Brain research indicates that you can have several motor programs running at the same time. (Your Creative Brain by Shelley Carson, 2000) so you can steer your car, talk to passengers and adjust your rear view mirror simultaneously. Unfortunately you can only focus your conscious mental attention to one of these things at a time. You can multitask physically, but not mentally. What you are really doing is switching your attention rapidly from one task to another. When you physically multitask at work, you may feel you are more effectively using your time. But both your efficiency and effectiveness will decrease. We think sequentially so we should work sequentially.
by Harold Taylor