Hands free phones threat on the road

Psychology researchers at the University of Warwick have found hand free mobile phones can severely hinder driver’s visual attention.

They found that having a phone conversation whilst driving can add over five metres to the breaking distance of a car travelling at 60 miles and causes almost twice as many errors amongst drivers.

The researchers carried out experiments where one group of participants were asked to pay attention and respond to disks moving around a computer screen whilst being distracted by a conversation from speaker phones. Another group were not distracted during the experiment.

They found that the average reaction times of those engaging in the hands free telephone conversation were 212 milliseconds slower than those who undertook the task without the simultaneous telephone conversation. This would amount to 5.7 extra metres in a car travelling at 60 miles an hour.

The participants having a phone conversation made 83 per cent more errors than those who were not being distracted.

The researchers also ran tests where participants were asked to listen to words and repeat them back, whilst still completing the visual task. Another group had to listen to words and then create a new word with the last letter of the word they had heard. They found that those participants with the more complicated

task were on average 480 milliseconds slower than those with the simpler task.

This suggests that hands free telephone conversations, which require people to carefully consider the information they hear and then to make complex cognitive choices, negatively affect a driver’s ability to process and act on the visual information that is critical to their driving performance.

The researchers did find that simply listening to a story had no effect reaction times.

The research was led by Dr Melina Kunar, from the University of Warwick’s Department of Psychology and Dr Todd Horowitz from Harvard Medical School.

Dr Kunar commented: “Our research shows that simply using phones hands free is not enough to eliminate significant impacts on a driver’s visual attention.

Generating responses for a conversation competes for the brain’s resources with other activities which simply cannot run in parallel. This leads to a cognitive “bottleneck” developing in the brain, particularly with the more complicated task of word generation.”