Problem solving and the search for crucial evidence

Summary Four experiments are reported that examine performance on a complex reasoning task. Subjects have to determine which factory has polluted a river by ordering a series of tests for the presence or absence of various pollutants. Previous research has shown that people typically employ a non-optimal exhaustive search stragegy on this task. Experiments 1 and 2 attempt to identify some of the boundary conditions of this strategy. It is found that the order in which pollutants appear on the matrix list does not seem to be a critical factor, whereas the overall size of the factory-pollutant matrix is. Experiments 3 and 4 attempt to deter people directly from adopting the exhaustive strategy. The results show that even when people are deterred from using the exhaustive method, this will not necessarily result in their adopting a more efficient strategy.     

PROMOTING SAFETY BELT USE WITH TRAFFIC SIGNS AND PROMPTERS

Two studies were conducted examining the stimulus-control effects of conventional traffic signs as prompts for motor vehicle driver safety belt use. Following pilot research which suggested that a traffic sign reading “Fasten Safety Belt” posted at a parking lot exit was effective in producing small increases in safety belt use, Study I demonstrated the superiority of having human prompters display such signs compared to simply posting the signs. Study II replicated the findings of Study I and found that posted signs became more effective in prompting safety belt use if simple posting was preceded by a period involving human prompters who displayed the signs. The results bear upon the development of more effective use of traffic signs in promoting safety belt use and in viewing such use as an instance of rule-governed behavior.     

The three-factor structure of the Eysenck personality inventory revealed by a two-step confirmatory procedure

Evidence for the existence of the assumed three-subscale structure of the Eysenck Personality Inventory has been persistent but tenuous. It was suggested that a substantial reason for this may be the discrepancy between the numbers of items in the Lie (L) scale (9 items) and those in the other two scales [Neuroticism (N) and Extraversion (E)] which have 24 items in each. A two-step confirmatory procedure to circumvent this problem was proposed, involving a two-factor analysis of the Neuroticism and Extraversion items, followed by a three-factor analysis of equal numbers of N, E and L scale items. An analysis of the responses of 386 undergraduates demonstrating the proposed procedure revealed in the first step, quite unequivocally, the presence of Neuroticism and Extraversion factors, and in the second step, a third factor clearly congruent with the L scale.     

Implicit learning: Below the subjective threshold

In this review, we consider three possible criteria by which knowledge might be regarded as implicit or inaccessible: It might be implicit only in the sense that it is difficult to articulate freely, or it might be implicit according to either an objective threshold or a subjective threshold. We evaluate evidence for these criteria in relation to artificial grammar learning, the control of complex systems, and sequence learning, respectively. We argue that the convincing evidence is not yet in, but construing the implicit nature of implicit learning in terms of a subjective threshold is most likely to prove fruitful for future research. Furthermore, the subjective threshold criterion may demarcate qualitatively different types of knowledge. We argue that (1) implicit, rather than explicit, knowledge is often relatively inflexible in transfer to different domains, (2) implicit, rather than explicit, learning occurs when attention is focused on specific items and not underlying rules, and (3) implicit learning and the resulting knowledge are often relatively robust.     

A review of patient outcomes in pharmacological studies from the psychiatric literature, 1966–1993

A literature search was conducted on studies of new drugs used with patients with schizophrenia reported by U.S. and non-U.S. researchers from 1966–1993, yielding 41 U.S., and a total of 24 other non-U.S. studies, among them 11 British studies. Results of the U.S. and non-U.S. studies were pooled separately and compared. Among several comparable conditions discussed, the lack of any data on suicides in the U.S. studies was observed. For a second statistical analysis of suicide rates ‘person-years’ were calculated to adjust for differing washout durations. The results obtained include findings that the percentage of patients relapsing in U.S. studies was slightly lower (37.9%) than in non-U.S. studies (46%); the percentage of patients dropping out in U.S. studies (10.5%) was higher than in non-U.S. studies (7.6%); known location of dropout patients in U.S. studies was 1.7%, compared to 2.6% in non-U.S. studies. The most interesting finding was that no suicides were reported in U.S. studies, compared to 0.6% of patients reported in British studies. Some U.S. studies used ‘challenge doses’, such as amphetamines or L-dopa; no non-U.S. studies reported their use. Compared to U.S. studies, those by non-U.S., and particularly British, researchers appeared to report adverse events in their studies. ‘Challenge’ drugs were not used; suicides were reported. It is estimated that the probability that no patients suicided who participated in the U.S. is small—one in 500.     

The role of information technology in building public administration theory

Information technology, that assortment of technology that enables the conversion of data into information, has had an enormous impact on the field of public administration and its theoretical foundation. This article explores five of them. It begins with a discussion of one of the primary impacts of information technology on public administration theory: the development of systems theory and its descendants including the study of complex systems, chaos, and complexity theory. The importance of information technology in decision-making is explored next. Does information technology free us from the limits of bounded rationality or are we simply overwhelmed by the volume of information available via new sources, such as the Internet and the World Wide Web? The third role examined is the use of information technology as a research tool to make previously intractable problems solvable. Computer capability has enormously advanced the theoretical underpinnings of public administration. Fourth, the significance of information technology as a change agent that calls for revision of other theoretical postulates is investigated. As information technology has diffused into public organizations, how has it called into question what we previously thought about the foundation of bureaucracy? Finally, learning by doing and the manner through which practice informs theory is considered.     

LONGITUDINAL STUDY OF PROCRASTINATION, PERFORMANCE, STRESS, AND HEALTH:

Abstract— Procrastination is variously described as harmful, innocuous, or even benefical. Two longitudinal studies examined procrastination among students. Procrastinators reported lower stress and less illness than nonprocrastinators early in the semester, but they reported higher stress and more illness late in the term, and overall they were sicker. Procrastination thus appears to be a self-defeating behavior pattern marked by short-term benefits and long-term costs.     

Modifying Beliefs and Attitudes to Exceeding the Speed Limit: An Intervention Study Based on the Theory of Planned Behavior1

This study builds on previous theory of planned behavior (TPB) studies in which we identified the beliefs and values which predict intention to commit driving violations. Four short experimental videos were developed in order to assess the effectiveness of an intervention grounded in the TPB. Three of the videos featured the major constructs of the TPB model. The fourth video featured anticipated regret, an addition to the TPB model which had previously been shown to add significantly to its predictive performance (Parker, Manstead, & Stradling, 1995). Results indicated that two of the videos brought about statistically significant belief changes with respect to scores on TPB items, and significant changes in general attitudes toward speeding. Discussion centers on the problems encountered in operationalizing the TPB constructs and on the potential of theory-based interventions to induce attitude change.