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The Psychology of Suggestion (1898)

New York: D. Appleton, pp. 5–18, 29–34, 297–311 [with elisions].

Published onFeb 25, 2024
The Psychology of Suggestion (1898)


Editor’s Introduction

Patrick Parsons

Where scholars like Le Bon and Baldwin employed suggestion and imitation in their larger analyses, Boris Sidis (1867–1923) focused on suggestion exclusively, writing the first book-length treatment of the subject. Sidis was born in the Ukraine and emigrated to the US in 1887 to escape Czarist political persecution. He earned an AB (1894), PhD (1897), and MD (1908) from Harvard University, where he studied under William James and specialized in abnormal psychology. He founded the Journal of Abnormal Psychology but spent most of his professional career as a practicing psychopathologist, also founding the New York State Psychopathic Institute.

As with Le Bon, his research interests were colored by his early experience with real-world mob behavior, in his case the witnessing of and escape from the violent Czarist pogroms of the 1880s. But while suggestion theory was the subject of Sidis’s analyses, he did not, interestingly, cite the work of Le Bon or Tarde. Instead, he built on then-popular research in hypnotic suggestion, especially Charcot, with whom he briefly studied, and added a few citations to Baldwin.

In February 1895, he published a popularized version of his views in the Atlantic Monthly, titled “A Study of the Mob.” With heavy reliance on research in hypnotism, the article attempted to explain mob behavior as a form of social hypnotism, with special attention to examples from, and conditions in, Czarist Russia.

Four years later, he released his scholarly examination of the subject, The Psychology of Suggestion, with an introduction by James. Notable again as the first book dedicated to suggestion theory, Sidis begins with an explanation of the basic concept as a process in which “the subject accepts uncritically the idea suggested to him, and carries it out almost automatically” (italics in the original). “Social suggestion” was the mechanism, either direct or indirect, which mobilizes the mob or the crowd. “Social life,” he declared, “presupposes suggestion…. Man is a social animal, no doubt: but he is social because he is suggestible.”

In the following excerpt, Sidis further distinguishes between normal and abnormal states of hypnosis and between individual “suggestibility” (one-on-one hypnosis) and “social suggestibility,” both with implications for theories of attitude change. Foreshadowing future studies in persuasion, he also offers observations on the impact, in practice, of the frequency of a suggestion and on what would later be called order effects: “Of all the modes of suggestion, however, the most powerful, the most effective, and the most successful is a skillful combination of frequency and last impression”(italics in the original). Relevant as well in today’s world of social media, he wrote in some detail about the nature of suggestion-driven social manias and public panics.

Like many of the Progressives who came after him, Sidis nonetheless retained optimism in the fundamental nature of people’s critical ability, especially when properly schooled. “In the spirit of his adoptive country, Sidis believed in the power of education in preparing the masses for more informed, rational decision making” (Prislin and Crano 2012, 322).

The Psychology of Suggestion (1898)

Boris Sidis

New York: D. Appleton, pp. 5–18, 29–34, 297–311 [with elisions].



PSYCHOLOGICAL investigators employ the term “suggestion” in such a careless and loose fashion that the reader is often puzzled as to its actual meaning. Suggestion is sometimes used for an idea bringing in its train another idea, and is thus identified with association. Some extend the province of suggestion and make it so broad as to coincide with any influence man exerts on his fellow-beings. Others narrow down suggestion and suggestibility to mere symptoms of hysterical neurosis. This is done by the adherents of the Salpêtrière school. Suggestion, again, is used by the Nancy school to indicate the cause which produces that peculiar state of mind in which the phenomena of suggestibility become especially prominent.

This vague and hazy condition of the subject of suggestion causes much confusion in psychological discussions. To free the subject from this confusion of tongues, we must endeavour in some way or other to give a strict definition of suggestion, and rigorously study the phenomena contained within the limited field of our investigation. We must not follow in the way of those writers who employ the terms suggestion and suggestibility in all possible meanings. Such carelessness can not but lead into a tangle of words. In order to give a full description of suggestion and make its boundary lines clear, distinct, and definite, let us take a few concrete cases and inspect them closely. […]

A stump orator mounts a log or a car and begins to harangue the crowd. In the grossest way he praises the great intelligence, the brave spirit of the people, the virtue of the citizens, glibly telling his audience that with such genius as they possess they must clearly see that the prosperity of the country depends on the politics he favours, on the party whose valiant champion he now is. His argumentation is absurd, his motive is contemptible, and still, as a rule, he carries the body of the crowd, unless another stump orator interferes and turns stream of sentiment in another direction. The speech of Antony in Julius Cæsar is an excellent example of suggestion.

All examples undoubtedly belong to the province suggestion. Now what are their characteristic traits? What are the elements common to all these cases of suggestion? We find in all these instances a stream of consciousness that goes on flowing in its peculiar, individual, idiosyncratic way; suddenly from the depths of the stream a wave rises to the surface, swamps the rest of the waves, overflows the banks, deflects for a while the course of the current, and then suddenly subsides, disappears, and the stream resumes its natural course, flowing once more in its former bed. On tracing the cause of this disturbance, we invariably find it is due to some external source, to some other stream running alongside the one disturbed. Stating the same in the language of Baldwin, we may say that “by suggestion is meant a great class of phenomena typified by the abrupt entrance from without into consciousness—of an idea or image which becomes a part of the stream of thought, and tends to produce the muscular and volitional efforts which ordinarily follow upon its presence.”1

Is this our last say of suggestion? Far from being the case. On closer inspection of our examples we find traits which are of the utmost importance. The subject accepts uncritically the idea suggested to him, and carries it out almost automatically. […]

By suggestion is meant the intrusion into the mind of an idea; met with more or less opposition by the person; accepted uncritically at last; and realized unreflectively, almost automatically.

By suggestibility is meant that peculiar state of mind which is favourable to suggestion.


ONCE the subject-matter under investigation is defined, we must proceed to a further subdivision of it; we must define and classify the different species of suggestion and suggestibility. Already in our last chapter, in adducing different cases of suggestion, suggestibility in the normal state was tacitly implied. We have reached a stage in our discussion in which we must state this fact more explicitly. The soil favourable for seeds of suggestion exists also in what we call the individual. Suggestibility is present in what we call the normal state, and in order to reveal it we only know how to tap it. The suggestible element is a constituent of our nature; it never leaves us; it is always present in us. Before Janet, Binet, and other investigators undertook the study of hysterical subjects, no one suspected the existence of those remarkable phenomena of double consciousness that opened for us new regions in the psychical life of man. Phenomena were merely not noticed, although all the while; and when at times they rose from their obscurity, came to light, and obtruded themselves on the attention of people, they were either put down as sorcery, witchcraft, or classed contemptuously with lying, cheating and deception. The same is true with regard to normal suggestibility. It rarely attracts our attention, as it manifests itself in but trifling things. When, however, it rises to the surface and with the savage fury of a hurricane cripples and maims on its way everything it can not destroy, menaces life, and throws social order into the wildest confusion possible, we put it down as mobs. We do not in the least suspect that the awful, destructive, automatic spirit of the mob moves in the bosom of the peaceful crowd, reposes in the heart of the quiet assembly, and slumbers in the breast of the law-abiding citizen. We do not suspect that the spirit of suggestibility lies hidden even in the best of men; like the evil jinnee of the Arabian tales is corked up in the innocent-looking bottle. Deep down in the nature of man we find hidden the spirit of suggestibility. Every one of us is more or less suggestible. Man is often defined as a social animal. This definition is no doubt true, but it conveys little information as to the psychical state of each individual within society. There exists another definition which claims to give an insight into the nature of man, and that is the well-known ancient view that man is a rational animal; but this definition breaks down as soon as we come to test it by facts of life, for it scarcely holds true of the vast multitudes of mankind. Not sociality, not rationality, but suggestibility is what characterizes the average specimen of humanity, for man is a suggestible animal.

The fact of suggestibility existing in the normal individual is of the highest importance in the theoretical field of knowledge, in psychology, sociology, ethics, history, as well as in practical life, in education, politics, and economics; and since this fact of suggestibility may be subject to doubt on account of its seeming paradoxicalness, it must therefore be established on a firm basis by a rigorous experimentation, and I have taken great pains to prove this fact satisfactorily. The evidence for the existence of normal suggestibility I shall adduce later on in our discussion; meanwhile I ask the reader to take it on trust, sincerely hoping that he will at the end be perfectly satisfied with the demonstration of its truth.

The presence of suggestibility in such states as the hysterical and the hypnotic is a fact well proved and attested, and I think there is no need to say a word in its defence. Since the hysterical, the hypnotic, the somnambulic states do not belong to the routine of our experience; since they are but rare and occur under special peculiar conditions; since they unfit one for social life, disable in the struggle for existence, I think the reader will not quarrel with me for naming such states abnormal.

Thus it becomes quite clear that suggestibility must be classed under two heads: (1) Suggestibility in the normal state, or normal suggestibility, and (2) suggestibility in the abnormal state, or abnormal suggestibility. [...]

While looking for evidence for normal suggestibility, an opportunity was also taken to arrange the experiments according to different factors, so that should it be proved that suggestion in the normal state is an indubitable fact, we should be enabled to know what kind of factors are the more impressive and suggestive.

The series of letters and figures were arranged according to the following factors and their combinations: 1. Repetition. 2. Frequency 3. Coexistence. 4. Last impression. [...]

On the whole, we may say that in the normal state temporal or spatial repetition is the most unfortunate mode of suggestion, while the best, the most successful of all the particular factors, is that of the last impression—that is, the mode of bringing the idea intended for suggestion at the very end. This rule is observed by influential orators and widely read popular writers; it is known in rhetoric as bringing the composition to a climax. Of all the modes of suggestion, however, the most powerful, the most effective, and the most successful is a skillful combination of frequency and last impression. This rule is observed by Shakespeare in the speech of Antony. Be these rules of the particular factors what they may, one thing is clear and sure: these experiments unquestionably prove the reality of normal suggestibility; they prove the presence of suggestibility in the average normal individual. […]



SUGGESTIBILITY is a fundamental attribute of man’s nature. We must therefore expect that man, in his social capacity, will display this general property; and so do we actually find the case to be. What is required is only the condition to bring about a disaggregation in the social consciousness. This disaggregation may either be fleeting, unstable—then the type of suggestibility is that of the normal one; or it may become stable—then the suggestibility is of the abnormal type. The one is the suggestibility of the crowd, the other that of the mob. In the mob direct suggestion is effective, in the crowd indirect suggestion. The clever stump orator, the politician, the preacher, fix the attention of their listeners on themselves, interesting them in the subject. They as a rule distract the attention of the crowd by their stories, frequently giving the suggestion in some indirect and striking way, winding up the long yarn by a climax requiring the immediate execution of the suggested act. Out of the infinite number of cases, I take the first that comes to my hand:

In August 11, 1895, at Old Orchard, Me., a camp meeting was held. The purpose was to raise a collection for the evangelization of the world. The preacher gave his suggestions in the following way: “The most impressive memory I have of foreign lands is the crowds, the billows of lost humanity dashing ceaselessly on the shores of eternity.... How desperate and unloved they are—no joy, no spring, no song in their religion! I once heard a Chinaman tell why he was a Christian. It seemed to him that he was down in a deep pit, with no means to get out. [Story.] Have you wept on a lost world as Jesus wept? If not, woe unto you. Your religion is but a dream and a fancy. We find Christ testing his disciples. Shall he make them his partners ? Beloved, he is testing you to-day. [Indirect suggestion.] He could convert one thousand millionaires, but he is giving us a chance. [Suggestion more direct than before.] Have we faith enough? [A discourse on faith follows here.] God can not bring about great things without faith. I believe the coming of Jesus will be brought about by one who believes strongly in it.... Beloved, if you are going to give grandly for God you have got faith. [The suggestion is still more direct.] The lad with the five loaves and the two small fishes [story]—when it was over the little fellow did not lose his buns; there were twelve baskets over.... Oh, beloved, how it will come back!... Some day the King of kings will call you and give you a kingdom of glory, and just for trusting him a little! What you give to-day is a great investment.... Some day God will let us know how much better he can invest our treasures than we ourselves.” The suggestion was effective. Money poured in from all sides, contributions ran from hundreds into thousands, into tens of thousands. The crowd contributed as much as seventy thousand dollars.

A disaggregation of consciousness is easily effected in the crowd. Some of the conditions of suggestibility work in the crowd with great power and on a large scale. The social psychical scalpels are big, powerful; their edges are extremely keen, and they cut sure and deep. If anything gives us a strong sense of our individuality, it is surely our voluntary movements. We may say that the individual self grows and expands with the increase of variety and intensity of its voluntary activity; and conversely, the life of the individual self sinks, shrinks with the decrease of variety and intensity of voluntary movements. We find, accordingly, that the condition of limitation of voluntary movements is of great importance in suggestibility in general, and this condition is of the more importance since it, in fact, can bring about a narrowing down of the field of consciousness with the conditions consequent on that contraction—all favourable to suggestibility. [...]

Besides limitation of voluntary movements and contraction of the field of consciousness, there are also present in the crowd, the matrix of the mob, the conditions of monotony and inhibition. When the preacher, the politician, the stump orator, the ringleader, the hero, gains the ear of the crowd, an ominous silence sets in, a silence frequently characterized as “awful.” The crowd is in a state of overstrained expectation; with suspended breath it watches the hero or the interesting, all-absorbing object. Disturbing impressions are excluded, put down, driven away by main force. So great is the silence induced in the fascinated crowd, that very frequently the buzzing of a fly, or even the drop of a pin, can be distinctly heard. All interfering impressions and ideas are inhibited. The crowd is entranced, and rapidly merges into the mob-state. [...]

The given suggestion reverberates from individual to individual, gathers strength, and becomes so overwhelming as to drive the crowd into a fury of activity, into a frenzy of excitement. As the suggestions are taken by the mob and executed the wave of excitement rises higher and higher. Each fulfilled suggestion increases the emotion of the mob in volume and intensity. Each new attack is followed by a more violent paroxysm of furious demoniac frenzy. The mob is like an avalanche: the more it rolls the more menacing and dangerous it grows. The suggestion given by the hero, by the ringleader, by the master of the moment, is taken up by the crowd and is reflected and reverberated from man to man, until every soul is dizzied and every person is stunned. In the entranced crowd, in the mob; every one influences and is influenced in his turn; every one suggests and is suggested to, and the surging billow of suggestion swells and rises until it reaches a formidable height. [...]

The consciousness of the mob is reflex in its nature. In the entranced crowd, in the mob, social consciousness is disaggregated, thus exposing to the direct influence of the environment the reflex consciousness of the social subwaking self. The subwaking mob self slumbers within the bosom of society.


When animals, on account of the great dangers that threaten them, begin to rove about in groups, in companies, in herds, and thus become social, such animals, on pain of extinction, must vary in the direction of suggestibility; they must become more and more susceptible to the emotional expression of their comrades, and reproduce it instantaneously at the first impression. When danger is drawing near, and one of the herd detects it and gives vent to his muscular expression of fear, attempting to escape, those of his comrades who are most susceptible reproduce the movements, experience the same emotions that agitate their companion, and are thus alone able to survive in the struggle for existence. A delicate susceptibility to the movements of his fellows is a question of life and death to the individual in the herd. Suggestibility is of vital importance to the group, to society, for it is the only way of rapid communication social brutes can possibly possess. Natural selection seizes on this variation and develops it to its highest degree. Individuals having a more delicate susceptibility to suggestions survive, and leave a greater progeny which more or less inherit the characteristics of their parents. In the new generation, again, natural selection resumes its merciless work, making the useful trait of suggestibility still more prominent, and the sifting process goes on thus for generations, endlessly. A highly developed suggestibility, an extreme, keen susceptibility to the sensori-motor suggestions, coming from its companions, and immediately realizing those suggestions by passing through the motor processes it witnesses, is the only way by which the social brute can become conscious of the emotions that agitate its fellows. The sentinel posted by the wasps becomes agitated at the sight of danger, flies into the interior of the nest buzzing violently, the whole nestful of wasps raises a buzzing, and is thus put into the same state of emotion which the sentinel experiences.

Suggestibility is the cement of the herd, the very soul of the primitive social group. A herd of sheep stands packed close together, looking abstractedly, stupidly, into vacant space. Frighten one of them; if the animal begins to run, frantic with terror, a stampede ensues. Each sheep passes through the movements of its neighbour. The herd acts like one body animated by one soul. Social life presupposes suggestion. No society without suggestibility. Man is a social animal, no doubt; but he is social because he is suggestible. Suggestibility, however, requires disaggregation of consciousness; hence, society presupposes a cleavage of the mind, it presupposes a plane of cleavage between the differentiated individuality and the undifferentiated reflex consciousness, the indifferent subwaking self. Society and mental epidemics are intimately related; for the social gregarious self is the suggestible subconsciates self.

The very organization of society keeps up the disaggregation of consciousness. The rules, the customs, the laws of society are categorical, imperative, absolute. One must obey them on pain of death. Blind obedience is a social virtue. But blind obedience is the very essence of suggestibility, the constitution of the disaggregated subwaking self. Society by its nature, by its organization, tends to run riot in mobs, manias, crazes, and all kinds of mental epidemics.

With the development of society the economical, political, and religious institutions become more and more differentiated; their rules, laws, by-laws, and regulations become more and more detailed, and tend to cramp the individual, to limit, to constrain his voluntary movements, to contract his field of consciousness, to inhibit all extraneous ideas—in short, to create conditions requisite for a disaggregation of consciousness. If, now, something striking fixes the attention of the public—a brilliant campaign, a glittering holy image, or a bright “silver dollar”—the subwaking social self, the demon of the demos, emerges, and society is agitated with crazes, manias, panics, and mental plagues of all sorts. 

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