Animal Psychology, the Old and the New 27 



Mental Evolution in Man are among the best-known 

 products of this movement. 



There was a strong tendency toward anthropo- 

 morphism in many post-Darwinian writers, as there 

 was in several of the skeptics of the eighteenth cen- 

 tury. The effort to show that the human mind 

 evolved from the animal mind led many to read an 

 undue amount of intelligence into the activities of 

 animals. The works of Perty, Biichner, Vogt, 

 Brehm, and to a certain extent Romanes afford illus- 

 trations of this failing. What Wasmann calls "hu- 

 manizing the brute" became a favorite theme. Sev- 

 eral writers of the early post-Darwinian period 

 restrained within reasonable limits whatever bias 

 they may have had toward anthropomorphism, and 

 contributed observations and experiments which have 

 thrown much light on the problems of animal psy- 

 chology. Among these may be mentioned Lubbock, 

 Forel, Lloyd Morgan, Dr. and Mrs. Peckham, Mc- 

 Cook and many others. The scholarly works of 

 Groos on The Play of Animals and The Play of Man 

 are excellent examples of the application of Darwin- 

 ian principles to the interpretation of behavior. 



Among post-Darwinian authors on animal psy- 

 chology there soon arose a division between the neo- 

 Darwinians who attributed evolution mainly or 

 solely to natural selection, and the neo-Lamarckians 

 who attached much greater importance to the in- 

 heritance of the effects of experience. This division 



