20 president's addbess. 



The luost important general advance seems to be the realisation that 

 the mind of the human adult is a social product ; that it can only be 

 understood in relation with the special environment in which it develops, 

 and with which it is in perpetual interaction. Professor Baldwin, of 

 Princeton, has done important work on this subject. Closely allied is 

 the study of what is called ' the psycliology of groups,' the laws of mental 

 action of the individual as modified by his membership of some form of 

 society. French authors have done valuable work here. 



These two developments of psychology are destined to provide the 

 indispensable psychological basis for Social Science, and for the anthro- 

 pological investigation of mental phenomena. 



Hereafter, the well-ascertained laws of experimental psychology will 

 undoubtedly furnish the necessary scientific basis of the art of education, 

 and psychology will hold the same relation to that art as physiology does 

 to the art of medicine and hygiene. 



There can be little doubt, moreover, of the valuable interaction of the 

 study of physical psychology and the theories of the origin of structural 

 character by natural selection. The relation of the human mind to tlie 

 mind of aniuials, and the gradual development of both, is a subject full of 

 rich stores of new material, yielding conclusions of the highest importance, 

 which has not yet been satisfactorily approached. 



I am glad to be able to give wider publicity here to some conclusions 

 which I communicated to the Jubilee volume of the ' Societe de Biolosie ' 

 of Paris in 1899. I there discussed the significance of the great inci-ease 

 in the size of the cerebral hemispheres in recent, as compared witli Eocene 

 Mammals, and in Man as compared Avith Apes, and came to the conclu- 

 sion that ' the power of building up appropriate cerebral mechanism in 

 response to individual experience,' or what may be called ' educability,' is 

 the quality which characterises the larger cerebrum, and is that which 

 has led to its selection, survival, and further increase in volume. The 

 bearing of this conception upon questions of fundamental importance in 

 what has been called genetic psychology is sketched as follows. 



'The character which we describe as "educability" can be trans- 

 mitted ; it is a congenital character. But the reseats of education can 

 not be transmitted. In each generation they have to be acquired afresh. 

 With increased " educability " they ai'e moje readily acquired and a larger 

 variety of them. On the other hand, the nerve-mechanisms of instinct 

 are transmitted, and owe their inferiority as compared with the results 

 of education to the very fact that they are not acquired by the individual 

 in relation to his particular needs, but have arisen by selection of con- 

 genital variation in a long series of preceding generations.' 



'To a large extent the two series of brain-mechanisms, the " instinc- 

 tive "and the " individually acquired," are in opposition to one another. 

 Congenital brain-mechanisms may prevent the education of the brain 

 and the development of new mechanisms specially fitted to the special 

 conditions of life. To the educable animal the ]e.ss tjiere is of specialised 



