There is an interesting quote attributed to Lord Chesterfield “There is time enough for everything in the course of the day, if you do but one thing at once, but there is not time enough in the year, if you will do two things at a time ... This steady and undissipated attention to one object, is a sure mark of a superior genius; as hurry, bustle, and agitation, are the never-failing symptoms of a weak and frivolous mind.”
It is used as a "hook" in an interesting article by Christine Rosen in The New Atlantis, called "The Myth of Multi-tasking". She refers to many recent studies that point out why trying to multi-task does not seem to be a good idea. However, I found most interesting her reference to William James, who, she says differentiated in his Principles of Psychology of 1890 between “sensorial attention,” “intellectual attention,” “passive attention,” and the “gray chaotic indiscriminateness” of most people.
I looked it up. It's a bit more complicated. First, James claims uncontroversially that attention "implies withdrawal from some things in order to deal effectively with others, and is a condition which has a real opposite in the confused, dazed, scatterbrained state which in French is called distraction, and Zerstreutheit in German, and he then goes on to differentiates between "various ways" of dividing attention, namely between
a) "Objects of sense (sensorial attention); or to
b) Ideal or represented objects (intellectual attention)."
finding that it is either:
c) "Immediate; or
immediate, when the topic or stimulus is interesting in itself, without relation to anything else; derived, when it owes its interest to association with some other immediately interesting thing. What I call derived attention has been named 'apperceptive' attention."
It must further be considered as either
e) "Passive, reflex, non-voluntary, effortless; or
f) Active and voluntary."
After some discussion, he claims rather controversially that "each of us literally chooses, by his ways of attending to things, what sort of a universe he shall appear to himself to inhabit." But in the next section he asks whether voluntary attention is an effect or a cause ("resultant or force"). His answer is twofold (i) psychology is unable to tell, and (ii) philosophy (or metaphysics) may decide. His decision is that it is attention is a (spiritual) force or cause. But he admits that it is just as reasonable to suppose attention is caused by other factors.
Applied to multi-tasking, James would say (on insufficient empirical evidence) that it the mind that decides what to attend to and that we can engage or disengage in multi-tasking. Others might argue (on insufficient empirical evidence) that it is indeed impossible for the mind to so engage or disengage all by itself. It's ultimately a metaphysical question. When we say that "each of us literally chooses, by his ways of attending to things, what sort of a universe he shall appear to himself to inhabit," we leave the realm of empirical evidence.
And this, of course, has consequences for the tools we use in note-taking, thinking, and writing. Mark Pilgrim has presented a spirited argument against "the latest fad of full-screen 'writing-focused' text editors" in Wrongroom. He does not explicitly argue that they do not work as causes that narrow our focus, but implicit in his argument is the claim that focus or attention depends on the person who uses a text processor, and that it is therefore frivolous to punish or limit the instrument of writing for a failure that resides only in the writer. More than a hundred of comments contradict his post.
As always, it's a bit more complicated, however. And perhaps it still is ultimately a "metaphysical" question.
1. See the Project Gutenberg edition of the Letters to His Son , Letter IX, London, April 14, O. S. 1747). It's interesting (at least to me) that the quote continues: "When you read Horace, attend to the justness of his thoughts, the happiness of his diction, and the beauty of his poetry; and do not think of Puffendorf de Homine el Cive; and, when you are reading Puffendorf, do not think of Madame de St. Germain; nor of Puffendorf, when you are talking to Madame de St. Germain." The context of this claim is the idea that we need to pursue pleasures as well as studies, and that we should give our undivided attention to each as we pursue them.
2. See William James, Principles of Psychology, Chapter 11: Attention