Paradoxical facilitation of attention in healthy humans

Transcranial magnetic stimulation (TMS)-induced virtual lesions in healthy subjects can be used to test neurofunctional models of disease. The interhemispheric rivalry model of heminglect is well suited for such investigations, as simple predictions derived from clinical data can be tested without the caveats normally associated with lesion studies. One of these predictions is that release from contralateral inhibition should lead to increased parietal responsiveness, which, in turn, would enhance spatial attention. Here, we detail studies showing TMS-induced paradoxical functional facilitation of attention in healthy individuals and highlight their contribution to the understanding and treatment of neglect syndromes.     

The Collaborative Longitudinal Personality Disorders Study (CLPS): overview and implications

The Collaborative Longitudinal Personality Disorders Study (CLPS; Gunderson et al., 2000) was developed to fill gaps in our understanding of the nature, course, and impact of personality disorders (PDs). Here, we review published findings to date, discuss their implications for current conceptualizations of PDs, and raise questions that warrant future consideration. We have found that PDs are more stable than major depressive disorder, but that meaningful improvements are possible and not uncommon. We have confirmed also that PDs constitute a significant public health problem, with respect to associated functional impairment, extensive treatment utilization, negative prognostic impact on major depressive disorder, and suicide risk. At the same time, we have demonstrated that dimensional models of PDs have clinical validity that categories do not, especially greater temporal stability. Furthermore, dimensional personality traits appear to be the foundation of behaviors described by many PD criteria. Taken together, our results lead us to hypothesize that PDs may be reconceptualized as hybrids of stable personality traits and intermittently expressed symptomatic behaviors.     

Dispositional and task-specific social-cognitive determinants of physical effort perseverance

The authors performed 3 studies to investigate the effects of social-cognitive variables on physical effort perseverance. Linear hierarchical regressions indicated that task-specific variables and perceived ability or competence accounted for the majority of perseverance variance in all 3 studies. The strongest single predictors in this cluster of variables were perceived competence, confidence, and readiness to invest effort. Physical self-health and ability accounted for a lesser portion of effort perseverance variance, with self-presentation confidence being the major single predictor in this cluster. The goal orientation cluster accounted for the least amount of effort perseverance variance. Together with task-specific confidence and the readiness to invest effort, as well as determination and commitment and competence, the findings support the contention that task-specific efficacious beliefs to a large extent determine persistence and endurance behaviors.     

Effects of semantic cues on mathematical modeling: Evidence from word-problem solving and equation construction tasks

Mathematical solutions to textbook word problems are correlated with semantic relations between the objects described in the problem texts. In particular, division problems usually involve functionally related objects (e.g., tulips-vases) and rarely involve categorically related objects (e.g., tulips-daisies). We examined whether middle school, high school, and college students use object relations when they solve division word problems (WP) or perform the less familiar task of representing verbal statements with algebraic equations (EQ). Both tasks involved multiplicative comparison statements with either categorically or functionally related objects (e.g., "four times as many cupcakes [commuters] as brownies [automobiles]"). Object relations affected the frequency of correct solutions in the WP task but not in the EQ task. In the latter task, object relations did affect the structure of nonalgebraic equation errors. We argue that students use object relations as "semantic cues" when they engage in the sense-making activity of mathematical modeling.     

Summation in autoshaping is affected by the similarity of the visual stimuli to the stimulation they replace

Pigeons received autoshaping with 2 stimuli, A and B, presented in adjacent regions on a television screen. Conditioning with each stimulus was therefore accompanied by stimulation that was displaced from the screen whenever the other stimulus was presented. Test trials with AB revealed stronger responding if this displaced stimulation was similar to, rather than different from, A and B. For a further experiment the training just described included trials with A and B accompanied by an additional, similar, stimulus. Responding during test trials with AB was stronger if the additional trials signaled the presence rather than the absence of food. The results are explained with a configural theory of conditioning.     

Discrimination of structure: I. Implications for connectionist theories of discrimination learning

In each of 4 experiments animals were given a structural discrimination task that involved visual patterns composed of identical features, but the spatial relations among the features were different for reinforced and nonreinforced trials. In Experiment 1 the stimuli were pairs of colored circles, and pigeons were required to discriminate between patterns that were the mirror image of each other. A related task was given to rats in Experiment 2. Subjects solved these discriminations. For Experiment 3, some pigeons were given a discrimination similar to that used in Experiment 1, which they solved, whereas others received a comparable task but with 3 colored circles present on every trial, which they failed to solve. The findings from Experiment 3 were replicated in Experiment 4 using different patterns. The results are difficult to explain by certain connectionist theories of discrimination learning, unless they are modified to take account of the way in which compound stimuli are structured.     

Sampling Bias and Other Methodological Threats to the Validity of Health Survey Research

Data from a longitudinal occupational health survey of professional fire fighters were used to explore the potential impact of two types of methodological bias: sample selection and reactivity. No significant differences on demographic variables were observed between the group who first responded after a within-study change in survey administration format (Delayed) and respondents who had completed surveys since the study's inception (Initial). However, statistically significant differences in the study's 26 outcome measures provided some evidence that between-group differences did exist and that an administration format type of response bias was also potentially present. The effect sizes associated with the 37 observed significant differences ranged from small to medium. These results provide a context for a reexamination of standard techniques for the identification and interpretation of survey research biases. Methods are suggested to strengthen tests for selection bias and to minimize the impact of response biases.     

Dimensions of distress tolerance and the moderating effects on mindfulness-based stress reduction

Background and Objectives: This study examined the relationship between distress tolerance and psychosocial changes among individuals participating in Mindfulness-Based Stress Reduction (MBSR). The objective of the analysis was to discern whether individuals with lower distress tolerance measured before MBSR showed larger reductions in perceived stress following MBSR. Design and Methods: Data were collected from a sample of convenience (n?=?372) using a quasi-experimental design. Participants completed self-report measures immediately prior to course enrollment and following course completion. Results: Perceived stress, distress tolerance, and mood states showed favorable changes from pre- to post-MBSR in the current study. Baseline distress tolerance significantly moderated reductions on perceived stress, supporting the primary hypothesis that individuals with lower baseline distress tolerance evidenced a greater decline in perceived stress following MBSR. For a one-unit increase on the self-reported baseline Distress Tolerance Scale, reported perceived stress scores decreased by 2.5 units (p?Conclusions: The finding that individuals with lower baseline distress tolerance evidenced a greater decline in perceived stress may offer hints about who is most likely to benefit from MBSR and other mindfulness-based treatments. Identifying moderators of treatment outcomes may yield important benefits in matching individuals to treatments that are most likely to work for them.