The UK law introduced in 2003 banning the use of handheld mobile phones while driving presupposes that it’s the handling aspect of mobile use that’s dangerous rather than the communication aspect. Now a study by psychologists at the University of Illinois has added to the evidence showing that hands-free phones could be dangerous too.
Dozens of students sat at the wheel of a driving simulator and aimed to maintain their lane position and speed as steadily as possible. While driving, they sometimes had to complete a second task that involved either judging the accuracy of statements about the relative location of two campus buildings (speech comprehension), or they had to repeatedly describe the relative location of different campus buildings (speech production).
When performing either of the secondary tasks, the students were less able to maintain a steady speed or maintain a steady distance behind another vehicle, compared with when they were driving without distraction. The authors said their results support the notion that “it’s the cognitive demands associated with communication via wireless phones, rather than use of the phone itself, that interferes with driving performance”.
Paradoxically, however, the students were better at maintaining their lane position when engaged in the language production task, compared with just driving, or driving and listening. “One interpretation of this result is that better lane maintenance while speaking was due to active prioritisation of lane maintenance in response to the perceived greater difficulty of speaking”, the researchers said.
Kubose, T.T., Bock, K., Dell, G.S., Garnsey, S.M., Kramer, A.F. & Mayhugh, J. (2005). The effects of speech production and speech comprehension on simulated driving performance. Applied Cognitive Psychology, In Press. DOI: 10.1002/acp.1164.