34 



SCIENCE 



[N. S. Vol. LIII. No. 1359 



tory of science, and still society would receive 

 eight tenths of our services as a free gift. 



The tests of individual differences devised 

 by a few psychologists in the course of the 

 past thirty years have been dramatically ex- 

 ploited by the tragedy of war. These meas- 

 lurements of general intelligence and special 

 aptitudes are interwoven with the whole fabric 

 of the mantle of science, but the direct work 

 of consequence involved in their development 

 was done by a score of us in the intervals be- 

 tween the hours of our employment. When a 

 committee was formed to adjust these tests 

 to the needs of the army not even our travel- 

 ing expenses were paid. An officer high in 

 the army has estimated at a billion dollars 

 the value of the gift gladly made to the na- 

 tion ; it would indeed have been so much if the 

 war had been long continued. At a cost of 

 about fifty cents each, tests were made on 

 nearly two million recruits, and the value 

 of each for purposes of promotion, elimina- 

 tion and selection appears to have been some- 

 where between ten and one himdred dollars. 

 The economic value of such tests for school 

 systems, for the government service, for in- 

 dustries, in all cases where individuals are 

 selected for work, for promotion or for special 

 tasks, is equally great. 



By psychological tests made in an hour and 

 at a nominal cost, we may tell better to what 

 classes children shovdd be assigned in school 

 than can the teachers who have taught them 

 for months. We may tell better from such 

 tests whether a boy is fit for college or for a 

 scholarship there than from a mnemonic ex- 

 amination in preparation for which years of 

 his life have in large part been misspent. We 

 may select recruits for promotion or for spe- 

 cial assignments in the army more accurately 

 than can their superior officers. We may 

 determine the fitness of clerks, telephone girls 

 and many other groups better than can their 

 employers. With increased knowledge such 

 as can be gained from further research, we 

 may be able to double the productivity of 

 labor by selecting individuals for the work for 

 which they are best fit, all the way from the 

 moron to the president of the nation. That 



would mean an annual increase in wealth of 

 seventy billion dollars a year for this country, 

 of five times as much for the world. 



The productivity of labor can probably 

 again be doubled by such improvements in 

 the environment as it is within our power to 

 make. This is largely the province of the 

 material sciences, but the reactions of the 

 human machine are of immense importance. 

 There are innumerable problems awaiting in- 

 vestigation and solution. Such are: the de- 

 sirable hours of labor ; the most efficient move- 

 ments; interest, enthusiasm and imitation; all 

 conditions favorable or unfavorable to work 

 or other forms of activity, including ventila- 

 tion, heating and lighting; food, alcohol, coffee 

 and tobacco; rest, play and sleep; posture and 

 strain in employments, conditions of fatigue 

 and safety, wherever the central nervous sys- 

 tem, the neuro-museular mechanism and the 

 senses are concerned. 



I am less sanguine in regard to our power 

 to alter the constitution of individuals, but we 

 can at least safeguard psychology from false 

 claims, and it may be that the child and even 

 the adult may prove plastic under the right 

 conditions. The savage could not imagine 

 turning iron into steel, still less turning steel 

 into a cantilever bridg«. Schools, churches, 

 the press, the family, customs, laws, govern- 

 ments, are indeed all means to control and di- 

 rect behavior. Their success in altering in- 

 dividuals has been but modest, and it is by no 

 means certain that psychology as a science can 

 accomplish much more than the Book of 

 Proverbs to improve the situation. Perhaps it 

 can do something, especially in the way of the 

 elimination of futile and harmful methods, 

 and a generation of research by a thousand 

 able men might contribute results of immense 

 value, measured either economically or in 

 terms of human welfare. At present, however, 

 and perhaps always, we can do more to alter 

 the environment and to place individuals in 

 situations where their reactions are what we 

 want than we can to alter individuals. For- 

 tunately all men are not bom equal ; it is both 

 undesirable and impossible to make them 

 equal, or indeed' to alter fundamentally the 



