[oldE]

aigel,

I confess fifteen years ago, I was one of those guys who drove while on the cel. Yes it was hands free.
At the time I didn't realize the danger, until one day I realized I had just driven by a flagman and was in the middle of a construction zone. I had been on the phone to a client.

It was a few months later when I was talking to my niece who had been part of the research team that had done the studies with the MRI.

When you are talking to someone who is physically present, you are receiving visual clues from that person which helps your mind evaluate what they are saying. If you are carrying on a conversation with a person not present, part of your brain is engaged trying to make up for the loss of visual data. That is the same part of the brain which feeds the decision making areas data on our surroundings, (such as flagmen, a pedestrian on the crosswalk, etc.).

It is the time spent disengaging from one mental activity to get the situational awreness to the decision making part of the brain that causes the problem.

A few years ago, I watched a demonstration of young people invited to go through a driving game. First they were allowed to drive though the course of city streets. Then they were engaged in a conversation with someone 'off stage' on a cel. Even though they were driving the same course, the errors/accidents/collisions were sobering. These were kids who grew up with this stuff, but their brains had not adapted to the multi-tasking.

Best
Les