We may perhaps sum up the special conditions of the laughter-process under tickling as follows: when a child is tickled he is thrown into an attitude of indefinite expectancy. He is expecting contact, but cannot be sure of the exact moment or of the locality. This element of uncertainty would in itself develop the attitude into one of uneasiness and apprehensiveness; and this happens save when the child is happy and disposed to take things lightly and as play. In this case we may suppose that the half-developed mild form of fear is each time swiftly dissolved into nothing by a recognition of the unreality of the cause, of the fact that the touches are harmless and come from the good-natured mother or nurse by way of play. This recognition becomes clearer as the process is continued, and so there supervenes a new attitude, that of play, in which all {64} serious interpretation is abandoned and the gentle attacks are accepted as fun or make-believe.
If this is a correct analysis of the experience of the tickling which excites laughter, we seem to have in it at a very early age elements which are to be found, in a more fully developed form, in the later and more complex sorts of mirth, namely, relief from a serious and constrained attitude, a transition from a momentary apprehension induced by the presentation of the partially unknown, to a joyous sense of harmless make-believe. That this is so is further evidenced by the familiar fact that a child, when used to the game, will begin to laugh vigorously when you only threaten with the advancing fingers. As a German writer observes, this is a clear case of Lipps’ theory of annihilated expectation;[43] only he omits to note that the laughter depends, not on the mere fact of annihilation, but on the peculiar conditions of it in this case, involving a slight shock at the approach of something partially unknown to a specially sensitive region of the organism, and the instant correction of the apprehension by a recognition of its harmlessness.
Much the same kind of stimulative process seems to be present in the other and allied cases of reflex or quasi-reflex laughter. It is well known that certain sense-stimuli which excite sensations of a disagreeable character, but which, though acute, are not violent, such as the application of a cold douche, are apt to provoke laughter. According to the German authority just quoted, the effect depends here, too, on variation in respect of the intensity and the locality of the stimulation. He found further, in carrying out psychological experiments, that whereas the introduction of a stronger stimulus than was expected is apt to excite apprehension in {65} the subject, that of a weaker stimulus will excite laughter.[44] Here, too, we seem to have a sensational reflex in which is present a distinctly mental element, viz., a moment of mild shock and apprehension at the sudden coming of something disagreeable and partially unknown, instantly followed by another moment of dissolution of shock in a pleasurable recognition of the harmlessness of the assault.
2. Laughter is not, however, always of this reflex form. It may arise without sensory stimulation in an “automatic” manner as the result of a cerebral rather than of a peripheral process. This is illustrated by the seemingly causeless laughter which breaks out in certain abnormal states and has an “uncanny” aspect for the sane observer. A well-known example of this is the effect of the action on the brain centres of laughing gas and other substances. Such “automatisms” occur, however, within the limits of normal experience, as when a person laughs during a state of high emotional tension. I propose to speak of such seemingly uncaused reactions as nervous laughter.[45]
A common and simple variety of this nervous laughter is the spasmodic outburst that often succeeds a shock of fear. A child will laugh after being frightened by a dog; a woman often breaks out into a nervous laugh after a short but distinctly shaking experience of fear, e.g., in a carriage behind a runaway horse, or in a boat which has nearly capsized. And it does not seem that such laughter is preceded by a perception of the absurdity of the fear, or of any similar mode of consciousness; it looks like a kind of physiological reaction after the fear. {66}
The same thing will show itself in circumstances which give rise to a prolonged mental attitude, involving a feeling of apprehensiveness and of constraint. Thus a shy man, making his first essay as a public speaker, will sometimes betray his nervousness on the platform by weird little explosions of laughter as well as by awkward gestures. I have noted the same thing in strangers to whom I have spoken at a table d’hôte abroad. The way in which little spasms of laughter are apt to intrude themselves into situations which, by making us the object of others’ special attention, bring an awkward consciousness of insecurity, is further illustrated in the behaviour of many boys and girls when summoned to an interview with the Head, in the laughter which often follows the going up to take a prize before a large assembly, and the like. The strong tendency to laugh which many persons experience during a solemn ceremony, say a church service, may sometimes illustrate the same effect. When an enforced attitude, difficult to maintain for the required length of time, brings on the impulse, this will gather strength from the growth of a feeling of apprehension lest we should not be equal to the test imposed.
Another variety, coming under the head of nervous laughter, is the sudden outburst which now and again occurs in a state of great emotional strain, having a distinctly painful character, especially when it includes something in the nature of a shock. The news of the death of an acquaintance has been known to excite a paroxysm of laughter in a company of young persons from nineteen to twenty-four years of age.[46] One may assume here that the {67} outbreak is not the direct result of the news, but depends on the effect of the shock, with the abnormal cerebral tension which this involves.
A like spasmodic outburst of laughter occasionally occurs during a more prolonged state of painful emotional excitement. It sometimes intrudes itself into a bout of physical suffering. Lange speaks of a young man who, when treated for ulceration of the tongue by a very painful caustic, regularly broke out into violent laughter when the pain reached its maximum.[47] Many persons when thrown into a prolonged state of grief, accompanied by weeping, exhibit a tendency to break out into laughter towards the end of the fit. Shakespeare illustrates this tendency when he makes Titus Andronicus, whose hand has been cut off, answer the question why he laughed with the exclamation: “Why I have not another tear to shed”.[48]
Can we find a common element in these different forms of nervous or apparently unmotived laughter? We appear to have in all of them a preceding state of consciousness which is exceptionally intense and concentrated. The situation of fear, of constraint on being made the object of others’ unusual observation, of suddenly hearing news of deep import for which the mind is not prepared, of prolonged emotional agitation, these all involve an intensification of the psycho-physical processes which immediately condition our states of consciousness. Looking at these intensified {68} forms of consciousness more closely, we observe that they include something in the nature of psychical pressure, of the presence of forces which make for disorder, whereas the situation calls for severe self-control. This special strain thrown on the volitional process is illustrated in the demand for closer observation and calm reflection during a fit of fear, or other emotional excitement, which tends to bring about a state of wild movement and of disorderly ideas. It is, I believe, the specially severe strain belonging to such an attitude which is the essential pre-condition of the laughter. It makes the attitude a highly artificial one, and one which it is exceedingly difficult to maintain for a long period. As such, the attitude is eminently unstable, and tends, so to say, to break down of itself; and will certainly collapse, partially at least, if the demand seems, though only for a moment, to grow less imperative. Hence the readiness with which such a means of temporary relief as laughter undoubtedly supplies is seized at the moment.
It remains to determine the character of this sudden relaxation of the strain of attention more precisely. As a sudden collapse, it is clearly to be distinguished from the gradual breakdown due to “mental fatigue” and nervous exhaustion. The psycho-physical energy concentrated for the special purpose of meeting the strain is by no means used up, but has to find some way of escape. Here, no doubt, we seem to come across Mr. Spencer’s ingenious idea that laughter is an escape of nervous energy which has suddenly been set free. It is no less evident that the redundant energy follows the direction of the risible muscles because no other commanding object for the attention presents itself at the moment. The innervation of these muscles is not a mere diversion of attention: it is a dispersion of the energies which for the maintenance of attention ought to {69} be concentrated. We are never less attentive during our waking life than at the moment of laughter. Yet even here, I think, the theory of a convenient waste-pipe arrangement is not adequate. There is, I take it, in the case a relief of sur-charged nerve-centres, which process would seem to be better described by the figure of a safety-valve arrangement.