A note on partitioned determinants

A formula for the determinant of a partitioned matrix, possibly with singular submatrices, is derived and applied to some psychometric and numerical problems.     

Generalized eigenvalue problems with positive semi-definite matrices

In a recent paper in this journal McDonald, Torii, and Nishisato show that generalized eigenvalue problems in which both matrices are singular can sometimes be solved by reducing them to similar problems of smaller order. In this paper a more extensive analysis of such problems is used to sharpen and clarify the results of McDonald, Torii, and Nishisato. Possible extensions are also indicated. The relevant mathematical literature is reviewed briefly.     

Preschool peer perceptions of the behavior of hyperactive and aggressive children

To assess if preschool children can successfully identify externalizing symptomatic behaviors in their male classmates, and if these perceptions are associated with peer-rated popularity and rejection, 154 preschool boys and girls were interviewed using a peer nomination procedure. Behavioral data on the same preschool boys (N=86) were also provided by their respective teachers. Preschool children were capable of providing stable nominations of popularity, rejection, and aggression, boys and girls significantly agreed in their nominations, and these nominations were not a function of the age of the rated child, although they differed somewhat as a function of the age of the rater. Teachers and peers reflected significant convergence in ratings of hyperactivity and aggression and teacher ratings of peer problems significantly agreed with actual peer nominations of popularity and rejection. Boys nominated as aggressive were more rejected by their classmates, whereas boys nominated as hyperactive were either more popular and /or more rejected. Limited evidence for differential patterns of relationships among hyperactivity, aggression, and peer status was obtained for both the peer and teacher data.Portions of this paper were presented as part of a symposium, W. Pelham (Chair),Peer relations in hyperactive children: Diagnostic, symptomatic, and treatment consideration, at the annual meeting of the American Psychological Association, Los Angeles, August 1981. This research was supported, in part, by NIMH grant #32992 to the first author.     

Remembering plurals: Unit of coding and form of coding during serial recall

Subjects were required to recall lists of six words which had been presented visually in sequence. One or two of the words might be plural nouns. A substantial number of errors occurred in which the plural form became detached from its original root. This is taken as evidence for a morpheme-based code as opposed to a unitary word code. A significantly high proportion of these errors maintained the form of the plural ( /S/, /Z/ or (ЪZ/) which is considered evidence for a primarily phonological coding of the plural morpheme. There is however a suggestion that on some occasions the plural is coded morphemically—i.e., in a way which does not distinguish between the various plural endings.     

Belief and Values in the Nuclear Debate1

A questionnaire was administered to 47 participants attending a workshop on nuclear energy shortly after publication of a report on a proposed nuclear fuel reprocessing plant. Supporters and opponents of the proposed development differed markedly in their estimates of its possible consequences, and of the relative importance of these consequences. They also differed in their endorsement of pro- and anti-nuclear lobbies, and the factors which they felt contributed most to the “quality of life”. Overall, pro-nuclear subjects appear to place emphasis on the economic benefits of nuclear energy, while anti-nuclear subjects appearad more concerned with social and political risks, and regraded alternative energy sources as more viable. It is concluded that an analysis of such attitudinal differences requires a consideration not only of differences in beliefs, but also of differences in belief salience.     

Evidence that a factor besides progesterone, prolactin, or plasma-estradiol-binding protein inhibits estrogen-induced sexual receptivity in pregnant rats.

Daily administration of estradiol benzoate stimulated significantly less lordotic behavior in rats during the second half of pregnancy than in ovariectomized females that received subcutaneous progesterone implants, pituitary grafts that raised plasma prolactin, or both treatments combined. Following an initial facilitation of receptivity, females with progesterone implants showed only moderate reductions in lordosis quotients over 3 test days. The capacity of plasma from pregnant rats to bind estradiol was found to increase significantly during the second half of pregnancy. However, daily administration to pregnant rats of a synthetic estrogen, R 2858, which is not bound by plasma protein, was no more effective than estradiol benzoate in stimulating receptive behavior. Administration of estradiol benzoate also stimulated significantly lower levels of sexual behavior in pregnant females than in females in which pseudopregnancy had been prolonged by previous hysterectomy or induction of uterine decidualization. These findings suggest that some endocrine factor other than progesterone, prolactin, or estradiol-binding protein is primarily responsible for the potent suppression of behavioral responsiveness to estrogen which occurs in pregnant rats. It is suggested that 5 alpha-reduced androgens may cause these behavioral effects.     

Demonstration of an aftereffect occurring in the tactile-kinesthetic domain

Summary The aim of this work is the demonstration of a tactile-kinesthetic aftereffect. A sequence of stimuli was offered to adult subjects whose task was to compare two weights presented simultaneously to both hands by means of a Piéron gravimeter. In Experiment 1 the inspection stimuli consisted of two successive presentations of unequal weights for a period of 2 × 10 s. The test stimuli consisted of two equal weights rapidly following an inspection stimulus. Control stimuli consisting of two equal weights not preceded by an inspection stimulus were interspersed in the sequence. The results obtained confirm the existence of a contrast effect after presentation of an inspection stimulus. In Experiment 2 the inspection stimuli consisted of a single presentation of two unequal weights for a period of 20 s. The results confirm those of the first experiment and provide data enabling the contrast effect obtained to be interpreted as a Köhler-type aftereffect. In order to avoid confusion with the kinesthetic-figural aftereffect, we propose to call the effect demonstrated here the Gravimetric Aftereffect.     

Youth Counselor Burnout

Counselors of unruly, runaway, truant, or delinquent children and their families run the risk of emotional overexposure– “burnout” as a result of intense client needs and problems. Survival on the job requires taking steps to avoid internalizing caseload pressures. These steps include: helping-not replacing-parents, keeping meetings brief, responding to emergencies selectively, taking simple steps first, using humor, taking care of oneself, expecting complications, avoiding panic, and knowing when to withdraw.     

Correctness of Kruskal's algorithms for monotone regression with ties

Kruskal has proposed two modifications of monotone regression that can be applied if there are ties in nonmetric scaling data. In this note we prove Kruskal's conjecture that his algorithms give the optimal least squares solution of these modified monotone regression problems. We also propose another (third) approach for dealing with ties.Comments by Dr. J. B. Kruskal have been most helpful.