Stability and skill in driving

Two experiments addressed the relation between postural stability, perceptual sensitivity, and stability of driving performance. A vehicle was fitted with differential GPS for measuring position and speed, position sensors for measuring brake and accelerator depression, force transducers for measuring door, console and footrest bracing forces, and an accelerometer for measuring the 3D accelerations of the vehicle. In Experiment 1, we investigated whether the initiation of deceleration and the control of braking might be due to sensitivity to the perceptual variable tau, which specifies time-to-contact (TTC), and in particular, whether its first derivative, tau-dot, is used to maintain a constant deceleration profile. Using both untrained experienced drivers (EDs) and trained driving instructors from the Holden Performance Driving Centre (HPDC), results confirmed that, regardless of skill level, tau-dot was maintained at a value close to 0.5 and, as predicted by Lee [Perception 5 (1976) 437], braking was initiated when TTC approximately 5 s. In Experiment 2, we wished to quantify the purported differences in driving behaviour between EDs and HPDC instructors during a variety of everyday manoeuvres. Results indicated that instructors utilised a different cornering trajectory, a different emergency braking strategy, and were able to perform a high-speed swerve and recovery task more effectively than the EDs. In general, the instructors applied greater bracing forces using the door and console compared with EDs. The instructors also applied greater footrest forces during emergency braking than did the EDs. The greater use of bracing by instructor drivers to resist g-forces represents a strategy of active stabilisation that enhances both postural stability, as well as overall stability and consistency of driving performance. Results are discussed with regard to the dynamics of perceptual-motor coordination, and how increased stability might improve sensitivity to relevant perceptual information. We conclude that driver-training programmes that focus on increasing driver stability (as a pre-requisite for increased control) show great promise as a means to improving one's attention during driving, and hence have the potential to dramatically improve road safety in general.     

The Role of the Family in Childhood Obsessive–Compulsive Disorder

While obsessive–compulsive disorder is widely recognized to have a strong genetic component, psychosocial factors are also acknowledged to be important. The primary focus of this paper is on familial factors associated with OCD in children and adolescents. It explores the family context as a possible risk factor in the development and maintenance of the disorder, including parental modeling, expressed emotion, parenting style, and family accommodation of the child's symptoms. The involvement of the family in the treatment of the disorder is also reviewed. Finally, future directions for research investigating familial factors in childhood OCD are presented.     

Functional fixedness in a technologically sparse culture

Problem solving can be inefficient when the solution requires subjects to generate an atypical function for an object and the object's typical function has been primed. Subjects become "fixed" on the design function of the object, and problem solving suffers relative to control conditions in which the object's function is not demonstrated. In the current study, such functional fixedness was demonstrated in a sample of adolescents (mean age of 16 years) among the Shuar of Ecuadorian Amazonia, whose technologically sparse culture provides limited access to large numbers of artifacts with highly specialized functions. This result suggests that design function may universally be the core property of artifact concepts in human semantic memory.     

The ‘Medical Body’ As Philosophy's Arena

Medicine, as Byron Good argues, reconstitutes thehuman body of our daily experience as a medical body,unfamiliar outside medicine. This reconstitution can be seen intwo ways: (i) as a salutary reminder of the extent to which thereality even of the human body is constructed; and (ii) as anarena for what Stephen Toulmin distinguishes as theintersection of natural science and history, in which many ofphilosophy's traditional (and traditionally abstract) questionsare given concrete and urgent form.This paper begins by examining a number of dualities between themedical body and the body familiar in daily experience. Toulmin's epistemological analysis of clinical medicine ascombining both universal and existential knowledge is thenconsidered. Their expression, in terms of attention,respectively, to natural science and to personal history, isexplored through the epistemological contrasts between themedical body and the familiar body, noting the traditionalphilosophical questions which they in turn illustrate.     

The Reduction of Adverse Impact in an Employment Setting Using a Short-Term Memory Test

Research suggests that less adverse impact should result from the use of employment tests assessing memory abilities than is obtained from tests assessing cognitive abilities. To test the application of this principle, a Short-Term Memory test and a Reading Comprehension test were administered as part of a selection battery for entry level police. Subjects were 1423 police officer applicants for a Midwestern city in the U.S. The results for the overall sample showed a smaller standardized difference between the scores of Blacks and Whites on the Short-Term Memory test than on the Reading Comprehension test, a difference which was further reduced when a subsample of Blacks and Whites was created which had been matched on gender, years of education and age.     

The distribution postulate in Bohm's theory

On Bohm's formulation of quantum mechanics particles always have determinate positions and follow continuous trajectories. Bohm's theory, however, requires a postulate that says that particles are initially distributed in a special way: particles are randomly distributed so that the probability of their positions being represented by a point in any regionR in configuration space is equal to the square of the wave-function integrated overR. If the distribution postulate were false, then the theory would generally fail to make the right statistical predictions. Further, if it were false, then there would at least in principle be situations where a particle would approach an eigenstate of having one position but in fact always be somewhere very different. Indeed, we will see how this might happen even if the distribution postulate were true. This will help to show how loose the connection is between the wave-function and the positions of particles in Bohm's theory and what the precise role of the distribution postulate is. Finally, we will briefly consider two attempts to formulate a version of Bohm's theory without the distribution postulate.