Sexual Selection 439 
The view here put forward, which has been developed by Prof. Groos?, 
therefore seems to have Darwin’s own sanction. The phenomena are 
not only biological ; there are psychological elements as well. One 
can hardly suppose that the female is unconscious of the male’s 
presence ; the final yielding must surely be accompanied by height- 
ened emotional tone. Whether we call it choice or not is merely a 
matter of definition of terms. The behaviour is in part determined 
by supplementary psychological values. Prof. Groos regards the coy- 
ness of females as “a most efficient means of preventing the too early 
and too frequent yielding to the sexual impulse*.” Be that as it may, 
it is, in any case, if we grant the facts, a means through which male 
sexual behaviour with all its biological and psychological implica- 
tions, is raised to a level otherwise perhaps unattainable by natural 
means, while in the female it affords opportunities for the develop- 
ment in the individual and evolution in the race of what we may 
follow Darwin in calling appreciation, if we empty this word of the 
aesthetic implications which have gathered round it in the mental 
life of man. 
Regarded from this standpoint sexual selection, broadly con- 
sidered, has probably been of great importance. The psychological 
accompaniments of the pairing situation have profoundly influenced 
the course of biological evolution and are themselves the outcome of 
that evolution. 
Darwin makes only passing reference to those modes of behaviour 
in animals which go by the name of play. “Nothing,” he says’, “is 
more common than for animals to take pleasure in practising what- 
ever instinct they follow at other times for some real good.” This is 
one of the very numerous cases in which a hint of the master has 
served to stimulate research in his disciples. It was left to Prof. Groos 
to develop this subject on evolutionary lines and to elaborate in a 
masterly manner Darwin’s suggestion. “The utility of play,” he says‘, 
“ig incalculable. This utility consists in the practice and exercise it 
affords for some of the more important duties of life,”—that is to say, 
for the performance of activities which will in adult life be essential 
to survival. He urges® that “the play of young animals has its origin 
in the fact that certain very important instincts appear at a time 
when the animal does not seriously need them.” It is, however, 
questionable whether any instincts appear at a time when they are 
not needed. And it is questionable whether the instinctive and 
emotional attitude of the play-fight, to take one example, can be 
identified with those which accompany fighting in earnest, though 
1 The Play of Animals, p, 244, London, 1898. 2 bid. p. 283. 
3 Descent of Man, Vol. 1. p. 60; (Popular edit.), p. 566. 
4 The Play of Animals, p. 76. 5 Ibid. p. 75, 
