In the laboratory we have "exposure apparatus" for displaying a card for a fifth of a second or less, just enough time for a single glance.

Make a number of dots or strokes on the card and see whether the subject knows the number on sight. He can tell four or five, and beyond that makes many mistakes.

Expose letters not making any word and he can read about four at a glance. But if the letters make familiar words, he can read three or four words at a glance. If the words make a familiar phrase, he gets a phrase of several words, containing as many as twenty letters, at a single glance.

Expose a number of little squares of different colors, and a well-trained subject will report correctly as many as five colors, though he cannot reach this number every time.

Summary of the Laws of Attention

Bringing together now what we have learned regarding the higher and more difficult forms of attention, as revealed by sustained attention and work under distraction, by the span of attention and by trying to do two things at once, we find the previously stated three laws of attention further ill.u.s.trated, and a couple of new laws making their appearance.

(1) The _law of selection_ still holds good in these more {263} difficult performances, since only one attentive response is made at the same instant of time. Automatic activities may be simultaneously going on, but any two attentive responses seem to be inconsistent with each other, so that the making of one excludes the other, in accordance with the general law of selection.

What shall we say, however, of reading four disconnected letters at the same time, or of seeing clearly four colors at the same time?

Here, it would seem, several things are separately attended to at once. The several things are similar, and close together, and the responses required are all simple and much alike. Such responses, under such very favorable conditions, are perhaps, then, not inconsistent with each other, so that two, three, or even four such attentive responses may be made at the same time.

(2) The _law of advantage_ holds good, as ill.u.s.trated by the fact that some distractions are harder to resist than others.

(3) The _law of shifting_ holds good, as ill.u.s.trated by the constant movement of attention, even when it is "sustained", and by the alternation between two activities when we are trying to carry them both along simultaneously.

(4) The _law of sustained attention_, or of _tendency_ in attention, is the same old law of tendency that has shown itself repeatedly in earlier chapters. A tendency, when aroused to activity, facilitates responses that are in its line and inhibits others. A tendency is thus a strong factor of advantage, and it limits the shifting of attention.

(5) A new law has come to light, the _law of combination_, which reads as follows: _a single response may be made to two or more stimuli_; or, _two or more stimuli may arouse a single joint response_.

Even though, in accordance with the law of selection, only one attentive response is made at the same time, more than {264} one stimulus may be dealt with by this single attentive response. Groups of four dots are grasped as units, familiar words are grasped as units. Notice that these units are our own units, not external units.

Physically, a row of six dots is as much a unit as a row of four, but we grasp the four as a unit in a way that we cannot apply to the six.

Physically, six letters are as much a unit when they do not form a word as when they do; but we can make a unitary response to the six in the one case and not in the other. The response is a unit, though aroused by a number of separate stimuli.

The law of combination, from its name, is open to a possible misconception, as if we reached out and grasped and combined the stimuli, whereas ordinarily we do nothing to the stimuli, except to see them and recognize them, or in some such way respond to them. The combination is something that happens _in us_; it is our response. If the expression were not so c.u.mbersome, we might more accurately name this law that of "unitary response to a plurality of stimuli".

Sometimes, indeed, we do make an actual motor response to two or more stimuli, as when we strike a chord of several notes on the piano. The law of combination still holds good here, since the movements of the two hands are coordinated into a single act, which is thought of as a unit ("striking a chord"), attended to as a unit, and executed as a unit. Such coordinated movements may be called "higher motor units", and we shall find much to say regarding them when we come to the subject of learned reactions. The law of combination, all in all, will be found later to have extreme importance in learned reactions.

Pa.s.sing now to another side of the study of attention, we shall immediately come across a sixth law to add to our list.

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Attention and Degree of Consciousness

Up to this point, the introspective side of the psychology of attention has not been considered. One of the surest of all introspective observations belongs right here, to the effect that we are more conscious of that to which we are attending than of anything else. Of two stimuli acting at once upon us, we are the more conscious of that one which catches our attention; of two acts that we perform simultaneously, that one is more conscious that is performed attentively.

We need not be entirely unconscious of the act or the stimulus to which we are not attending. We may be dimly conscious of it. There are degrees of consciousness. Suppose, for example, you are looking out of the window while "lost in thought". You are most conscious of the matter of your thoughts, but conscious to a degree of what you see out of the window. Your eyes are focused on some particular object outside, and you are more conscious of this than of other objects seen in indirect vision, though even of these last you are not altogether unconscious. Consciousness shades off from high light to dim background.

The "field of attention" is the maximum or high light of consciousness; it comprises the object under attentive observation, the reaction attentively performed. The "field of consciousness"

includes the field of attention and much besides. It includes objects of which we are vaguely aware, desires active but not clearly formulated, feelings of pleasantness or unpleasantness, of tension, excitement, confidence, etc.

Apparently the field of consciousness shades off gradually into the field of unconscious activity. Some physiological processes go on unconsciously, and very habitual movements may be almost or entirely unconscious. The boundary {266} between what is vaguely conscious and what is entirely unconscious is necessarily very vague itself, but the probability is that the field of consciousness is broader than we usually suspect, and that many activities that we ordinarily think of as unconscious, because we do not observe them at the time nor remember them later, lie really near the margin of the field of consciousness, but inside that field. "Unconscious motives", such as spite or pride often seem to be, are probably vaguely conscious rather than unconscious. We shall return to the fascinating topic of the unconscious at the close of the book.

Degree of consciousness does not always tally with intensity of sensation or energy of muscular action. You may be more conscious of a slight but significant sound than of much louder noises occurring at the same time. You may be more conscious of a delicate finger movement than of a strong contraction of big muscles occurring at the same time. Degree of consciousness goes with degree of mental activity. Of all the reactions we are making at the same time--and usually there are several--the most active in a mental way is the most conscious.

The slight sound arouses intense mental response because it means something of importance--like the faint cry of the baby upstairs, noticed instead of the loud noises of the street. The delicate finger movement aims at some difficult result, while the big muscles may be doing their accustomed work automatically.

It is not always the most efficient mental process that is most conscious; indeed, practising an act makes it both more efficient and less conscious. It is, rather, the less efficient processes that require attention, because they require mental work to keep them going straight.

Our sixth law of attention, emerging from this introspective study, is naturally of a different style from the remainder of the list, which were objectively observed; yet it {267} is no less certain and perhaps no less significant. It may be called:

(6) The _law of degrees of consciousness_, and thus stated: _An attentive response is conscious to a higher degree than any inattentive response made at the same time_. An inattentive response may be dimly conscious or, perhaps, altogether unconscious. The less familiar the response, and the higher it stands in the scale of mental performances, the more attentive it is, and the more conscious.

The Management of Attention

Attentive observation is more trustworthy than inattentive, and also gives more facts. Attentive movement is more accurate than inattentive, and may be quicker as well. Attentive study gives quicker learning than inattentive, and at the same time fixes the facts more durably.

Shall we say, then, "Do everything attentively"? But that is impossible. We sense so many stimuli at once that we could not possibly attend to all of them. We do several things at once, and cannot give attention to them all. A skilful performance consists of many parts, and we cannot possibly give careful attention to all the parts. Attention is necessarily selective, and the best advice is, not simply to "be attentive", but to attend to the right things.

In observation, the best plan is obviously to decide beforehand exactly what needs to be observed, and then to focus attention on this precise point. That is the principle underlying the remarkably sure and keen observation of the scientist. Reading may be called a kind of observation, since the reader is looking for what the author has to tell; and the rule that holds for other observation holds also for reading. That is to say that the reader finds the most when he knows just what he is looking for. We can learn {268} something here from story-reading, which is the most efficient sort of reading, in the sense that you get the point of the story better than that of more serious reading matter, the reason being that attention is always pressing forward in the story, looking for something very definite.

You want to know how the hero gets out of the fix he is in, and you press forward and find out with great certainty and little loss of time. The best readers of serious matter have a similar eagerness to discover what the author has to say; they get the author's question, and press on to find his answer. Such readers are both quick and retentive. The dawdling reader, who simply spends so much time and covers so many pages, in the vague hope that something will stick, does not remember the point because he never got the point, and never got it because he wasn't looking for it.

In skilled movement, or skilled action of any sort, the best rule is to fix attention on the end-result or, if the process is long, on the result that immediately needs to be accomplished. "Keep your eye on the ball" when the end just now to be achieved is. .h.i.tting the ball.

Attention to the details of the process, though necessary in learning a skilled movement, is distracting and confusing after skill has been acquired. The runner does not attend to his legs, but to the goal or, if that is still distant, to the runner just ahead of him.

Theory of Attention

The chief facts to take account of in attempting to form a conception of the brain action in attention are mobility, persistence in spite of mobility, and focusing.

The mobility of attention must mean that brain activities are in constant flux, with nerve currents continually shooting hither and thither and arousing ever fresh groups of neurones; but sustained attention means that a brain {269} activity (representing the desire or interest or reaction-tendency dominant at the time) may persist and limit the range of the mobile activities, by facilitating some of these and inhibiting others.

The "focusing" of mental activity is more difficult to translate into neural terms. The fact to be translated is that, while several mental activities may go on at once, only one occupies the focus of attention. This must mean that, while several brain activities go on at once, one is superior in some way to the rest. The superiority might lie in greater intensity of neurone action, or in greater extent; that is, one brain activity is bigger in some way than any other occurring at the same time--bigger either because the neurones in it are working more energetically or because it includes a larger number of active neurones.

But why should not two equally big brain activities sometimes occur at the same moment, and attention thus be divided? The only promising hypothesis that has been offered to explain the absence of divided attention is that of "neurone drainage", according to which one or the other of two neurone groups, simultaneously aroused to activity, drains off the energy from the other, so putting a quietus on it.

Unfortunately, this hypothesis explains too much, for it would make it impossible for minor brain activities to go on at the same time as the major one, and that would mean that only one thing could be done at a time, and that the field of consciousness was no broader than the field of attention. On the whole, we must admit that we do not know exactly what the focusing of attention can mean in brain terms.

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EXERCISES

1. Outline the chapter, in the form of a number of "laws", putting under each law the chief facts that belong there.

2. See if you can verify, by watching another person's eyes, the statements made on page 250 regarding eye movements.

3. Choose a spot where there is a good deal going on, stay there for five minutes and jot down the things that attract your attention. Cla.s.sify the stimuli under the several "factors of advantage".

4. Mention some stimulus to which you have a habit of attention, and one to which you have a habit of inattention.

5. Close the eyes, and direct attention to the field of cutaneous and kinesthetic sensations. Do sensations emerge of which you are ordinarily only dimly conscious? Does shifting occur?

6. Of the several factors of advantage, which would be most effective in catching another person's attention, and which in holding his attention?

7. How does attention, in a blind person, probably differ from that of a seeing person?