SCIENCE 



versely as the number. The result of the vots 

 can be conveniently shown by curves such as 

 are here repi-oduced. The middle cui*ve gives 

 the distri'bution of the 82 votes for the 100 

 psychologists, the vertical ordinaites repre- 

 sentdng the numl>er af votes, while the indi- 

 viduals are ranged serially along the hori- 

 zontal axis. Tlie bottom cui-ve :^hows the num- 

 ber of double checks for each individual, 

 namely, ithe opinion that he is one of the five 

 psychologis-ts whose work is the most im- 

 portant. The top curve represents the sum of 

 two votes, and the individuals are arranged in 

 order in accordance with this vote.-* 



As indicated on the curve and sliown on the 

 taibles (which it seems unnecessary in this place 

 to print) it wo and only two psj'^chologists were 

 included among the fifty leading psychologists 

 by unanimous vote of itJieir eighty-two col- 

 leagues. The psychologist at the bottom of 

 the fifty received 35 votes; three were given 

 for the psychologist who stands last in the 

 hundred. Sixty-two of the 82 voting include 

 among the five whose work has 'been most im- 

 portant the two psychologists who received a 

 unanimous vote for inclusion among the fifty 

 and 20 do not. Such differences in judgment 

 are legitimate and significant. Thus the psy- 



3 Similar results have been obtained in each of 

 the twelve sciences, the number of scientific men 

 ranging from 175 chemists to 20 anthropologists. 

 The returns, however, were most complete for 

 psychology, the writer being personally acquaint- 

 ed with nearly all psychologists and a second 

 request having been sent to those who did not 

 reply to the first. There were in all some 130,000 

 votes to be collected, counted and tabulated. For 

 the treatment of this material I am mainly 

 indebted to my daughter, Miss Psyche Cattell. 

 Dr. Dean R. Brimhall and Dr. Alexander Wedn- 

 stein have also assisted in the revision of the 

 material and in the computations. 



I am under very great obligations to Professor 

 Raymond L. Pearl, of the Johns Hopkins Uni- 

 versity, and to Professor H. L. Rictz, of the State 

 University of Iowa, for their kindness in reading 

 tlie manuscript of the paper and for the useful 

 suggestions that they have made. This acknowl- 

 edgement should not, of course, be construed as 

 involving responsibility on their part. 



chologist placed eleventh is held 'by 22 of his 

 colleagues to belong to the first five and by 21 

 not to belong to the gix)up of 50, and similar 

 conditions obtained for the one placed twen- 

 tieth. The names could be guessed by one 

 familiar with the situation. They are men of 

 distinction Avhose moi^ important work is by 

 some judged not to fall within the field of 

 psychology. 



The attiitude of those voting is of scientific 

 significance, for it measures ithe validity of 

 judgments. If we assume the average judg- 

 ment of the 82 psychologists to be nearly cor- 

 rect, the departure from this average measures 

 the competence of tlie individuals to form such 

 judgments. There do not appear to be group 

 differences dependent on distinction or age, 

 but individuals, as shown in the previous study, 

 differ in the ratio of about two to one. 

 There will be an extraordinary change in 

 our attitude toward political, social and busi- 

 ness problems when we learn to look upon our 

 observations, recollections, 'beliefs and judg- 

 ments objectively, measuring the probability of 

 their correctness and assigning probable errors 

 to them. 



The top curve represents the sum of the two 

 votes and the order there given is the one used. 

 A different weighting of the two votes would 

 not considerably affect the order. The vote for 

 the five leading psychologists in the main dis- 

 criminates only the positions of the men in the 

 upper quantile. In place of the douible vote 

 for the five and the fifty per cent, of the 100 

 psychologists whose work has the most merit, a 

 satisfactory dista-ibution might be obtained by 

 a vote for 25, or one fourth of the whole num- 

 ber. In view of the constant use of votes for 

 elections and decisions, the problems involved 

 deserve more complete investigation. 



A probable error can be found for tiie posi- 

 tions of the individuals by a method that was 

 apparently fii-st used by the present writer. 

 When eighty of those voting are divided into 

 ten gi-oups of eight each, we have the separate 

 votes of each of tliese groups and from their 

 variation the probable ea-ror of the average vote 

 can ibe calculated. Thus the psychologist No. L, 



