Age Differences in Perceptual Judgments about Potential Collision and Implications for Driving

Abstract

To travel safely, drivers must detect and identify conditions that precipitate collisions. Previous results suggest that judgments about collision are influenced by scene parameters, task constraints, and age. Such studies typically focussed on judgments about when a collision would occur (time to contact). Results indicated that older observers underestimated time to contact more than younger observers; they thought that collisions would occur relatively sooner (Hancock & Manser, 1997; Schiff et al., 1992). However, biases toward underestimation would decrease the risk for accidents (Scialfa et al., 1987). Therefore, the age difference in judgments about time to contact does not seem to be a good candidate to account for the higher accident rate in older drivers. Alternatively, age differences in judgments about whether a collision would occur (potential collision; DeLucia, 1995) may contribute to differential accident rates. Therefore, age differences in such judgments were measured with computer simulations of three-dimensional scenes. When participants reported whether two moving objects would collide with each other, older adults (51-76 years) responded less accurately and more quickly than younger adults (18-23 years). When participants reported whether an approaching object would hit them, mean thresholds were greater for older females compared with younger females. The results indicate that the ability to detect collisions is an important factor to consider in an account of age differences in accident rates. Further research is warranted to determine whether less effective judgments about whether a collision would occur contribute more to the higher rate of traffic accidents and convictions in older drivers than to (mis)estimates of when a collision would occur.