STANDARDIZED TESTS AND 



MENTAL INHERITANCE 



Very Young Children Already Show Great Variation in Special Aptitudes — 



These Differences Are Probably Not to Be Accounted for by 



Differences in Environment — More Tests Needed 



June E. Downey, Ph.D. 



Professor of Psychology, University of Wyoming, Laramie, Wyoming 



THE development by psychology of 

 standardized tests of mental ca- 

 pacity and the establishment of 

 norms of performance for differ- 

 ent ages has, among its other possibili- 

 ties, opened the way for exact studies 

 of mental inheritance. Goddard's utili- 

 zation of the Binet Scale of Intelligence 

 in establishing the heritableness of 

 feeble-mindedness as a Mendelian re- 

 cessive is but the first breaking of 

 ground. Other suggestions of profitable 

 investigation crowd upon the attention. 

 For instance, the possible identification, 

 by help of the scales, of carriers of 

 mental defects and pure normals. Prob- 

 ably these two types will show signifi- 

 cant differences in their reactions to 

 standardized mental tests and they can 

 in this way be differentiated from one 

 another for eugenic purposes — a most 

 desirable thing. 



Again, the study of the supernormal 

 child is incomplete unless we have some 

 means of determining the kinds of mat- 

 ing that produce such progeny. With 

 the accumulation of data incident to the 

 very extensive intelligence testing which 

 is now being carried on, material will 

 be at hand for the formulation of the 

 laws governing the transmission of de- 

 grees of general intelligence. Certainly 

 it is significant that of groups of parents 

 and children recently tested by my 

 pupils the combination of parents, both 

 of whom made a record of superior 

 mentality by the Stanford adult scale, 

 gave 80% of children making a superior 

 or very superior record ; while when 

 only one parent gave a superior record 



or both made only an average one, the 

 percentage of superior children was 

 only ZZ. Our groups were too small to 

 permit our drawing any dogmatic con- 

 clusions, but they certainly encourage 

 further investigation. 



Another utilization of standardized 

 tests consists in such early determina- 

 tion of special capacity as eliminates 

 the possibility of the gift in question, 

 being the outcome of a peculiarly fa- 

 vorable environment. Every investi- 

 gator of mental inheritance encounters 

 a difficulty in distinguishing between 

 environmental and congenital factors. 

 The proof that a capacity above the 

 average was manifest at too early an 

 age to permit accounting for it on the 

 ground of training, stamps that capacity 

 as congenital and, probably, as germi- 

 nal. In spectacular cases of genius, 

 musical and mathematical prodigies, for 

 instance, the general public has not been 

 blind to the bearing of the facts upon 

 the theory of original capacity, but when 

 talent of low degree or specialized abil- 

 ity of any sort is in question the in- 

 ference of its inheritance has seemed 

 less inevitable. Only the employment 

 of norms, which give us the range of 

 performance for various ages, can en- 

 able us to identify with confidence a 

 native capacity at a very early age. My 

 records on children show a nmnber of 

 very interesting instances of the kind in 

 question. 



SENSING WEIGHTS 



Cases I and II. The children con- 

 •cerned, Bertha C. (age nine years two 

 months), and Clifford C. (age six years 



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