3/26/2010

A comment to the 3/22/ post asked. “… An "expert" said that when you are driving and receiving information through the phone, your brain goes into something he called sensory overload. Your peripheral vision is severely reduced and you basically are looking straight ahead. I can understand this when actually holding a cell phone to your ear. They did not make a distinction between hands free devices and holding a phone however. So my question is this.....would it be different if you were hands free and talking on the phone or would you still be overloaded. And if this is the case, how does this relate to talking to a passenger? Is that the same dynamic or different? Explain sensory overload.”

Sensory overload is a condition where the senses are strained and to the point it becomes difficult to focus on the task at hand. We commonly experience this situation if, say, we’re talking on the phone and our spouse asks us a question. It’s impossible to carry on the phone conversation and answer, so we pause the conversation long enough to take care of our spouse. Okay, you say, but that’s not the same as driving and talking. Well, yes it is. Can you type a letter while carrying on a conversation? No you can’t. And it doesn’t make any difference if you’re holding the phone or not – concentrating on the conversation at hand detracts from paying attention to driving.

The deceiving thing about driving is that much of the brain’s motor activity is automatic in that the visual information coming into our brain elicits a preprogrammed response, like turning through a curve in the road. This lulls us into believing we can do other things while driving. (I’ve seen drivers putting on makeup while driving 60 mph on the freeway). But the truth is the brain really can only really concentrate on one task at a time. The more you try to multitask, the poorer your performance in any of the tasks.

Driving requires constant vigilance. The more that vigilance that is distracted, the longer the reaction time to an unplanned event and the less we are aware of what’s going on around us. This holds true regardless of whether the conversation is on the phone or with the passenger next to us.