"The ability to do one thing on autopilot while doing something else is referred to as automaticity. While experienced drivers can hold conversations and listen to the radio while driving, novice drivers cannot. Indeed, many new drivers turn off the radio and ask passengers not to talk to them. They also don’t make phone calls or try to send text messages.
Automaticity does not mean that distractions – while driving or otherwise – do not have an impact. Brain scans by neuroscientists studying this issue have shown that the brain has difficulty paying attention to sights and sounds at the same time. If the brain is focused on a visual task, its ability to handle an auditory task decreases markedly, and vice versa."