Probability matching

The class of symmetric path-independent models with experimenter-controlled events is considered in conjunction with two-choice probability learning experiments. Various refinements of the notion of probability matching are defined, and the incidence of these properties within this class is studied. It is shown that the linear models are the only models of this class that predict a certain phenomenon that we call stationary probability matching. It is also shown that models within this class that possess an additional property called marginal constancy predict approximate probability matching.This research grew out of questions posed by William K. Estes. We are also indebted to Professor Estes for his encouragement and assistance at all stages of this research. During the course of this research J. I. Y. received support from the U. S. Public Health Service (N. I. M. H.). M. F. N.'s present address is the University of Pennsylvania. J. I. Y.'s present address is the University of Minnesota.     

Studies in measurement of the relations among sovereign states

This article describes the application of three psychometric methods to the problem of measurement of the friendly or hostile relations among states of the world today. To secure judgments, schedules were sent to students of international affairs at several times during the last five years. The method of equal-appearing intervals was used to determine the relative probability of war for 88 pairs of states in January, 1937; the method of triadic combinations to determine relative friendliness among the Great Powers in November, 1938; and the method of multidimensional or group rank order to measure the attitudes of important states toward the Great Powers in March and April, 1939; June, 1940; and June, 1941. A chart of scale values for the pairs of Great Powers shows the changing trends since 1937. The last two methods were used to depict the Great Powers in multidimensional space according to their mutual friendliness, thus permitting the application of a type of factor analysis. The reliability of the methods employed was high, and various types of evidence support the general validity of the results.The writer is indebted to Professors Quincy Wright, and L. L. Thurstone and Dr. M. W. Richardson, for advice at various stages in these studies.     

Stressful life events, bipolar disorder, and the "kindling model"

A common misconception is that bipolar disorder is an endogenous process. However, previous research suggests a role for life events in the onset of and recovery from bipolar episodes. Yet, there remains some question as to whether the relationship between life events and onset changes over the course of the disorder as a result of the number of episodes an individual has experienced. Using a rigorous interview measure of stressful life events, the current study tested the kindling model (R. M. Post, 1992), which theorizes that major life events play a diminishing role over the course of illness in bipolar patients. Analyses revealed that the number of episodes experienced does not appear to have a significant effect on bipolar 1 patients' reactivity to external stressors. In addition, the results suggest that a more complex relationship exists among age, stress, and onset of new episodes than can be adequately explained by the kindling model.     

First Order Common Knowledge Logics

In this paper we investigate first order common knowledge logics; i.e., modal epistemic logics based on first order logic with common knowledge operators. It is shown that even rather weak fragments of first order common knowledge logics are not recursively axiomatizable. This applies, for example, to fragments which allow to reason about names only; that is to say, fragments the first order part of which is based on constant symbols and the equality symbol only. Then formal properties of "quantifying into" epistemic contexts are investigated. The results are illustrated by means of epistemic representations of Nash Equilibria for finite games with mixed strategies.     

Recruitment of degrees of freedom stabilizes coordination

By showing that transitions may be obviated by recruiting degrees of freedom in the coupled pendulum paradigm, the authors reveal a novel mechanism for coordinative flexibility. In Experiment 1, participants swung pairs of unconstrained pendulums in 2 planes of motion (sagittal and frontal) at 8 movement frequencies starting from either an in-phase or antiphase mode. Few transitions were observed. Measures of spatial trajectory showed recruitment effects tied to the stability of the initial coordinative pattern. When the motion of the pendulums was physically restricted to a single plane in Experiment 2, transitions were more common, indicating that recruitment delays--or even eliminates--transitions. Such recruitment complements transitions as a source of coordinative flexibility and is incorporated in a simple extension of the Haken-Kelso-Bunz (1985) model.     

Legal and ethical issues involved when counseling minors in nonschool settings

Many counselors in non-school settings will work with children at some time during their practice; therefore, it is essential that they understand the legal and ethical issues relevant to working with minors. Major court cases and legislation are presented, and 4 critical ethical issues--counselor competence, the client's rights to confidentiality and informed consent, and duties related to child abuse--are addressed. Suggestions for working ethically with minors in order to limit legal liability are presented.     

The reliability and validity of the Perceived Stigmatization Questionnaire (PSQ) and the Social Comfort Questionnaire (SCQ) among an adult burn survivor sample

In this study, 361 adult burn survivors completed the Perceived Stigmatization Questionnaire (PSQ), the Social Comfort Questionnaire (SCQ), and other measures. Both the PSQ and SCQ had good internal consistency indices. Factor analysis of the PSQ yielded 3 factors (absence of friendly behavior, confused/staring behavior, and hostile behavior). The SCQ had 1 factor. Conjoint factor analysis with measures of related constructs (body esteem, body-esteem importance, depression, social support) suggested that PSQ and SCQ measure distinct constructs. Correlations with the related psychosocial constructs and burn characteristics suggested the PSQ and SCQ have good convergent and discriminant validity. Limitations of the study are discussed.     

The contribution of peripheral and central vision in the control of movement amplitude

Past research has revealed that central vision is more important than peripheral vision in controlling the amplitude of target-directed aiming movements. However, the extent to which central vision contributes to movement planning versus online control is unclear. Since participants usually fixate the target very early in the limb trajectory, the limb enters the central visual field during the late stages of movement. Hence, there may be insufficient time for central vision to be processed online to correct errors during movement execution. Instead, information from central vision may be processed offline and utilised as a form of knowledge of results, enhancing the programming of subsequent trials. In the present research, variability in limb trajectories was analysed to determine the extent to which peripheral and central vision is used to detect and correct errors during movement execution. Participants performed manual aiming movements of 450 ms under four different visual conditions: full vision, peripheral vision, central vision, no vision. The results revealed that participants utilised visual information from both the central and peripheral visual fields to adjust limb trajectories during movement execution. However, visual information from the central visual field was used more effectively to correct errors online compared to visual information from the peripheral visual field.     

Age-related deficits in guided search using cues

The ability of young and older adults to engage in guided conjunction search was tested in 2 experiments. In the cued condition, a picture of the target was presented before the search. In the noncued condition, there was no picture of the target. In Experiment 1, the cue was presented for 200 ms; the magnitude of the cuing effect (noncued response time--cued response time) was greater for the young than for the older observers. In Experiment 2 (older observers only), the cue duration was doubled, and older observers had a larger magnitude of cuing effect than found in Experiment 1 but not as large as what would be expected under generalized slowing. The results indicated that older observers had difficulty with interpreting the cue and setting search parameters when the target varied across trials.     

Decoupling neural networks from reality: dissociative experiences in torture victims are reflected in abnormal brain waves in left frontal cortex

From a neuroscience perspective, little is known about the long-term effect of torture. Dissociative experiences and posttraumatic stress disorder are often the results of this experience. We examined psychological dissociation within a group of 23 torture victims and report its manifestations within neural networks in the human brain. In particular, we observed that dissociative experiences are associated with slow abnormal brain waves generated in left ventrolateral frontal cortex. Given that focal slow waves often result from depriving neural networks of major input, the present results may indicate decoupling of frontal affective processors from left cortical language areas. This interpretation is consistent with the fact that disturbed access to structured verbal memory concerning traumatic events is a core feature of the dissociative experience.