Thus would I answer, in order to secure your attention for the consideration of these apparently insignificant errors made by normal people. At this point, we will question a stranger to psychoanalysis and ask him how he explains these occurrences.
His first answer is sure to be, "Oh, they are not worth an explanation; they are merely slight accidents." What does he mean by this? Does he mean to assert that there are any occurrences so insignificant that they fall out of the causal sequence of things, or that they might just as well be something different from what they are? If any one thus denies the determination of natural phenomena at one such point, he has vitiated the entire scientific viewpoint. One can then point out to him how much more consistent is the religious point of view, when it explicitly asserts that "No sparrow falls from the roof without God's special wish." I imagine our friend will not be willing to follow his first answer to its logical conclusion; he will interrupt and say that if he were to study these things he would probably find an explanation for them. He will say that this is a case of slight functional disturbance, of an inaccurate psychic act whose causal factors can be outlined. A man who otherwise speaks correctly may make a slip of the tonguewhen he is slightly ill or fatigued; when he is excited; when his attention is concentrated on something else. It is easy to prove these statements. Slips of the tongue do really occur with special frequency when one is tired, when one has a headache or when one is indisposed. Forgetting proper names is a very frequent occurrence under these circumstances. Many persons even recognize the imminence of an indisposition by the inability to recall proper names. Often also one mixes up words or objects during excitement, one picks up the wrong things; and the forgetting of projects, as well as the doing of any number of other unintentional acts, becomes conspicuous when one is distracted; in other words, when one's attention is concentrated on other things. A familiar instance of such distraction is the professor in Fliegende Blätter, who takes the wrong hat because he is thinking of the problems which he wishes to treat in his next book. Each of us knows from experience some examples of how one can forget projects which one has planned and promises which one has made, because an experience has intervened which has preoccupied one deeply.
This seems both comprehensible and irrefutable. It is perhaps not very interesting, not as we expected it to be. But let us consider this explanation of errors. The conditions which have been cited as necessary for the occurrence of these phenomena are not all identical. Illness and disorders of circulation afford a physiological basis. Excitement, fatigue and distraction are conditions of a different sort, which one could designate as psychophysiological. About these latter it is easy to theorize. Fatigue, as well as distraction, and perhaps also general excitement, cause a scattering of the attention which can result in the act in progress not receiving sufficient attention. This act can then be more easily interrupted than usual, and may be inexactly carried out. A slight illness, or a change in the distribution of blood in the central organ of the nervous system, can have the same effect, inasmuch as it influences the determining factor, the distribution of attention, in a similar way. In all cases, therefore, it is a question of the effects of a distraction of the attention, caused either by organic or psychic factors.
But this does not seem to yield much of interest for our psychoanalytic investigation. We might even feel tempted to give up the subject. To be sure, when we look more closely we find that not everything squares with this attention theory of psychological errors, or that at any rate not everything can be directly deduced from it. We find that such errors and such forgetting occur even when people are not fatigued, distracted or excited, but are in every way in their normal state; unless, in consequence of these errors, one were to attribute to them an excitement which they themselves do not acknowledge. Nor is the mechanism so simple that the success of an act is assured by an intensification of the attention bestowed upon it, and endangered by its diminution. There are many acts which one performs in a purely automatic way and with very little attention, but which are yet carried out quite successfully. The pedestrian who scarcely knows where he is going, nevertheless keeps to the right road and stops at his destination without having gone astray. At least, this is the rule. The practiced pianist touches the right keys without thinking of them. He may, of course, also make an occasional mistake, but if automatic playing increased the likelihood of errors, it would be just the virtuoso whose playing has, through practice, become most automatic, who would be the most exposed to this danger. Yet we see, on the contrary, that many acts are most successfully carried out when they are not the objects of particularly concentrated attention, and that the mistakes occur just at the point where one is most anxious to be accuratewhere a distraction of the necessary attention is therefore surely least permissible. One could then say that this is the effect of the "excitement," but we do not understand why the excitement does not intensify the concentration of attention on the goal that is so much desired. If in an important speech or discussion anyone says the opposite of what he means, then that can hardly be explained according to the psychophysiological or the attention theories.