§ 3. Attention. — Perceptual activity can only fulfil itself by the cooperation of a series of external conditions which supply in turn occasions for its further development. Now, if these external occasions are to be utilised in an effective manner, the animal cannot remain purely passive in regard to them. On the contrary, it must meet them halfway by watching for them, and by keeping itself in readiness to act in an appropriate way when they occur. Thus perceptual activity is essentially characterised by attention.* Attention is constantly directed towards the external conditions which are relevant to the progress of the action so as to utilise them. The activity is a train of distinct movements guided by a corresponding train of distinct percepts. Just as the successive movements express the development of one continuous conation, so the distinct percepts are parts of a continuous train in which each sets the mind in an attitude of preparation for the next. Such a train is the analogue on the perceptual level of what, on the ideational,+ we call a train of thought. Consider even such a simple act as the chicken pecking, it may be for the first time. The pecking is not an indeterminate pecking in any direction; it is a pecking at a certain object in a given direction and at a given distance. The act of pecking receives its determinateness from the previous act of seeing, of attentively fixing the eye on the object. Conversely, the tendency to peck guides and controls the act of seeing. It is because the animal is about to peck, or is engaged in pecking, that it keeps its eye on the object; and it is because it keeps its eye on the object that it is enabled to peck in a purposeful manner. This mutual guidance lasts till the moment of seizure, determining this act also, and bringing it within the same total coordination.

* See bk. i., ch. i., p. 65.                        + See note, p. 249.

Attention is always in some manner expectant or prospective. So far as we already know a thing sufficiently for our purpose, the work of attention is already accomplished. The direction of thought, whether perceptual or ideational, coincides with the direction of conation, — of appetency or aversion; conation is always pressing forward towards its end; hence attention, which is nothing but conation defining itself in cognition, and so guiding itself by means of cognition, must also constantly be directed forward beyond the "ignorant present," to meet what is to come. To attend is always to watch, to await, to be on the alert. When we take a light to lighten our path through a dark place, we use it to make out whither we are going, not where we have already arrived. It is to guide our future steps, not the steps we have already taken. Now if we care to use a bold metaphor, we may say that attention is the light used by conation to make out its path. Only we must remember that attention is no external illumination, but is simply identical with conation considered in its cognitive aspect. Trains of perceptual activity are marked throughout their course by this mental prospectiveness. Its external sign is the preadaptation of the senseorgans to receive impressions, and the preadjustment of the body in readiness to act when the opportunity presents itself. The cat lying in wait for the mouse or bird is a sufficient example. The sight and smell of the mousehole, we may suppose, set it in action. Eye and ear are adjusted so as to catch coming impressions, the appearance of the mouse or any sound it makes; the muscles of the body are in a state of tension in preparation for a spring, or other appropriate action. But the action is suppressed and postponed until the occasion for it emerges. Perhaps a doubt may be raised whether such behaviour can be purely perceptual. Does it not of necessity involve acquired ideas and association of ideas? We may take another instance, in which this objection can hardly be urged. A crab or flatfish at the bottom of the sea covers itself with sand, protruding only its stalked eye. With this it keeps restlessly spying in all directions. On the approach of an enemy, the eye is rapidly withdrawn and hidden in the sand. On the appearance of prey, the eye follows its motions. When the prey is near enough, the observant animal darts swiftly up and seizes it. It can scarcely be maintained that this characteristic behaviour is acquired by association of any kind, to say nothing of association of ideas. If the flatfish or crab had to learn to look out for prey, where would its instruction come from? It would certainly have a poor chance of survival. The attentive attitude is frequently found in the very first performance of an instinctive activity.