Having committed something to memory, how do we get it back when we want it? To judge from such simple cases as the animal's performance of a previously learned reaction, all that is necessary is a stimulus previously linked with the response. How, for example, shall we get the cat to turn the door-button, this being an act that the cat has previously learned? Why, we put the cat into the same cage, i.e., we supply the stimulus that has previously given the reaction, and trust to it to give the same reaction again. The learning process has attached this reaction to this stimulus. Now can we say the same regarding material committed to memory by the human subject? Is recall a species of learned reaction that needs only the linked stimulus to arouse it?

If you have learned and still retain a list of numbers or syllables, you can recite it on thinking of it, on hearing words that identify it in your mind, or on being given the first few items in the list as a start. The act of reciting the list became linked, during the learning, with the thought of the list, with words signifying this particular list, and with the first items of the list; therefore, these stimuli can now arouse the reaction of reciting the list. As you advance into the list, reciting it, the parts already recited act as stimuli to keep you going forward. In the same way, if you have memorized Hamlet's soliloquy, this title serves as the stimulus to make you recall the beginning of the speech and that in turn calls up the next part and so on; or, if you have analyzed the speech into an outline, the title calls up the outline and the outline acts as the stimulus to call up the several parts that were attached to the outline in the process of memorization. When one idea calls up another, the first acts as a stimulus and the second is a {355} response previously attached to this stimulus. In general, then, recall is a learned response to a stimulus.

There is an exceptional case, where recall seems to occur without any stimulus. This form of recall goes by the name of perseveration, and a good instance of it is the "running of a tune in the head", shortly after it has been heard. Another instance is the vivid flashing of scenes of the day before the "mind's eye" as one lies in bed before going to sleep. It appears as if the sights or sounds came up of themselves and without any stimulus. Possibly there is some vague stimulus which cannot itself be detected. Only a slight stimulus would be needed, because these recent and vivid experiences are so easily aroused.

Difficulties in recall.

Sometimes recall fails to materialize when we wish it and have good reason for expecting it. We know this person's name, as is proved by the fact that we later recall it, but at the moment we cannot bring it up. We know the answer to this examination question, but in the heat of the examination we give the wrong answer, though afterwards the right answer comes to mind. This seldom happens with thoroughly learned facts, but frequently with facts that are moderately well known. Some sort of inhibition or interference blocks recall.

One type of interference is emotional. Fear may paralyze recall. Anxious self-consciousness, or stage fright, has prevented the recall of many a well-learned speech, and interfered with the skilful performance of many a well-trained act.

Distraction is an interference, since it keeps the stimulus from exerting its full effect. Sometimes the stimulus that is present has been linked with two or more responses, and these get in each other's way; as you will sometimes hear a speaker hesitate and become confused from having two ways {356} of expressing the same thought occur to him at almost the same instant.

Helps in recall.

There are no sure rules for avoiding these intricate interferences; and, in general, recall being a much less manageable process than memorizing, we do not have anything like the same mass of practical information regarding it. One or two suggestions have some value, however.

(1) Give the stimulus a good chance. Look squarely at the person whose name you wish to recall, avoiding doubt as to your ability to recall it; for doubt is itself a distraction. Put yourself back into the time when you formerly used this person's name. In extemporaneous speaking, go ahead confidently, avoid worry and self-consciousness, and, full of your subject, trust to your ideas to recall the words as needed. Once carried away with his subject, a speaker may surprise himself by his own fluency.

(2) Drop the matter for a while, and come back to it afresh. Sometimes, when you cannot at once recall a name, it does no good to keep doggedly hunting, while half an hour later you get it without the least trouble. The explanation of this curious phenomenon is found in interference and the dying out of interference. At your first attempt to recall the name, you simply got on the wrong track, and thus gave this wrong track the "recency" advantage over the right track; but this temporary advantage fades out rapidly with rest and leaves the advantage with the track most used in the past.

The rule to drop a matter when baffled and confused, and take it up again when fresh, can be used in more complex cases than hunting for a name. When, in trying to solve any sort of problem, you find yourself in a rut, about the only escape is to back off, rest up, and make an entirely fresh start.{357}