Coordination Dynamics of the Bipedal Galloping Pattern

A motion equation in relative phase was developed that incorporates the spatial-temporal pattern of the bipedal gallop along with the more commonplace patterns of the bipedal jump and walk-run. In 3 experiments, human participants (N = 6 per experiment) simulated the bipedal gait patterns through the rhythmic motions of hand-held pendulums. Predictions of the motion equation for coordination equilibria and their respective degrees of stability were confirmed. In particular, the gallop pattern was less stable than the fundamental in-phase and antiphase patterns but changed in qualitatively similar ways to those gaits as a function of limb asymmetry and movement frequency. The relation between the modeled coordination dynamics and the kinematic characteristics of real bipedal galloping is discussed     

Positive Psychological States in the Daily Life of a Sample of Working Women

This study of a sample of working women investigated where positive experiences were derived from in everyday life, focusing on the domains of work and nonwork (leisure). It examined how aspects of the situation, in terms of principal environmental influences in work and leisure, and the person, in terms of locus of control, were associated with positive subjective states and psychological well-being. The study employed questionnaires and also the experience sampling method. The results showed that both work and leisure were important for positive psychological states and that internal locus of control was associated with greater enjoyment, interest, feelings of immediate control, intrinsic motivation, life satisfaction, and affective well-being and a number of principal environmental influences.     

Stochastic ordering using the latent trait and the sum score in polytomous IRT models

In a restricted class of item response theory (IRT) models for polytomous items the unweighted total score has monotone likelihood ratio (MLR) in the latent trait. MLR implies two stochastic ordering (SO) properties, denoted SOM and SOL, which are both weaker than MLR, but very useful for measurement with IRT models. Therefore, these SO properties are investigated for a broader class of IRT models for which the MLR property does not hold.In this study, first a taxonomy is given for nonparametric and parametric models for polytomous items based on the hierarchical relationship between the models. Next, it is investigated which models have the MLR property and which have the SO properties. It is shown that all models in the taxonomy possess the SOM property. However, counterexamples illustrate that many models do not, in general, possess the even more useful SOL property.Hemker's research was supported by the Netherlands Research Council, Grant 575-67-034. Junker's research was supported in part by the National Institutes of Health, Grant CA54852, and by the National Science Foundation, Grant DMS-94.04438.     

Shrinkage estimation of linear combinations of true scores

This paper is concerned with combining observed scores from sections of tests. It is demonstrated that in the presence of population information a linear combination of true scores can be estimated more efficiently than by the same linear combination of the observed scores. Three criteria for optimality are discussed, but they yield the same solution which can be described and motivated as a multivariate shrinkage estimator.Input from Eric Bradlow, Charles Lewis, and Linda Zeger is acknowledged. Research for this paper was funded by the Program Research Council (ETS). Suggestions of the Editor and of anonymous referees were instrumental in several improvements of the paper.     

Perfectionism and Suicide Ideation in Adolescent Psychiatric Patients

This study was conducted to examine the relations between dimensions of perfectionism and suicide ideation in an adolescent psychiatric sample. A sample of 66 adolescents from an inpatient psychiatric facility completed the Child and Adolescent Perfectionism Scale, the Child's Hopelessness Scale, and the Suicide Ideation Questionnaire. Overall, the results indicated that socially prescribed perfectionism was associated with greater suicide ideation and that it, along with hopelessness, accounted for unique variance in suicide ideation scores. The findings are discussed in terms of their practical and theoretical significance as well as their consistency with similar research with adults.     

Role of Glucocorticoids on Rat Brain Metallothionein-I and -III Response to Stress

The metallothionein (MT) gene family consists of four members (MT-I through -IV) that are tightly regulated during development. Whereas MT-I and MT-II are widely expressed isoforms, MT-III has been found to be mainly expressed in the central nervous system in adult animals, and is the only isoform that inhibits survival and neurite formation of cortical neurons in vitro. A number of models of brain injury have been shown to affect MT-III mRNA levels, which has been suggested to be related to the putative neurotrophic role of this protein. However, a stress response will presumably be associated to the brain injury which could, in turn, drive MT-III regulation. In the present report the effect of a classical stress model, immobilization stress, on brain MT regulation has been studied in rats. MT-I+II protein levels were measured by radioimmunoassay in up to eight brain areas and, as expected, it was found that stress increased selectively MT-I+II levels. Adrenalectomy (ADX) had a general decreasing effect on basal MT-I+II levels; however, ADX blunted the MT-I+II response to stress in cerebellum and presumably in frontal cortex and medulla plus pons but not in the hypothalamus. MT-I mRNA measurements were in accordance with the MT-I+II protein levels in the brain areas studied. In contrast to MT-I mRNA, MT-III mRNA levels of brain cortex tended to decrease during stress, although this effect was not statistically significant. ADX also tended to decrease basal MT-III mRNA levels. Northern blot assays of pooled mRNAs suggested similar differential regulation of these two brain MT isoforms in the cerebellum. These results indicate that glucocorticoids mediate brain MT-I+II response to stress in some but not all brain areas, that a role of these hormones is likely also for MT-III, and that the regulation of MT isoforms differs substantially in the brain.     

Adaptiveness: A moderator of the adverse impact of hassles?

Adaptiveness constitutes coping consistently with Stressors so to reduce distress or, at worst, not aggravate it. Accordingly, it should moderate the adverse impact of hassles. Undergraduate volunteers (N = 200) responded to measures of hassles, adaptiveness, and the criteria of subjective distress, psychiatric symptomatology and minor physical ailments. In all three regression analyses, hassles made a substantial positive contribution and adaptiveness a small negative contribution to adverse outcome. The interaction between hassles and adaptiveness was non-significant in all three cases. Alternative interpretations were identified to guide further research.     

Behavior analysis and farm animal welfare

This article demonstrates that there is a role for behavior-analytic techniques in the area of farm animal welfare and provides examples of the kinds of work that can be done. Behavior-analytic procedures, specifically those used in the study of psychophysics, preference, and demand, can provide answers to three questions people concerned with the welfare of farm animals are likely to ask: What can the animals detect? What do they like and dislike? What will they work to attain or preserve? Such information certainly is necessary for making reasonable decisions about animal welfare, although it is not sufficient in and of itself.     

Do college studentsstill prefer companies without employment drug testing?

Two experiments examined the effects of drug testing policies on undergraduates' behavioral intentions and attitudes toward the company. Study 1 (n=267) manipulated type of drug testing and consequences of detected use. Study 2 (n=267) manipulated the presence of applicant and employee drug testing. Subjects in both studies showed stronger intentions to apply to a company with random employee testing than one with no employee testing. Study 2 also found that an interaction between company policy and subjects' attitudes toward drug testing affected attitudes toward the company. Both studies suggest that employee drug testing may now foster recruitment.Study 1 was conducted while the author was at Ohio University and was presented in an earlier version at the Eastern Psychological Association's 64th Annual Meeting, Arlington, VA, April 16–April 18, 1993.I thank Candie Burbick and Jamie Winters for their work as student assistants. I also thank Jane Kestner, Kim Mastrangelo, James Rogers, and the JBP reviewers for their suggestions.