluating a variety of data analysis schemes that are supposed to clarify the structure underlying a set of proximity measures. In the applications considered, a data analysis scheme is assumed to reconstruct in matrix form the given data set (represented as a proximity matrix) based on some specific model or procedure. Thus, an evaluation of the adequacy of reconstruction can be developed by comparing matrices, one containing the original proximities and the second containing the reconstructed values. Possible applications in multidimensional scaling, clustering, and related contexts are emphasized using four broad categories: (a) Given two different reconstructions based on a single data set, does either represent the data significantly better than the other? (b) Given two reconstructions based on a single data set using two different procedures (or possibly, two distinct data sets and a common method), is either reconstruction significantly closer to a particular theoretical structure that is assumed to underlie the data (where the latter is also represented in matrix form)? (c) Given two theoretical structures and one reconstruction based on a single data set, does either represent the reconstruction better than the other? (d) Given a single reconstruction based on one data set, is the information present in the data accounted for satisfactorily by the reconstruction? In all cases, these tasks can be approached by a nonparametric procedure that assesses the similarity in pattern between two appropriately defined matrices. The latter are obtained from the original data, the reconstructions, and/or the theoretical structures. Finally, two numerical examples are given to illustrate the more general discussion.     

Patterns of human interlimb coordination emerge from the properties of non-linear, limit cycle oscillatory processes: theory and data

The present article represents an initial attempt to offer a principled solution to a fundamental problem of movement identified by Bernstein (1967), namely, how the degrees of freedom of the motor system are regulated. Conventional views of movement control focus on motor programs or closed-loop devices and have little or nothing to say on this matter. As an appropriate conceptual framework we offer Iberall and his colleagues' physical theory of homeokinetics first elaborated for movement by Kugler, Kelso, and Turvey (1980). Homeo kinetic theory characterizes biological systems as ensembles of non-linear, limit cycle oscillatory processes couple and mutually entrained at all the levels of organization. Patterns of interlimb coordination may be predicted from the properties of non-linear, limit cycle oscillators. In a set of experiments and formal demonstrations we show that cyclical, two-handed movements maintain fixed amplitude and frequency ( a stable limit cycle organization) under the following conditions: (a) when brief and constantly applied load perturbations are imposed on one hand or the other, (b) regardless of the presence or absence of fixed mechanical constraints, and (c) in the face of a range of external driving frequencies from a visual source. In addition, we observe a tight phasic relationship between the hands before and after perturbations (quantified by cross-correlation techniques), a tendency of one limb to entrain the other (mutual entrainment) and that limbs cycling at different frequencies reveal non-arbitrary, sub-harmonic relationships (small integer, subharmonic entrainment). In short, all the above patterns of interlimb coordination fall out of a non-linear oscillatory design. Discussion focuses on the compatibility of these results with past and present neurobiological work, and the theoretical insights into problems of movement offered by homeokinetic physics. Among these are, we think, the beginnings of a principled solution to the degrees of freedom problem, and the tentative claim that coordination and control are emergent consequences of dynamical interaction among non-linear, limit cycle oscillatory processes.