An interview with Clifford Nass on how multitasking doesn’t really work.
What people call multitasking is really task-switching. When we consciously do something, our attention is placed there (even if we’re not fully aware of that). And when we consciously do two things at once, our attention is switching rapidly between them. I specify consciously to exclude involuntary activities such as breathing or digestion. When it comes to intellectual activity, that switching has a cost and it degrades the quality of all the activities being juggled.