New Research Shows Why Cell Phones and Driving a Dangerous Mix

A recent study looked at what happens when the brain attempts to juggle two tasks, with experiments that apply to cell-phones and driving. It explained why the habit is so distracting and potentially perilous. Statistics for 2007 from the National Highway Traffic and Safety Administration show 73 percent of drivers use their cell phone behind the wheel despite a wealth of studies that highlight the dangers. The findings from the new study might not curb the habit, but could lead to ergonomic design modifications in vehicles that reduce the impact of the distraction.

A University of South Carolina (USC) news release on May 23 reported that research by Dr. Amit Almor, Associate Professor of Psychology at USC, provides a better understanding of why language – talking and listening, including on a cell phone – interferes with visual tasks, such as driving. The study was published recently in the journal, Experimental Psychology.

In one experiment, participants were required to detect visual shapes on a monitor. A second experiment required participants to use a computer mouse to track a fast-moving target on the screen. In both experiments, participants performed the visual task while listening to prerecorded narratives and responding to the narratives.

Professor Almor found that planning to speak and speaking put far more demands on the brain’s resources than listening. He said the study measured the attention level of 47 subjects and found that they were four times more distracted while preparing to speak or speaking than when they were listening. "People can tune in or out as needed when listening," he added.

In both experiments, the professor placed the participants in a circular, surround-sound environment in which the speakers were hidden and the voice shifted from the front, rear or either side. He found that participants could complete the visual task in front of them more easily when the projected voice also was in front. This effect, while not so strong as the difference between preparing to speak or speaking and listening, suggests that simultaneously performing a language task and a visual task is easier when the tasks are in the same space physically and cognitively.

The researcher calls the finding "very strong" and expects it to be even stronger in actual, interactive conversation. He and Tim Boiteau, a graduate student in linguistics, have repeated the experiment using 20 pairs of friends who engaged in real conversation while completing visual tasks. Those results are being compiled this summer.

"I anticipate the effect to be even stronger and more dynamic because, in conversation, people have the urge to contribute," said Professor Almor. "In conversation, we compete with the other person. I suspect that the greater the urge to speak, the greater the distraction from the visual task."

"Either people are used to face-to-face communication or, when they engage in a language task, they create a mental representation in their mind and place the voice somewhere in space," the professor said. "In this case, that space is in front of them, which suggests that it may be easier to have all things that require attention occupy the same space." He anticipates that the finding may be useful in the development of new technologies. In the case of a car, an internal speaker phone could project a speaker’s voice from the front so that it occupies the same place as the visual task of driving.

Source: University of South Carolina