A preliminary evaluation of the effectiveness of a standardized Student Assistance Program.

We examined the effectiveness of Student Assistance Program group counseling. One hundred and forty-four (144) substance using high school seniors completed a questionnaire in 1995 concerning their substance use before and after counseling, their experience in counseling, and the impact of counseling on their substance use. Participants reported significant decreases in substance use and attributed these changes to counseling.

Misperception of time-to-collision by drivers in pedestrian accidents.

The approach of an object can be monitored from its optic flow. More specifically, it has been postulated that time-to-collision at constant velocity is perceived by relating visual angle theta to its rate of change theta, time-to-collision being theta/theta. This hypothesis is reappraised, and an alternative based on the parameters theta and angular acceleration theta is proposed.