A note on some modifications of latent roots and vectors

When an arbitrary positive scalar matrix is added to a correlation matrix the latent roots of the sum are equal to the corresponding roots of the correlation matrix plus an amount equal to the scalar number of the scalar matrix. The latent vectors of the sum are identical with those of the correlation matrix. An approximation to these relationships is suggested for the case in which the sum is of a correlation matrix and of a positive semidefinite diagonal matrix. The approximation is used to allow the solution of a characteristic problem for a correlation matrix with unities in the main diagonal to provide a family of solutions for the same correlation matrix.This research has been supported by a grant from the National Institute of Mental Health, MH 7864-01.     

The number of paths and cycles in a digraph

An algorithm is presented for constructing from the adjacency matrix of a digraph the matrix of its simplen-sequences. In this matrix, thei, j entry,i j, gives the number of paths of lengthn from a pointv _i to a pointv _j ; the diagonal entryi, i gives the number of cycles of lengthn containingv _i . The method is then generalized to networks—that is, digraphs in which some value is assigned to each line. With this generalized algorithm it is possible, for a variety of value systems, to calculate the values of the paths and cycles of lengthn in a network and to construct its value matrix of simplen-sequences. The procedures for obtaining the two algorithms make use of properties of a line digraph—that is, a derived digraph whose points and lines represent the lines and adjacency of lines of the given digraph.The research reported here was supported by Grant NSF-G-17771 from the National Science Foundation. We wish to thank Professor Frank Harary for suggesting certain ways of improving an earlier draft of this paper.     

A note on a matrix criterion for unique colorability of a signed graph

A signed graph,S, is colorable if its point set can be partitioned into subsets such that all positive lines join points of the same subset and all negative lines join points of different subsets.S is uniquely colorable if there is only one such partition. Developed in this note is a new matrix, called thetype matrix ofS, which provides a classification of the way pairs of points are joined inS. Such a classification yields a criterion for colorability and unique colorability.The work reported here was supported by Grant MH 10834 from the National Institute of Mental Health.     

A computational procedure for tau correlation

Thetau coefficient is defined, and a computational procedure for tied ranks is described. The procedure maintains continuous computational checks, saves labor, and particularly facilitates the use oftau with large samples. It is also shown howtau correlation may be applied toQ-sorts with any shape of forced distribution or with unforced distributions.The procedure described was developed in connection with research at the Counseling Center, University of Chicago. The research is supported by a grant (PHS M 903) from the National Institute of Mental Health, of the National Institutes of Health, Public Health Service.     

A rapid non-parametric estimate of multi-judge reliability

A technique is presented for obtaining a rapid estimate of reliability between judges, with special reference to qualitative judgments. It is shown that reliability and discrimination are independent and that estimates of both are needed. A method of obtaining an independent estimate of multi-judge discrimination is developed. It is shown that the size of item-samples is specified by the latter method. Tests of significance for both reliability and discrimination are described.This technique was developed in connection with research at the Counseling Center, University of Chicago. This investigation was supported by a research grant (PHS M 903) from the National Institute of Mental Health, of the National Institutes of Health, Public Health Service. Acknowledgment is made to Dr. Lyle V. Jones, University of Chicago, for valuable discussions relevant to the technique. Responsibility rests, however, entirely with the writer.     

PERSONALITY CHANGE IN WOMEN PHYSICIANS FROM MEDICAL STUDENT YEARS TO MID-40S

Scales from the California Psychological Inventory's (CPI; Gough, 1987) Externality and Control clusters, in conjunction with a case study, were used to investigate personality change in a sample of women physicians who entered a Pacific Northwest medical school in 1964–1967. A core of 40 women was retested in their early 30s and mid-40s. From mid-20s to early 30s, the physicians'decreased scores on CPI's Sociability and Empathy scales indicated a greater internality. Decreases on the Responsibility and Good Impression scales indicated greater tendencies to question duties and obligations. An increase on the Achievement-via-Conformance scale indicated greater ability to achieve in structured situations. From early 30s to mid-40s, a further shift toward internality was evidenced by decreased scores on Social Presence and Self-Acceptance. Gains in leadership potential and increases on the Responsibility, Self-Control, Good Impression, and Achievement-via-Conformance scales were also noted.     

Presence and television.

Film and a number of emerging entertainment technologies offer media consumers an illusion of nonmediation known as presence. To investigate the possibility that television can evoke presence, 65 undergraduate students were shown brief examples of rapid point‐of‐view movement from commercially available videotapes on a television with either a small screen (12 inches [30.5 cm], measured diagonally) or a large screen (46 inches [116.8 cm]). Participants' responses were measured via a questionnaire and a computer‐based recording of arousal (electrodermal activity). Viewers of both televisions reported an enjoyable sense of physical movement, excitement, involvement, and a sense of participation. Furthermore, as predicted, participants who watched the large screen television thought the movement in the scenes was faster, experienced a greater sense of physical movement, enjoyed the movement to a greater extent, found the viewing experience more exciting, and were more physiologically aroused. Practical and theoretical implications are discussed.     

The relationship between differential stimulus relatedness and implicit measure effect sizes

Implicit measures have been hypothesized to allow researchers to ascertain the existence and strength of relations between stimuli, often in the context of research on attitudes. However, little controlled behavioral research has focused on whether stimulus relations, and the degree of relatedness within such relations, are indexed by implicit measures. The current study examined this issue using a behavior‐analytic implicit‐style stimulus relation indexing procedure known as the Function Acquisition Speed Test (FAST). Using a matching‐to‐sample (MTS) procedure to train stimulus equivalence relations between nonsense syllables, the number of iterations of the procedure was varied across groups of participants, hence controlling stimulus relatedness in the resulting equivalence relations. Following final exposure to the MTS procedure, participants completed a FAST. Another group of participants was exposed to a FAST procedure with word pairs of known relatedness. Results showed that increasing relatedness resulted in a linear increase in FAST effect size. These results provide the first direct empirical support for a key process‐level assumption of the implicit literature, and offer a behavior‐analytic paradigm within which to understand these effects. These results also suggest that the FAST may be a viable procedure for the quantification of emergent stimulus relations in stimulus equivalence training.