The haptic recognition of geometrical shapes in congenitally blind and blindfolded adolescents: is there a haptic prototype effect?

BACKGROUND: It has been shown that visual geometrical shape categories (rectangle and triangle) are graded structures organized around a prototype as demonstrated by perception and production tasks in adults as well as in children. The visual prototypical shapes are better recognized than other exemplars of the categories. Their existence could emerge from early exposure to these prototypical shapes that are present in our visual environment. The present study examined the role of visual experience in the existence of prototypical shapes by comparing the haptic recognition of geometrical shapes in congenitally blind and blindfolded adolescents. METHODOLOGY/PRINCIPAL FINDINGS: To determine whether the existence of a prototype effect (higher recognition of prototypical shapes than non prototypical shapes) depended on visual experience, congenitally blind and blindfolded sighted adolescents were asked to recognize in the haptic modality three categories of correct shapes (square, rectangle, triangle) varying in orientation (prototypical/canonical orientation vs. non prototypical/canonical orientation rotated by 45°) among a set of other shapes. A haptic prototype effect was found in the blindfolded sighted whereas no difference between prototypical and non prototypical correct shapes was observed in the congenitally blind. A control experiment using a similar visual recognition task confirmed the existence of a visual prototype effect in a group of sighted adolescents. CONCLUSION/SIGNIFICANCE: These findings show that the prototype effect is not intrinsic to the haptic modality but depends on visual experience. This suggests that the occurrence of visual and haptic prototypical shapes in the recognition of geometrical shape seems to depend on visual exposure to these prototypical shapes existing in our environment.

The impact of the preventive medical message on intention to change behavior.

Clinicians counsel patients to adopt behaviors to reduce health risks. We studied, in the case of coronary artery disease, the impact of those parts of the preventive medical message clinicians can vary. We asked 150 French people (86 aged 20-30, 64 aged 60-80) to rate their intention to adopt a specific behavior-take medication, change their diet, or start exercising-in 64 scenarios, composed of two severities of disease manifestations (angina pectoris or heart attack); four levels of its probability of occurrence (5, 10, 15, or 20%) and the associated time horizon (20, 15, 10, or 5 years, respectively); and two levels of controllability of the risk (entirely under your control or not much you can do to reduce it). We found that all four parts of the message had significant main effects and did not interact with each other. Older participants had greater intention to adopt preventive behavior when the time horizon was short and younger ones when it was long. The only gender effect was that older women were more sensitive to time horizon. The message's parts were combined additively. Participants intended to change behavior even when told this would be of little use. We concluded that clinicians should, when possible, discuss all key parts of the preventive medical message; that they can, however, focus on one without reducing the others' impact; and that, at least for outcomes such as angina and heart attack, they should speak of risk with young patients using a long time horizon, with old patients using a short time horizon.

Acceptability for French people of physician-assisted suicide.

Our aim was to understand better how people judge the acceptability of physician-assisted suicide (PAS). We found that, for people in France of all ages and for elderly people with life-threatening illnesses, acceptability is an additive combination of the number of requests for PAS, the patient's age, the amount of physical suffering, and the degree of curability of the illness, not only when judging for hypothetical patients, but also for their spouses and for themselves. PAS can be highly acceptable to people even when the patient does not satisfy all the criteria of legislation about PAS.