There's ample proof that "multitasking" is counterproductive, stressful, and can in many instances produce tragic results (i.e., texting while operating a train!?!) Recently in my city a baby died because the father received an upsetting call on his cell phone while driving. He forgot he was supposed to drop the baby off at daycare (not a usual part of his routine), drove to work, was still on the phone call as he got out of the car and walked to his office. He remembered the baby in the car 6 hours later, but it was too late. His life and his marriage will never be the same - all because he HAD to answer that phone call.
HOWEVER, try to convince anyone in management of this fact. There is such pressure to "do more with less" by multitasking. Five years ago I left a stressful accounting job primarily because the pressure to multitask had an adverse effect on both my job performance and my health and had robbed me of all the joy my work had given me. I took a lower-paying, less stressful job with wonderful, positive retail employer, but as the economy has degraded, I see the same faulty reasoning beginning to tempt a previously sensible, reasonable employer. Employees who were happy, productive, creative people are now unhappy, stressed, having more accidents, taking more unscheduled days off (sickness, sick-of-it-ness, etc.)
How do we get off this slippery slope before we destroy ourselves?