No. 503] NOTfiS AND LITERATURE 



755 



science. One need not hold that psychic factors are required for 

 explanation of the objective facts in order to sec the great in- 

 terest of this inquiry. 



The author therefore examines systematically the behavior of 

 animals, as discovered by experiment, from Amoeba to the apes, 

 attempting to show what psychic processes are. or may be, im- 

 plied. She readily admits the possibility that no psychic proc- 

 esses are present at all; but the question is this: If we assume 

 that psychic processes an present, and thai they follow rules 

 like those which they follow in man, then what ones appear to 

 be present in the different groups of animals.' In answering 

 this question, the principle of parsimony is taken as a guide: 

 "in no case may we interpret an action as the exercise of a 

 higher psychical faculty, if it can be interpreted as the outcome 

 of the exercise of one which stands lower in the psychological 

 scale." The undeniable dangers of this, in the evident fact that 

 nature doesn't always operate by what seems to our limited 

 view the simplest means, is expressly recognized, but the prin- 

 ciple is thought valuable for holding in check the common 

 tendency to attribute higher intellectual faculties to animals— 

 a tendency, we may remark, which in very recent times shows 

 some inclination to change into its opposite. 



After judicious introductory chapters on Difficulties .tin] Meth- 

 ods; on the Evidences of Mind, and on Mind in the Simplest 

 Animals, the main divisions of the hook are devoted to Sensory 

 Discrimination: Spatially Determined Reactions: Modification 

 by Experience: the .Memory Idea, and Attention. The devotee 

 of popular animal psychology will he surprised to find that the 

 word reason does not even occur in the index. The facts of 

 behavior are set forth clearly and accurately: the student even 

 of the strictly objective aspects of the subject will find this per- 

 haps the best compendium of the important fads that exists. 

 The treatment is throughout sane and conservative; it is analytic, 

 systematic and scientific — not in any sense popular, though clear. 

 Slips as to fads and details appear to be rare. All together 

 the treatment appears to one not a psychologist— to one who 

 "wants to be shown" — most satisfactory. Such a discussion 

 of these matters by a competent psychologist has been much 

 needed. 



The book gives the experimentalist an opportunity to compare 

 as to solidity and general sat isfadoriness. his own objective 



