One study (…) found that workers took an average of twenty-five minutes to recover from interruptions such as phone calls or answering e-mail and return to their original task.
Estimated cost to the U.S. economy from loss of productivity: $650 billion annually.
[W]e are really talking about attention: the art of paying attention, the ability to shift our attention, and, more broadly, to exercise judgment about what objects are worthy of our attention. People who have achieved great things often credit for their success a finely honed skill for paying attention. When asked about his particular genius, Isaac Newton responded that if he had made any discoveries, it was “owing more to patient attention than to any other talent.” (the New Atlantis)