An Introduction to Psychology / Translated from the Second German Edition

by Wilhelm Max Wundt

Rhythmical rows of beats, because of the arrangement of the successive impressions in them, were excellently suited to determine the total scope of consciousness. But because of this very same quality they can give us little help in solving our second problem. For it is obvious that just that connection between the focus of attention and the wider field of consciousness, that the rhythm of a row of beats causes—this connection makes a clear boundary between these two regions impossible. We notice clearly enough that along with the beat that is directly affecting consciousness a few of the preceding ones also fall within the focus of attention, but how many remains uncertain. The sense of sight obviously offers us more favourable conditions. We must, however, first of all note the fact that the physiological conditions of vision in themselves limit the apprehension of an extended object, not taking into account the psychological boundary of clear perception. The keenest differentiation of impressions is limited to the so-called region of clearest vision, which surrounds the fixation-point. The reader can test this for himself by fixating the middle letter "o" in the following diagram of letters from a distance of about 20-25 cm, while keeping one eye closed.

We can in this position, by directing our attention alone to the outlying parts of the field of vision, still recognise letters, which lie at the sides of our figure, as, for example, the h at the top or the i at the right-hand side. To carry out this experiment a little practice in fixation is required, since in natural vision we are always inclined to direct our line of vision to that point, to which our attention is turned. If, however, we practise letting our attention wander over the different parts of the field of vision while keeping the same fixation-point, it will soon be clear to us that the fixation-point of attention and the fixation-point of the field of vision are by no means identical. They can by practice be separated, and the attention can be directed to a point in indirect vision, i.e. a point lying to this or to that side of the line of vision. From this we see that clear perception in the psychological sense and clear vision in the physiological sense do not necessarily coincide. For example, if we fixate the middle letter o, and at the same time direct our attention to the "n" at the right-hand side, we also perceive clearly the letters that surround n, i.e. f g s i, whereas the letters around o, i.e. h t i n, seem to retreat into the darker field of consciousness. This diagram of letters has been printed so large, that when we look at it from a distance of 20-25 cm. it almost corresponds in scope to the region of clearest vision, taking as a measure for this the recognisability of letters of the size of those printed in this book. We see, therefore, at once from the above-described observations, that the scope of the focus of attention and the region of clearest vision in the physiological sense differ widely from each other. The latter, under the conditions of observation we have chosen, comprises a far wider field than the former. In our figure there are 95 letters: If it were possible simultaneously clearly to perceive in the psychological sense all the objects clearly seen physiologically, then we should be able by fixating the point o to perceive all these letters. This is, however, by no means the case. At one given moment we can differentiate only a few, which surround the fixation-point of attention, whether this coincides with the objective fixation-point of the field of vision, as in ordinary vision, or whether it lies in any way outside of this point owing to a severance of the two fixation-points.

Although these observations as to the simultaneous recognition of haphazardly arranged simple objects, e.g. letters, point decisively to a fairly narrow limitation of the scope of attention, still we cannot give an exact numerical answer by this method as to the size of this scope, as we could by means of our metronome experiments in regard to the scope of consciousness. Still, without any great change and without any complicated apparatus, we can make these visual experiments suffice to answer our question. Our immediate results will, of course, only be valid under the special conditions we set up. For this purpose a great number of such diagrams, with letters arranged in the same manner, must be constructed. The position of the letters in each diagram must be different. Then a fairly large square of white cardboard, with a black point in the middle, is made (as in the figure on p. 19). With this we cover the diagram chosen for the experiment. The observer, who previously must not have seen the diagrams, is told to fixate with one eye the point in the middle, and to keep the other eye closed.

The cover is then taken away rapidly for one moment, and then as rapidly replaced. The rapidity of this procedure must be such that no movement of the eye, or wandering of the attention over the field of vision, can take place, as long as the diagram remains uncovered.[1] Each time we repeat the experiment a new diagram must be chosen, otherwise the individual momentary impression will supplement the preceding ones. If we wish to obtain unambiguous results we must choose conditions which exclude such influences of previous perceptions. Our question will therefore be limited to this: What is the number of simple and new impressions in consciousness that the focus of attention can grasp in one given moment? In reference to this way of stating the question, an objection to our method of experimenting might be raised. It might be objected that a letter is not a simple element of consciousness, and that we ought rather to use simpler objects, e.g. dots. But since these lack all means of differentiation, the carrying out of the experiment would be rendered much more difficult, if not impossible. On the other hand, we must not forget that our familiarity with letters is of the greatest importance. Because of this a letter of ordinary print can be perceived as quickly as a single dot—a fact any one can easily prove for himself by means of observation. Such symbols, because of their characteristic differences, have this advantage, that after a momentary impression they can be easily retained in consciousness, and thus an account of what has been clearly perceived can be given after the experiment. If we carry out the experiments in the manner described, it appears that an unpractised observer can perceive, at most, only 3-4 letters. After a few more experiments this number increases to 6. Of course, as before mentioned, a new diagram must be used in every new experiment. This value 6 cannot be increased by further practice, and it remains the same for different observers. We are therefore entitled to regard it as a constant for attention for the human consciousness.

[1] To carry out such experiments more exactly and more uniformly it is best to make use of the simple apparatus called the tachistoscope. A falling screen exposes the object to sight for a very short time, which can be accurately measured. Still, if this apparatus cannot be procured, the procedure described above suffices. Special practice should be devoted to covering and uncovering the diagram, so that this may be done as rapidly as possible.

This determination of the scope of attention is, however, dependent upon one condition, which is exactly the opposite of that introduced in measuring the scope of consciousness. This latter was only possible by using rows of impressions that were bound together into one complex whole. To measure the scope of attention, on the other hand, we must isolate the separate impressions from each other, so that they form an unarranged multiplicity of elements. This is a difference in conditions which certainly does not only depend upon the fact that in the first case the sense of hearing and in the second case the sense of sight was used. We rather conjecture at the very outset that here the chief influence lay in the psychological conditions, in the first case in the combination of the elements into a whole, and in the second in the isolation of the elements. At once the following question naturally arises: What will happen if we, so to speak, change the rôles of these two senses, if we let impressions, connected together as wholes, work upon the sense of sight, and isolated impressions upon the sense of hearing? In the first case we have simply to combine letters together, so that they form words or sentences. A letter is nothing more than an element that has been artificially taken out of such a natural combination. Now if we carry out with these parts of speech experiments in the same manner as we have described above, we obtain, in fact, an absolutely different result. If we show the observer a word such as this—

Miscellaneousness,

he can read it at once, without being prepared for it and without previous practice. With isolated elements he could at most grasp six, but here, under exactly the same conditions, the scope is extended to seventeen or more elements without the slightest difficulty. It is clear that this is essentially the same phenomenon that we encountered in our experiments on rhythm with the sense of hearing. The conditions of combination are, however, in so far different, as the stimuli for the sense of sight were simultaneous, whereas for the sense of hearing the whole was made up of simple impressions that followed each other. And with this another difference is connected. A word can only be recognised at a momentary glance, if it has been known to us before as a whole, or with compound words, if their chief parts have been familiar to us. Therefore a word of an absolutely unknown language appears as a complex of unarranged letters, and with such a complex our scope is again limited to six isolated elements. With a rhythmical row of beats, on the other hand, it is of no consequence what the form of rhythm is that binds them together, since we can think into such a row whatever rhythmical arrangement we choose, as long as it conforms to the general rhythmical disposition of consciousness, i.e. as long as it does not exceed the maximum of three different accents, as we have previously shown. At the same time this requirement shows us that the differences in apprehending a successive and a simultaneous whole, which appear in our experiments with sight and hearing, are in reality only apparent differences. A musical time that is adequate to our sense of rhythm behaves in exactly the same way as a word or sentence that is adequate to our sense of language. Therefore we may presuppose that in the reading, as in the rhythm experiments, it is not the whole of a complex consisting of many elements that is instantaneously grasped by the attention. Only a limited part of such a word falls within the scope of attention, and from this part the psychical power of combination goes over to those other elements that lie in the wider field of consciousness. In fact there is a well-known phenomenon that gives a striking proof for this combination of the parts of a word or sentence grasped by attention with unclearly perceived elements. It consists in the fact that misprints are so often unnoticed, especially in rapid reading. This would be impossible if we were forced to perceive with our attention equally clearly all the separate elements of a long word or of a sentence in order to be able to read. In fact, in each separate moment there are only a few elements within the focus of attention. From these the threads of psychical combination stretch to the elements unclearly perceived—yes, sometimes even to the impressions only physiologically seen that lie in the regions of indirect vision. Just as in hearing a rhythm, the sound impressions affecting consciousness at the moment are bound to the preceding ones that have retreated into the darker regions of consciousness, and, on the other hand, they are preparing the way for further expected impressions. The chief difference of the two cases lies not so much in the formal relations of the scope of attention and of consciousness, as in the constitution of the elements and their combinations.

Let us now, equipped with the results of our visual experiments, turn our attention again to our metronome experiments. The analogy between the two immediately gives rise to this question: Can we not in our rhythm experiments arrange the conditions so that we may obtain a similar isolation of simple impressions, as was necessary in measuring the scope of attention for the sense of sight? Now in fact such an isolation of single beats arises at once, as soon as we restrain a "hearing into" the beats of any kind of accentuation whatever. Even the simplest rhythm, the 2/8 time, must be avoided. This is not so easy as it appears to be at the first glance, because of the rhythmical disposition of our consciousness and of our whole psycho-physical organisation. Again and again we are inclined to hear into a row of beats following each other at similar intervals, at least the 2/8 time. And yet it is possible to conform to this condition, if the metronome beats do not show any noticeable objective differences. The interval between the beats must be chosen long enough to check any tendency to rhythmical grouping, and yet not too long, so that it may still remain possible to grasp so many beats as one whole. In general an interval of from 1 1/2-2 1/2 seconds will conform to this requirement. With such an interval, after a fair amount of practice, it is possible to change at will from a rhythmical to an unrhythmical or absolutely monotonous perception of the beats. If this is done, and if in exactly the same manner as in the rhythm experiments a number of metronome beats is given, and then after a pause the same or a slightly differing number is given, the observer can clearly perceive the identity or difference of the two rows. If in the first test a row of six beats is given (row A), and in the second a row of nine, it appears in repeating two rows of the same length, that a precise recognition of identity is present with row A, whereas with row B this is impossible. Even with seven or eight beats recognition is very uncertain. We arrive therefore at the same result as in our optical experiments. Six simple impressions form the limit for the scope of attention.