82 THE POPULAR SCIENCE MONTHLY 



THE PSYCHOLOGY OF MENTAL DEFICIENCY 



By BIRD T. BALDWIN, Ph.D. 



UNIVERSITY OF TEXAS 



Come wander with me . . . 

 Into regions yet untrod, 

 And read what is still unread 

 In the manuscript of God. 



THIS thought, which a few generations ago was uppermost in the 

 mind of the great Agassiz when making his geological explora- 

 tions, is to-day finding one form of expression in the scientific labora- 

 tory for psychological research at Vineland, N. J., where investigations 

 are being made on the causes and conditions of human degeneration 

 and mental deficiency. More vigorously to-day than ever before in the 

 history of civilization, social, educational and psychological investiga- 

 tions are being carried into all phases of life with its misery, happiness 

 and usefulness. Associations for charities, children's aid societies, 

 guilds, juvenile courts and public school authorities, are asking the 

 psychologists and physicians what can be done with these unfortunate 

 people, the mental defectives, who are contaminating society by their 

 presence, absorbing the time and thought that should be devoted to 

 :normal children, and later filling the almshouses, charitable institu- 

 tions and prisons with illegitimate and irresponsible offspring. 



The psychologist who analyzes, classifies, describes and explains men- 

 tal phenomena is beginning to work effectively on the insane, the crimi- 

 nal and the defective. From a psychological standpoint, the border line 

 between dull, backward and retarded children and those mentally de- 

 fective, lies in a difficult and unexplained region. The inadequate 

 knowledge of mental capacities and the desirability of accurately ex- 

 pressing the relative educational values of such capacities makes the 

 field a most fertile one for research. With others, Ayres and Gulick 

 have been studying the " laggards of our schools " for the Eussell Sage 

 Foundation, and Witmer, a pioneer in the field, has established the 

 Psychological Clinic for the study of the normal development of every 

 child. What of truly subnormal and mentally deficient children ? 



The study of mentally defective children began in 1797 when some 

 French soldiers found " the wild boy of Aveyron " in a forest and had 

 him taken to Dr. Pinel, of Paris, for examination. Pinel pronounced 

 him incurable, which caused the publication of a pamphlet three years 

 later by Itard, " De L'education d'un Homme Sauvage." This was the 

 first important contribution to the literature of the subject; the second 



