Purpose: The present experiment investigated the role of perceptual, cognitive, and motor abilities in street-crossing behaviour with ageing. Previous research has shown that older pedestrians make many unsafe crossing decisions when cars are approaching at high speeds, and miss many crossing opportunities when car speeds are low. The older subjects seem to ignore information about the speed of the approaching cars and to preferentially use simplifying heuristics based on vehicle distance. The objective of the present study was to better understand the underlying age-related changes that lead to these behaviours, with a specific focus on perceptual factors.
Method: Twenty young (age 20-30), 21 younger-old (age 61-71), and 19 older-old (age 72-83) participants took part in the experiment. All participants individually carried out a simulated street-crossing task and took a battery of functional tests assessing perceptual, cognitive, and motor abilities.
Results: In line with earlier findings, the seniors made a greater number of incorrect crossing decisions, with many risky decisions when the vehicle was approaching at a high speed and many missed opportunities at a low speed. Correlation and regression analyses pointed out several functional performance measures as predictors of the way the pedestrians took or did not take information about vehicle speed into account in their decisions. Processing speed and visual attention abilities were shown to play the most important role in explaining the variance in incorrect decisions: these abilities allowed participants to focus their attention on the relevant speed information and to make timely, correct decisions. Time-to-arrival estimates, which informed the pedestrians about the time available for crossing, were found to be the second most predictive factor. Walking speed, by way of which the pedestrians adapted their crossing pace to the perceived available time, also came into play. Inhibition abilities ended up as the last functional predictor; they allowed the pedestrians to ignore irrelevant information and inhibit automatic but unsuitable responses.
Conclusions: The present study provided a multidimensional explanation of increased gap-selection difficulties with ageing, including a combination of perceptual, cognitive, as well as physical performance declines with increasing age. The findings have implications for improving older pedestrians' safety in terms of speed limits, road design, and training.
© 2011 The College of Optometrists.