LAUGHTER is commonly regarded as the expression of various feelings, such as sheer joy, lightness of heart, amusement, and feelings more grave than any of these. It is mainly a human phenomenon. Among lower animals laughter is a very rare occur rence if, indeed, it is met with at all. Man is the laughing animal par excellence. And man is also the principal butt of laughter, though not the only one. He is the most laughed at as well as the chief or sole laughing animal. From the point of view of the student of psychology laughter presents the following main prob lems: (I) What is it that provokes laughter? Intimately con nected with this problem is the question whether or no there are different varieties of laughter. (2) The second main problem is: What is the function of laughter? (i.) The Causes of Laughter.—One obvious cause of laughter barely deserves passing mention, namely, tickling. This sort of laughter is a purely physiological or reflex reaction, and not the spontaneous expression of a feeling. And here we are only con cerned with laughter as an expression of feeling induced by the observation, memory, imagination, or contemplation of some thing or other. The problem before us is, what kind of things or situations make us laugh, or are felt to be ludicrous, when we observe or contemplate them? Some writers have attempted to reduce them all to one class, or to find in them all one com mon characteristic which makes them ludicrous or provokes us to laughter. But these writers do not agree among them selves; each identifies the common cause or essential character istic with some other feature of the ludicrous situation. Thus Hobbes, for instance, held that any awkwardness or other deform ity or imperfection in others makes one laugh because it heightens his self-esteem and so pleases him. The same sort of "sudden glory" (as Hobbes calls it) may be produced more directly by the apprehension of some excellence in oneself. Such exultation may account for some cases of laughter, but certainly not for all cases. Schopenhauer, on the other hand, found the cause of laughter in the incongruity of what is apprehended. The sudden perception of incongruity certainly is a frequent source of laughter, and a common device for provoking it. Recently Bergson has attempted another general explanation. According to him, it is always the perception of the substitution of mere mechanism for adaptive pliancy that provokes laughter. Many cases of laughter caused by observed awkwardness, carelessness, thoughtless routine, etc., would certainly come under Bergson's description. But as an all inclusive theory Bergson's view cannot be regarded as satisfac tory. Prima faci-, it seems unlikely that any uniform explanation will fit all the facts. Everyday language seems to bear witness to the existence of different kinds of laughter, provoked by different kinds of causes or situations. We commonly distinguish somehow between the ridiculous, the comic, the humorous, etc., on the one hand, and between laughter that is gay or grave, derisive or scornful, etc., on the other hand. In Heine's poem called "Woman," the four stanzas of which it is made up depict each a totally different situation, passing from gaiety to tragedy, but each ends "and she laughed." Needless to say, the laughter is very different in each case, as every good recitation of the poem makes the hearer realize.
(2.) The Function of Laughter.—For the merely physiologi cal function of laughter a passing reference must suffice—laughter benefits the lungs and is an outlet for some forms of superfluous energy. But we are concerned with the mental function or func
tions of laughter. In a general sort of way it is commonly realized that laughter has a useful function in human life. Laughter enables man to beguile the present, just as forgetfulness shields him from the past, and hope helps him to face the future. But, leaving aside such vague popular philosophy, various theories have been put forward by psychologists and philosophers. The most interesting of them is the view of Bergson. Bergson begins by pointing out that laughter is mainly a social phenomenon. "Our laughter" (he says) "is always the laughter of a group. It may, perchance, have happened to you, when sitting in a railway car riage or at a table d'hôte, that you heard travellers relating to one another stories which must have appeared comic to them, for they laughed heartily. If you had been one of their company, you would have laughed with them but, as you were not, you ' felt no desire whatever to do so. A man who was once asked why he did not weep at a certain sermon, when everybody else was shedding tears, replied : 'I don't belong to this parish.' What that man felt about tears is even more true of laughter. However spontaneous it seems, laughter always implies a kind of free masonry, or even complicity, with other laughers, real or imagi nary. It has often been remarked that the fuller the house, the more uncontrolled is the laughter of the audience. On the other hand, as has also often been remarked, many comic effects cannot be translated from one language into another, because they refer to the habits and thoughts of a particular social group." It seems, therefore, natural that Bergson should attribute to laughter a special social function. And so he does. Laughter, according to Bergson, is a kind of social "ragging," a method of "breaking in" people to the forms and conventions of society, a way of curing eccentricity and unsociability in their early stages. "What life and society require of each of us is a constantly alert attention, that discerns the outlines of the present situation, together with a certain elasticity of mind and body to enable us to adapt our selves accordingly. Tension and elasticity are two mutually com plementary forces which life brings into play. If these two forces are lacking in the body to any considerable extent, we have sickness and infirmity and accidents of every kind. If they are lacking in the mind, we find every degree of mental deficiency, every variety of insanity. Finally, if they are lacking in the character, we have cases of the gravest inadaptability to social life. . . . Society is therefore suspicious of all inelasticity of char acter, of mind, and even of body, because it is the possible sign of a slumbering activity as well as of an activity with separatist tendencies that inclines to swerve from the common centre round which society gravitates. . . . And yet society cannot intervene at this stage by material repression, since it is not affected in a material fashion. It is confronted with something that makes it uneasy, but only as a symptom—scarcely a threat at the very most a gesture. A gesture, therefore, will be its reply. Laughter must be something of this kind, a sort of social gesture."