The perception of briefly exposed point-sources of light

Point-sources of light (dots) were exposed for 10 to 50 msec, before five dark-adapted subjects in a dimly illuminated room. During voluntary fixation with one eye, the target was exposed some 10° on the nasal side of the optic axis. The intensity X duration of all targets was 2 X threshold and they consisted of either a single dot, or a pair of dots separated by a distance that was less than that required for two-point discrimination. In two-thirds of trials both the single-dot and the two-dot targets were perceived as short thin lines of various orientation. Although individual percepts were unpredictable, there was a preferred or most likely orientation for responses to the single-dot target; this was near to the horizontal for all five subjects. There was no significant difference between the preferred orientations for single-dot targets tested at sites more than 1° apart in the visual field. When two single-dot targets, separated by about 1°, were exposed simultaneously, the orientations of the perceived lines sometimes differed by as much as 80°; occasionally, one target was reported as a dot while the other was seen as a thin line. If the single-dot was briefly exposed between two continuously visible and parallel straight lines, the target usually appeared as a thin line, parallel to the framing lines. Some of these results appear to be consistent with the hypothesis that the human visual cortex, like that of the cat and monkey, contains neurones that are orientation specific.     

Youth Suicide Prevention: A Survey and Analysis of Policies and Efforts in the 50 States

State-level initiatives directed at youth suicide prevention since 1980 were analyzed. During 1992 and 1996, each governor was surveyed regarding his or her state's efforts in youth suicide prevention. Questions pertained to legislation, a mandated or recommended school-based suicide prevention curriculum, funding, a special advisory council, a state plan, the development and dissemination of materials, and assessment. Several states sent examples of their prevention activities, which were reviewed to determine the extent to which they represent conceptually and/or empirically grounded preventive intervention strategies. The number of suicides, suicide rates, and percentage change in rate for youth 15–19 years old were reported by state for the periods 1979–1981 and 1992–1994. The results of a repeated measures 2 × 5 ANOVA revealed that while changes in suicide rates over time were statistically significant, there was no relation between these changes and any of the variables studied. Suggestions for future research on state-level initiatives are presented.     

Social-cognitive antecedents of hand washing: Action control bridges the planning–behaviour gap

Objectives. To examine motivational and volitional factors for hand washing in young adults, using the Health Action Process Approach (HAPA) as a theoretical framework.

Design. In a longitudinal design with two measurement points, six weeks apart, university students (N = 440) completed paper-based questionnaires.

Main outcome measures. Prior hand washing frequency, self-efficacy, outcome expectancies, intention and action planning were measured at baseline, and coping planning, action control and hand washing frequency were measured at follow-up.

Results. A theory-based structural equation model was specified. In line with the HAPA, the motivational factors of self-efficacy and outcome expectancies predicted intention, whereas the volitional factors of planning and action control mediated between intention and changes in hand washing frequency. Action control was confirmed as the most proximal factor on hand washing behaviour, thus representing a bridge of the planning–behaviour gap.

Conclusions. Both motivational and volitional processes are important to consider in the improvement of hand hygiene practices. Moreover, the statistically significant effects for planning and action control illustrate the importance of these key self-regulatory factors in the prediction of hand hygiene. The current study highlights the importance of adopting models that account for motivational and volitional factors to better understand hand washing behaviour.