text: Even bluetooth devices shouldnt be used while driving. The brain tends to use a lot of its visual processing abilities. Talking on the phone may seem to need the use of only your ears, but your ears send a signal to a part of your brain that creates images which is why when your talking on the phone you picture that person in your mind. For example someone asks you a question over the phone, like where did you put the tape? You'll imagine the last place you put it.