Identifying subgroups that succeed or fail with three levels of physical activity intervention: the Activity Counseling Trial.

The authors used recursive partitioning methods to identify combinations of baseline characteristics that predict 2-year physical activity success in each of 3 physical activity interventions delivered in the multisite Activity Counseling Trial. The sample consisted of 874 initially sedentary primary care patients, ages 35-75 years, who were at risk for cardiovascular disease. Predictors of 2-year success were specific to each intervention and represented a range of domains, including physiological, demographic, psychosocial, health-related, and environmental variables. The results indicate how specific patient subgroups (e.g., obese, unfit individuals; high-income individuals in stable health) may respond differently to varying levels and amounts of professional assistance and support. The methods used provide a practical first step toward identifying clinically meaningful patient subgroups for further systematic investigation.     

Prevention of nonadherence to nonsteroidal anti-inflammatory medications for newly diagnosed patients with juvenile rheumatoid arthritis.

Adherence to medications for chronic pediatric diseases decreases overtime. This randomized controlled trial evaluated a clinic-based, nurse-administered educational and behavioral intervention to prevent the anticipated drop in adherence to nonsteroidal medications among newly diagnosed patients with juvenile rheumatoid arthritis. Thirty-four participants completed the study (mean age = 8.44 years, SD = 3.96), including 19 in the experimental group and 15 in the standard-treatment (education) control group. There were significant group and Group x Time effects for adherence (assessed with an electronic monitor over a 13-month period) favoring the experimental group. In contrast, the groups did not differ significantly in disease activity or functional limitations. Factors that may have prevented detection of differences in these health parameters are dicussed.     

Does spreading activation summate?

Summary Network models of semantic memory assume implicitly or explicitly that the degree of activation of a node is a monotonic function of the total amount of excitation reaching that node from all sources. For example, the activation level of the node representing apple should be greater if it is receiving excitation due to the activation of the nodes for fruit and pear than if only one of these neighboring nodes is activated. This notion was tested by presenting semantic primes 80 ms or 320 ms before a letter string (e.g., apple or ipple) requiring a lexical decision. The prime stimuli consisted of a pair of simultaneous items that were identical in the single prime condition (e.g., fruit/fruit or pear/pear) or different in the double prime condition (e.g., fruit/pear or pear/fruit), and were either related (target = apple) or unrelated (target = copper) to the target, or neutral. As predicted by the summation of semantic activation assumption of network models there was a larger priming effect (in the 320 ms SOA condition) following the simultaneous activation of two related nodes than following the activation of only one node.This research was supported by grants to the first author from the Natural Sciences and Engineering Research Council of Canada.     

Knowledge in society: anatomy of an emergent field

An emergent social science of knowledge applications, drawing on a substantial multidisciplinary literature published over the past twenty-five years, signals an inversion of typical scholarly reasoning about the knowledge-society nexus. Whereas most scholarly research thus far has concentrated on conditions believed to affect the production of scientific and professional knowledge, we pose a new problematic: What must we examine in order to comprehend and consciously shape applications of scientific and professional knowledge to the manifold problems facing contemporary societies? To date, approaches to this problematic have proceeded on the basis of four broadly accepted if abstract theses about the nature of contemporary knowledge systems: subjectivity, corrigibility, sociality, and complexity. Within the boundaries supplied by these commonly accepted theses are unresolved controversies expressed in competing visions of complexity, alternative perspectives of causation, rival images of progress, and conflicting criteria of application.     

The sensitivity of the Bender-Gestalt Test as a screening instrument for neuropsychological impairment in older adults

We investigated the sensitivity of the Bender (1938) Visual-Motor Gestalt Test (BGT) using the Halstead-Reitan Neuropsychological Battery (HRB) as the criterion for cortical dysfunction. We studied 95 subjects over age 55 who had been diagnosed as having dementia or pseudodementia. Subjects were classified as mild, moderately, or severely impaired on the HRB and as impaired or unimpaired on the BGT. The results indicated that the BGT is less sensitive (36%) than was expected when used on an impaired geriatric population. The data further indicated that false negatives occurred more frequently with the BGT when individuals had mild neuropsychological impairment. Less frequent misclassifications occurred as the severity of impairment on HRB indices increased.     

Choice between reliable and unreliable outcomes: mixed percentage-reinforcement in concurrent chains.

Pigeons' choices between alternatives that provided different percentages of reinforcement in mixed schedules were studied using the concurrent-chains procedure. In Experiment 1, the alternatives were terminal-link schedules that were equal in delay and magnitude of reinforcement, but that provided different percentages of reinforcement, with one schedule providing, reinforcement twice as reliably as the other. All pigeons preferred the more reliable schedule, and their level of preference was not systematically affected by variation in the absolute percentage values, or in the magnitude of reinforcement. In Experiment 2, preference for a schedule providing 100% reinforcement over one providing 33% reinforcement increased systematically with increases in the duration of the terminal links. In contrast, preference decreased systematically with increases in the duration of the initial links. Experiment 3 examined choice with equal percentages of reinforcement but unequal delays to reinforcement. Preference for the shorter delay to reinforcement was not systematically affected by variation in the absolute percentage of reinforcement. The overall pattern of results supported predictions based on an extension of the delay-reduction hypothesis to choice procedures involving mixed schedules of percentage reinforcement.     

Mediating interpersonal expectancies via vocal cues: Differential speech intensity as a means of social influence

Differential vocal emphasis in the tape-recorded instruction reading for a standard person perception task was manipulated by mechanically raising or lowering the volume of the key words describing the success or failure response alternatives on the rating scale. In a series of three experiments, Ss exposed to success emphasis in the instructions rated the stimulus persons as more successful than did Ss exposed to failure emphasis. This trend was reversed for Ss who listened twice to the instructions. None of the Ss reported awareness of the influence attempt.     

The time it takes to imagine1

Stanley and Furedy (1966), using the paired-comparisons technique, reported that under conditions where size constancy held, Emmert’s law failed as distance increased beyond 90 in. Experiment 1, designed to check this report with a shorter-duration induction flash, did not yield 90 in. as the point of failure. However, although complete size constancy for direct images was again obtained, the results did not unambiguously suggest strict proportionality between afterimage size and distance. To allow a less ambiguous assessment of proportionality, Experiment 2 used magnitude-estimation procedures. Distance estimates were completely veridical, but afterimage size varied only linearly, and not proportionally, with apparent distance. It was concluded the Boring (1940) was mistaken in his attempt to reduce size constancy and Emmert’s law to the same principle.