to make a slip of the tongue; often one fails to hear his own slip, though never that of another. Tongue slips are in a certain sense infectious; it is not at all easy to discuss tongue slips without falling into slips of the tongue oneself. The most trifling forms of tongue slips are just the ones which have no particular illumination to throw on the hidden psychic processes, but are nevertheless not difficult to penetrate in their motivation. If, for example, anyone pronounces a long vowel as a short, in consequence of an interference no matter how motivated, he will for that reason soon after lengthen a short vowel and commit a new slip in compensation for the earlier one. The same thing occurs when one has pronounced a double vowel unclearly and hastily; for example, an “eu” or an “oi” as “ei.” The speaker tries to correct it by changing a subsequent “ei” or “eu” to “oi.” In this conduct the determining factor seems to be a certain consideration for the hearer, who is not to think that it is immaterial to the speaker how he treats his mother tongue. The second, compensating distortion actually has the purpose of making the hearer conscious of the first, and of assuring him that it also did not escape the speaker. The most frequent and most trifling cases of slips consist in the contractions and foresoundings which show themselves in inconspicuous parts of speech. One’s tongue slips in a longer speech to such an extent that the last word of the intended speech is said too soon. That gives the impression of a certain impatience to be finished with the sentence and gives proof in general of a certain resistance to communicating this sentence or speech as a whole. Thus we come to borderline cases in which the differences between the psychoanalytic and the common physiological conception of tongue slips are blended. We assume that in these cases there is a tendency which interferes with the intention of the speech. But it can only announce that it is present, and not what its own intention is. The interference which it occasions then follows some sound influences or associative relationship, and may be considered as a distraction of attention from the intended speech. But neither this disturbance of attention nor the associative tendency which has been activated, strikes the essence of the process. This hints, however, at the existence of an intention which interferes with the purposed speech, an intention whose nature cannot (as is possible in all the more pronounced cases of tongue slips) this time be guessed from its effects.
Slips of the pen, to which I now turn, are in agreement with those of the tongue to the extent that we need expect to gain no new points of view from them. Perhaps we will be content with a small gleaning. Those very common little slips of the pen — contractions, anticipations of later words, particularly of the last words — again point to a general distaste for writing, and to an impatience to be done; the pronounced effects of pen slips permit the nature and purpose of the interfering tendency to be recognized. One knows in general that if one finds a slip of the pen in a letter everything was not as usual with the writer. What was the matter one cannot always establish. The pen slip is frequently as little noticed by the person who makes it as the tongue slip. The following observation is striking: There are some persons who have the habit of always rereading a letter they have written before sending it. Others do not do so. But if the latter make an exception and reread the letter, they always have the opportunity of finding and correcting a conspicuous pen slip. How can that be explained? This looks as if these persons knew that they had made a slip of the pen while writing the letter. Shall we really believe that such is the case?
There is an interesting problem linked with the practical significance of the pen slip. You may recall the case of the murderer H., who made a practice of obtaining cultures of the most dangerous disease germs from scientific institutions, by pretending to be a bacteriologist, and who used these cultures to get his close relatives out of the way in this most modern fashion. This man once complained to the authorities of such an institution about the ineffectiveness of the culture which had been sent to him, but committed a pen slip and instead of the words, “in my attempts on mice and guinea pigs,” was plainly written, “in my attempts on people.”20 This slip even attracted the attention of the doctors at the institution, but so far as I know, they drew no conclusion from it. Now what do you think? Might not the doctors better have accepted the slip as a confession and instituted an investigation through which the murderer’s handiwork would have been blocked in time? In this case was not ignorance of our conception of errors to blame for an omission of practical importance? Well, I am inclined to think that such a slip would surely seem very suspicious to me, but a fact of great importance stands in the way of its utilization as a confession. The thing is not so simple. The pen slip is surely an indication, but by itself it would not have been sufficient to instigate an investigation. That the man is preoccupied with the thought of infecting human beings, the slip certainly does betray, but it does not make it possible to decide whether this thought has the value of a clear plan of injury or merely of a phantasy having no practical consequence. It is even possible that the person who made such a slip will deny this phantasy with the best subjective justification and will reject it as something entirely alien to him. Later, when we give our attention to the difference between psychic and material reality, you will understand these possibilities even better. Yet this is again a case in which an error later attained unsuspected significance.
In misreading, we encounter a psychic situation which is clearly differentiated from that of the tongue slips or pen slips. The one of the two rival tendencies is here replaced by a sensory stimulus and perhaps for that reason is less resistant. What one is reading is not a production of one’s own psychic activity, as is something which one intends to write. In a large majority of cases, therefore, the misreading consists in a complete substitution. One substitutes another word for the word to be read, and there need be no connection in meaning between the text and the product of the misreading. In general, the slip is based upon a word resemblance. Lichtenberg’s example of reading “Agamemnon” for “angenommen”21 is the best of this group. If one wishes to discover the interfering tendency which causes the misreading, one may completely ignore the misread text and can begin the analytic investigation with the two questions: What is the first idea that occurs in free association to the product of the misreading, and, in what situation did the misreading occur? Now and then a knowledge of the latter suffices by itself to explain the misreading. Take, for example, the individual who, distressed by certain needs, wanders about in a strange city and reads the word “Closethaus” on a large sign on the first floor of a house. He has just time to be surprised at the fact that the sign has been nailed so high up when he discovers that, accurately observed, the sign reads “Corset-haus.” In other cases the misreadings which are independent of the text require a penetrating analysis which cannot be accomplished without practice and confidence in the psychoanalytic technique. But generally it is not a matter of much difficulty to obtain the elucidation of a misreading. The substituted word, as in the example, “Agamemnon,” betrays without more ado the thought sequence from which the interference results. In war times, for instance, it is very common for one to read into everything which contains a similar word structure, the names of the cities, generals and military expressions which are constantly buzzing around us. In this way, whatever interests and preoccupies one puts itself in the place of that which is foreign or uninteresting. The after-effects of thoughts blur the new perceptions.
There are other types of misreadings, in which the text itself arouses the disturbing tendency, by means of which it is then most often changed into its opposite. One reads something which is undesired; analysis then convinces one that an intensive wish to reject what has been read should be made responsible for the alteration.
In the first mentioned and more frequent cases of misreading, two factors are neglected to which we gave an important role in the mechanism of errors: the conflict of two tendencies and the suppression of one which then indemnifies itself by producing the error. Not that anything like the opposite occurs in misreading, but the importunity of the idea content which leads to misreading is nevertheless much more conspicuous than the suppression to which the latter may previously have been subjected. Just these two factors are most tangibly apparent in the various situations of errors of forgetfulness.
Forgetting plans is actually uniform in meaning; its interpretation is, as we have heard, not denied even by the layman. The tendency interfering with the plan is always an