Comparison of behaviors elicited by electrical brain stimulation in dorsal brain stem and hypothalamus of rats.

Four brain-stimulation phenomena elicited from both dorsal brain stem and hypothalamic sites were investigated with the following results: (a) intracranial self-stimulation rate-intensity functions for dorsal brain stem and hypothalamic sites yielded very high (over 1,000 responses/15 min.) to moderate (201-500 responses/15 min.) response rates; (b) d-amphetamine produced higher response rates than either l-amphetamine or saline at both dorsal brain stem and hypothalamic sites, indicating that noradrenergic dorsal brain stem fibers (or cell bodies) support intracranial self-stimulation; (c) dorsal brain stem and hypothalamic self-stimulation sites reliably produced escape behavior; (d) simultaneous stimulation of dorsal brain stem and hypothalamic sites at subthreshold intensities interacted to produce suprathreshold response rates.     

Gender and its contribution to the prediction of cognitive abilities at 5 years

Gender-related differences in the prediction of five year-olds' cognitive abilities from measures of distal environment, proximal environment and infant test scores were examined in a random sample of 93 boys and 90 girls. Distal environmental data included maternal IQ, maternal and paternal education. Proximal environmental data included two variables derived from the Home Screening Questionnaire: the Home Questions and the Toy Checklist. The Bayley MDI was administered at age 13 months, whereas WPPSI-R was used as cognitive outcome measure at age 5 years. The relationship between paternal education and child IQ, and between proximal environmental variables and child IQ was significantly stronger for boys than for girls. The associations between proximal environment and IQ in boys, were accounted for by the distal environmental variables. Bayley MDI correlated significantly higher with girls' IQ compared to boys' IQ. Findings are discussed in terms of parental gender-differentiated socialization processes.     

Observing responses and uncertainty reduction

Rhesus monkeys and baboons were placed in an observing response situation where on any trial they could work for food in the presence of an imposed stimulus or make an observing response by pressing a lever to present an alternative stimulus. The reinforcing properties of the alternative stimulus were assessed by placing the observing response on a progressive ratio schedule and were found to vary as a function of the difficulty of the imposed discrimination and the degree to which the imposed discrimination had been learned. The results are consistent with the hypothesis that the reinforcing strength of the alternative stimuli varies with the amount of uncertainty they reduce. Eliminating the response requirement showed that the effect was not simply due to the fact that informative stimuli permitted a saving of responses.     

A PHENOMENOLOGICAL APPROACH TO AUTOKINESIS

Analysis has shown that autokinesis constitutes a complex group of phenomena. Certain autokinetic movements ('paradoxical', i.e. experienced displacement without movement or vice versa) could not be adequately recorded by the 'tracing method', very often employed, or by other forms of purely physical registration. Autokinesis ought to be divided into a 'free' type (which may be 'paradoxical') and a 'restricted' type (always 'non-paradoxical'). 'Free' movements were experienced either in a plane perpendicular to the line of vision or as 'ad-ab' movements. 'Restricted' movements were described as either 'swinging' or 'undulating'.     

Identification and Sensitivity Analysis for Average Causal Mediation Effects with Time-Varying Treatments and Mediators: Investigating the Underlying Mechanisms of Kindergarten Retention Policy

Considering that causal mechanisms unfold over time, it is important to investigate the mechanisms over time, taking into account the time-varying features of treatments and mediators. However, identification of the average causal mediation effect in the presence of time-varying treatments and mediators is often complicated by time-varying confounding. This article aims to provide a novel approach to uncovering causal mechanisms in time-varying treatments and mediators in the presence of time-varying confounding. We provide different strategies for identification and sensitivity analysis under homogeneous and heterogeneous effects. Homogeneous effects are those in which each individual experiences the same effect, and heterogeneous effects are those in which the effects vary over individuals. Most importantly, we provide an alternative definition of average causal mediation effects that evaluates a partial mediation effect; the effect that is mediated by paths other than through an intermediate confounding variable. We argue that this alternative definition allows us to better assess at least a part of the mediated effect and provides meaningful and unique interpretations. A case study using ECLS-K data that evaluates kindergarten retention policy is offered to illustrate our proposed approach.     

Dominant paradigms in motor behavior research: the motor-action controversy revisited

In 1992, Abernethy and Sparrow published an evaluation of the historical development of the field of motor behavior research as published from 1977 up to 1988 in the Journal of Motor Behavior. The present study extends their evaluation from 1988 through 2005 using content analyses of articles on motor control and learning in this journal. Papers were categorized into the two dominant and contrasting paradigms, the motor systems approach and the action systems approach. Analysis suggests that the field of motor behavior research has changed considerably over the last three decades. The action systems approach is now the leading approach, but the motor systems approach has, however, not perished. In a Kuhnian perspective, the results might be consistent with a more long-lasting crisis, and from the available data it is not possible to predict a future outcome of the dispute between the two approaches.     

Construction, reconstruction, deconstruction: The fall of the Soviet Union from the point of view of conceptual history

The fall of the Soviet Union is analysed in conceptual terms, drawing on Reinhart Koselleck’s Begriffsgeschichte. The author seeks to interpret the instrumental role of the concepts perestrojka, glasnost′, reform, revolution, socialist pluralism, and acceleration in the Soviet collapse. The semantics and pragmatics are related to a wider intellectual and political context, and the conceptual perspective is used to help explain the progress of events. The author argues that the common notion of the reform policy concepts as clichés is not valid.