Modulation of tremor amplitude during deep brain stimulation at different frequencies

Rest tremor was quantified in the index finger tip of 16 patients with Parkinson's disease (PD) receiving deep brain stimulation (DBS) of the ventro-intermediate nucleus (Vim) of the thalamus, the subthalamic nucleus (STN), or the internal part of the globus pallidus (GPi) while being off L-dopa for 12h. Clinically, without DBS, tremor amplitude varied from absent to high. Tremor was recorded continuously for about 5 min under three conditions of DBS repeated twice, namely, effective frequency (E), ineffective frequency (I), and no DBS (O). No changes in tremor were observed across conditions in subjects with little or no tremor. However, in subjects with moderate to large amplitude tremor, DBS decreased tremor amplitude to near normal values within a few seconds. Generally, transitions were progressive and occurred with a varying time delay. Occasionally, tremor escaped from control regardless of the stimulation condition considered. In some cases tremor amplitude in one condition appeared to depend on the preceding condition. Finally, the results were reproducible on two consecutive days. We conclude that tremor control with DBS follows specific dynamical rules, which must be compatible with the hypotheses proposed regarding the underlying mechanisms of DBS.     

When parallel processing in visual word recognition is not enough: new evidence from naming

Low-frequency irregular words are named more slowly and are more error prone than low-frequency regular words (the regularity effect). Rastle and Coltheart (1999) reported that this irregularity cost is modulated by the serial position of the irregular grapheme-phoneme correspondence, such that words with early irregularities exhibit a larger cost than words with late ones. They argued that these data implicate rule-based serial processing, and they also reported a successful simulation with a model that has a rule-based serial component—the DRC model of reading aloud (Coltheart, Rastle, Perry, Langdon, & Ziegler, 2001). However, Zorzi (2000) also simulated these data with a model that operates solely in parallel. Furthermore, Kwantes and Mewhort (1999) simulated these data with a serial processing model that has no rules for converting orthography to phonology. The human data reported by Rastle and Coltheart therefore neither require a serial processing account, nor successfully discriminate among a number of computational models of reading aloud. New data are presented wherein an interaction between the effects of regularity and serial position of irregularity is again reported for human readers. The DRC model simulated this interaction; no other implemented computational model does so. The present results are thus consistent with rule-based serial processing in reading aloud.     

New mothers and their babies: attachment in the face of maternal life-threatening illness

Life-threatening illness in the mothers of babies or young children is rare. Its impact is discussed in this paper, which focuses on attachment theory as a foundation for work in this area. A single case study is used to illustrate the potential conflicts and dilemmas for professionals caring for babies and their families in this situation.     

Studying Sexual Harassment in the Laboratory: Are Egalitarian Women at Higher Risk?

A laboratory experiment is reported in whichmale participants in Northern Italy (N = 120 universitystudents) were given the opportunity to sendpornographic material to a female interaction partner(“computer harassmentparadigm”). The allegedgender-role orientation of the female (traditional vs.egalitarian) and the construal of the interaction aseither intergroup or interpersonal were variedsystematically. Results show that participants molest femaleinteraction partners more when they express egalitarianrather than traditional gender-role attitudes; this isparticularly true for males with a high propensity to harass (high scores on likelihood of sexualharassment scale, Pryor, 1987), with sexist attitudes,with a strong identification as “males,” andfor low self-monitors. Also, males with a highpropensity to harass were more likely to harass theirinteraction partner when they perceived the situation asa male-female inter-group setting (rather than asinterpersonal). Results are interpreted as supporting a social identity account ofmisogyny.     

Bayesian estimation and testing of structural equation models

The Gibbs sampler can be used to obtain samples of arbitrary size from the posterior distribution over the parameters of a structural equation model (SEM) given covariance data and a prior distribution over the parameters. Point estimates, standard deviations and interval estimates for the parameters can be computed from these samples. If the prior distribution over the parameters is uninformative, the posterior is proportional to the likelihood, and asymptotically the inferences based on the Gibbs sample are the same as those based on the maximum likelihood solution, for example, output from LISREL or EQS. In small samples, however, the likelihood surface is not Gaussian and in some cases contains local maxima. Nevertheless, the Gibbs sample comes from the correct posterior distribution over the parameters regardless of the sample size and the shape of the likelihood surface. With an informative prior distribution over the parameters, the posterior can be used to make inferences about the parameters underidentified models, as we illustrate on a simple errors-in-variables model.We thank David Spiegelhalter for suggesting applying the Gibbs sampler to structural equation models to the first author at a 1994 workshop in Wiesbaden. We thank Ulf Böckenholt, Chris Meek, Marijtje van Duijn, Clark Glymour, Ivo Molenaar, Steve Klepper, Thomas Richardson, Teddy Seidenfeld, and Tom Snijders for helpful discussions, mathematical advice, and critiques of earlier drafts of this paper.     

The Identity Status Approach: In Need of Fundamental Revision and Qualitative Change

This article is a response to the commentaries of Waterman (this issue) and Berzonsky and Adams (this issue) on my review of the identity status field (van Hoof, this issue). The commentaries illustrate that the identity status researchers attribute different meanings to the identity statuses and identity status research; while Waterman finds it difficult to recognize the field in my review, Berzonsky and Adams agree with several of my conclusions. The two commentaries represent two pillars on which the status approach rests. The difference between the review and the commentaries is that the first includes both pillars, whereas each commentary consists primarily of a selective presentation of assumptions and data. This response focuses on two main points of the commentaries: (a) are the statuses sufficiently validated? and (b) to what extent are they suitable for testing developmental identity hypotheses? Using specific examples I show that the line of reasoning in the commentaries and the data proposed in support of these arguments in fact often support the conclusions of my review, for I demonstrate that the statuses are insufficiently validated and that the statuses are unsuitable for measuring identity development. These conclusions call for a fundamental revision of the identity status approach and a qualitative change in identity theory and research. Finally, the alternative approaches presented by Berzonsky and Adams are evaluated with respect to their contribution to an indispensable qualitative change in the identity status field.     

Testing the Structured Free Recall Intervention for Reducing the Impact of Bodyweight-Based Stereotypes on Performance Ratings in Immediate and Delayed Contexts

Purpose

This article investigates the efficacy of the Structured Free Recall Intervention (SFRI; J Bus Psychol 15:229?C246, 2000a; Organ Behav Hum Decis Process 82:237?C267, 2000b ) for reducing the impact of bodyweight-based stereotype endorsement on performance ratings, both immediately and when a time delay occurs between the observation and rating of performance.

Design/Methodology/Approach

512 undergraduates participated in a 2?×?2?×?2 between-subjects factorial experiment. A measure of bodyweight-based stereotype endorsement was pre-screened, and participants were randomly assigned to (a) either a no-delay or two-day time delay condition, (b) view either an average bodyweight or overweight ratee, and (c) undergo the SFRI or not.

Findings

Results suggest that (a) bodyweight-based stereotype endorsement predicts performance ratings for overweight ratees, (b) the SFRI is effective at reducing the impact of such stereotypes on performance ratings when conducted immediately after the observation of performance, and (c) the SFRI maintains this efficacy after a two-day delay between the observation and rating of performance.

Implications

These findings suggest that the best real-world application of the SFRI paradigm may be to situations with minimal delays between the observation and rating of performance, such as selection assessment centers or pre-employment interviews.

Originality/Value

Drawing on theories from the cognitive information processing literature, this paper extends previous research regarding the efficacy of the SFRI by demonstrating that short time delays between performance observation and rating??a common organizational phenomena??have minimal observed effects on the efficacy of the SFRI as a performance rating intervention.