One study found that multi-tasking can effectively shave 10 points off our IQs, Peter Bregman writes, slashing productivity by as much as 40% through constant interruptions. He offers insights gathered during one week free of multi-tasking. "Research shows that multi-tasking isn't just inefficient, it's stressful. And I found that to be true," he writes. Bregman suggests setting short deadlines to keep yourself focused and moving.