Cohesiveness and performance: Covariation and causality in an undersea environment

The relationship between group cohesiveness and performance was investigated using data from a field setting. An index of leisure time cohesion correlated highly with work performance, accounting for 42% of performance variance. Although many studies assume that cohesiveness causes performance, in many contexts the dominant direction of causality may be from performance to cohesiveness instead. Laboratory experimental studies impose a causal direction and thus cannot answer a question of this kind. It was concluded, at least in the context of this study, that cohesiveness was not an important determinant of performance, but that good performance may well have been a cause of cohesiveness.     

Effects of computer-mediated vocational guidance procedures: Accuracy of self-knowledge

To assess the effectiveness of vocational guidance procedures proposed for inclusion in a computer-based vocational exploration system, 128 11th-grade male subjects were randomly assigned to three experimental groups and a control group. One group was given a computer-generated accuracy of self-knowledge feedback, another group was taught on occupational classification scheme, a third group experienced both. Measures of self-knowledge showed increased accuracy about intelligence, but not about interests, after treatments that included the feedback. Increases were largely due to changes in subjects who originally underestimated their intelligence. A delayed posttest indicated that the increases did not persist.     

Extending generalized symmetric means to arbitrary matrix sampling designs

Generalized symmetric means are redefined in a way which allows them to be calculated for any matrix sampling design. It is proved that these sample gsm's are unbiased estimates of the analogous population gsm's. Illustrative examples are given.This paper is based on Applied Technology Center for Education Technical Memorandum 75-03-01. Special appreciation is expressed to Ken Sirotnik and Tom Knapp for their suggestions on clarifing this presentation.     

The behavioral specificity of stimulation: A systems approach to procedural distinctions of classical and instrumental conditioning

This paper presents a new methodological approach to classical Pavlovian investigations. Using a yoked group for stimulus pairing trial pacing, behavioral occurrence frequencies, sequential behavior patterns, and behavioral change dynamics are analyzed for rats in both a non-discriminative and a general setting discrimination paradigm. Theoretical issues addressed by a variety of new dependent measures are discussed, and a special emphasis is placed on comparing instrumental and classical procedures as viewed from the behavioral perspective of the subject.     

A developmental study of form discrimination in pre-school children

Using a matching-from-sample technique the discriminative ability of a group of pre-school children was tested twice, at mean ages 3-8 and 4-9, in relation to an independent test of their comprehension of the notion “same”. A sequence of three stages is described, for both shape and orientation discrimination; in the first, characterized by a large number of errors, the child appears to respond largely in terms of proximity of a comparison figure to the standard; in the second his responses reflect gross aspects of similarity between the figures in the comparison set, in that several matches are made to one standard all of which have certain attributes in common with it. Finally correct and unique choices are made. Attributes used in differentiating figures are described, and a number of theoretical and methodological problems are discussed.     

Structure in semantic memory: A probabilistic approach using a continuous response task

In the continuous response (CR) task, the subject is given the name of a familiar category and must respond with category examples within a fixed time limit. The response sequence and the interresponse times are the measured variables. A general model is proposed for performance in the CR task. The time taken to generate a response is identified with the shortest search time from among a set of simultaneous search processes. Each response has a generation probability that is a function of the parameters governing the search process durations. Data involving the category states in the United States are used to test the model. The model accounts for the performance of nearly all individuals in these data.This article is based on a dissertation completed at the University of California-Berkeley in partial fullfillment of the requirements for the Ph.D. degree in psychology. Portions of the article were presented at the joint meeting of the Psychometric and Classification Societies (June 1984) and at the meeting of the Society for Mathematical Psychology (August 1984). The authors wish to thank Barbara Mellers, Juliet Schaffer, Steve Palmer, and Eleanor Rosch for helpful comments.     

On the partitioning of squared Euclidean distance and its applications in cluster analysis

The partitioning of squared Eucliean distance between two vectors in M-dimensional space into the sum of squared lengths of vectors in mutually orthogonal subspaces is discussed and applications given to specific cluster analysis problems. Examples of how the partitioning idea can be used to help describe and interpret derived clusters, derive similarity measures for use in cluster analysis, and to design Monte Carlo studies with carefully specified types and magnitudes of differences between the underlying population mean vectors are presented. Most of the example applications presented in this paper involve the clustering of longitudinal data, but their use in cluster analysis need not be limited to this arena.