Psychology of Animals. 211 



had observed the courtship of animals, and had con- 

 cluded that the female often chose a mate from out of a 

 number of rival suitors. Thus Bechstein concluded 

 that the hen-bird often selected the best singer as her 

 mate, (b) Darwin generalized the facts in his theory 

 of sexual selection, according to which many secondary 

 sex characters have been evolved through preferential 

 mating, the females choosing one male rather than 

 another, and that not whimsically, but in relation to 

 definite qualities, without which the male tended to 

 remain unmated. "If it be admitted", he said, "that 

 the females prefer, or are unconsciously excited by, the 

 more beautiful males, then the males would slowly but 

 surely be rendered more and more attractive through 

 sexual selection." As Lloyd Morgan tersely puts it, 

 " the hypothesis of sexual selection, stripped of all its 

 unnecessary aesthetic surplusage, suggests that the 

 accepted mate is the one that most strongly evokes the 

 pairing instinct", (c) Then followed what may be 

 called the biological criticism of the theory of selection. 

 Thus Wallace and others pointed out that there was 

 insufficient evidence to show (a) that the females did 

 really choose, or (b) that even the most unattractive 

 males remained unmated, the two most important 

 postulates of the theory. 



(ct) Within recent years a more exact psychological 

 study of mating has got under way, though it has not 

 advanced far beyond the stage of asking questions. 

 To what extent are the courtship activities instinctive? 

 How far is their definiteness sustained by tradition? 

 Is there any evidence of what might be called intention 

 in the dances and songs, the parades and displays of 

 the males, or is it all the expression of periodical fits 

 of exuberant gladness and uncontrolled emotional ec- 

 stasy? 



Here one needs to consider the modern theory of 

 emotions as due to visceral changes, evoked by exter- 

 nal or internal stimuli, which affect the brain through 

 afferent nerves, and are associated with motor impulses 

 which determine their external expression. If the 

 dance, the song, and the like are regarded as expres- 



