Distraction is an important topic for consideration in connection with sustained attention. A distraction is a stimulus that attracts attention away from the thing to which we mean to attend. There are always competing stimuli, and the various factors of advantage, especially desire or interest, determine which stimulus shall get attention at any moment.
In the excited insane condition known as "mania" or the "manic state", the patient is excessively distractible. He commences to tell you something, all interest in what he has to say, but, if you pull out your watch while he is talking, he drops his story in the middle of a sentence and shifts to some remark about the watch. He seems to have no impulse persistent enough to hold his thoughts steady. There are contrary insane conditions in which it is almost impossible to distract the patient from his own inner broodings, so much is he absorbed in his own troubles.
Distraction is a favorite topic for experiment in the laboratory. The subject is put to work adding or typewriting, and works for a time in quiet, after which disturbances are introduced. A bell rings, a phonograph record is played, perhaps a perfect bedlam of noise is let loose; with the curious result that the subject, only momentarily distracted, accomplishes more work rather than less. The distraction has acted as a stimulus to greater effort, and by this effort [{260}] is overcame. This does not always happen so in real life, but it shows the possibilities of sustained attention.
There are several ways of overcoming a distraction. First, greater energy may be thrown into the task one is trying to perform. The extra effort is apt to show itself in gritting the teeth, reading or speaking aloud, and similar muscular activity which, while entirely unnecessary for executing the task in hand, helps by keeping the main stream of energy directed into the task instead of toward the distracting stimuli. Effort is necessary when the main task is uninteresting, or when the distraction is specially attractive, or even when the distraction is something new and strange and likely to arouse curiosity. But one may grow accustomed or "adapted" to an oft-recurring distraction, so as to sidetrack it without effort; in other words, a habit of inattention to the distracting stimulus may be formed. There is another, quite different way of overcoming a distraction, which works very well where it can be employed, and that is to couple the distraction to the main task, so as to deal with both together. An example is seen in piano playing. The beginner at the piano likes to play with the right band alone, because striking a note with the left hand distracts him from striking the proper note with the right. But, after practice, he couples the two hands, strikes the bass note of a chord with the left hand while his right strikes the other notes of the same chord, and much prefers two-handed to one-handed playing. In short, to overcome a distraction, you either sidetrack it or else couple it to your main task.
Doing Two Things at Once
The subject of distraction brings to mind the question that is often asked, "Can any one do two things at once?" In this form, the question admits of but one answer, for we [{261}] are always doing at least two things at once, provided we are doing anything else besides breathing. We have no trouble in breathing and walking at the same time, nor in seeing while breathing and walking, nor even in thinking at the same time. But breathing, walking, and seeing are so automatic as to require no attention. The more important question then, is whether we can do two things at once, when each demands careful attention.
The redoubtable Julius Caesar, of happy memory, is said to have been able to dictate at once to several copyists. Now, Caesar's copyists were not stenographers, but wrote in long-hand, so that he could speak much faster than they could write. What he did, accordingly, was undoubtedly to give the first copyist a start on the first letter he wished to send, then turn to the second and give him a start on the second letter, and so on, getting back to the first in time to keep him busy. Quite an intellectual feat, certainly! But not a feat requiring absolutely simultaneous attention to several different matters. In a small way, any one can do something of the same kind. It is not impossible to add columns of numbers while reciting a familiar poem; you get the poem started and then let it run on automatically for a few words while you add a few numbers, switch back to the poem and then back to the adding, and so on. But in all this there is no doing of two things, attentively, at the same instant of time.
You may be able, however, to combine two acts into a single coördinated act, in the way just described under the head of distraction, and give undivided attention to this compound act.
The Span of Attention
Similar to the question whether we can attentively perform more than a single act at a time is the question of [{262}] how many different objects we can attend to at once. The "span of attention" for objects of any given kind is measured by discovering how many such objects can be clearly seen, or heard, or felt, in a single instant of time. Measurement of this "span" is one of the oldest experiments in psychology. Place a number of marbles in a little box, take a single peek into the box and see if you know how many marbles are there. Four or five you can get in a single glance, but with more there you become uncertain.