The first question that arises in this inquiry is whether the smile or the laugh was the earlier to appear in the course of racial development. The expressions of animals below man do not offer any decisive clue here. The anthropoid apes appear both to produce a kind of smile or grin, and to utter sounds analogous to our laughter. It may, however, be contended that this so-called laughter is much less like our laughter than the grin is like our smile. In the absence of better evidence, the fact that the smile appears first in the life of the child must, according to a well-known law of evolution, be taken as favouring the hypothesis that man’s remote ancestors learned to smile before they could rise to the achievement of the laugh. This is further supported by the fact that, in the case of the individual, the laugh when it occurs announces a higher form of pleasurable consciousness, the level of perception {171} as distinguished from the level of sensation which is expressed by the first smile. Lastly, I am informed that among imbeciles the smile persists lower down in the scale of degeneration than the laugh. Dr. F. E. Beddard writes to me: “I remember once seeing a defective human monster (with no frontal lobes) whose only sign of intelligence was drawing up the lips when music was played”.[107] It is commonly held that, since the expression of pain, suffering, or apprehension of danger among animals is a much more pressing necessity for purposes of family and tribal preservation than that of pleasure or contentment, the former is developed considerably earlier than the latter. According to this view, we can understand why the adumbrations of a smile and a laugh which we find in animals closely related to man have been so imperfectly developed and appear only sporadically. Supposing that the smile was the first of the two expressive movements to appear in the evolution of the human species, can we conjecture how it came to be the common and best-defined expression of pleasurable states? In dealing with this point we may derive more definite aid from Darwin’s principles.