Results of the World's Fair Hearing Tests 



By J. C. STEINBERG, H. C. MONTGOMERY, and M. B. GARDNER 



A hearing test for musical tones formed part of the Bell System 

 exhibit at the New York and San Francisco Fairs, and the test 

 records obtained have made possible a study of the hearing of a 

 large group of the United States population. The variation of 

 hearing acuity with age and sex is described in considerable detail. 

 Hearing is also related in lesser degree to other factors, such as 

 place of residence, economic status, and race, and these relations 

 are discussed. 



The data are applied to the United States population by indi- 

 cating certain allowances which should be made for differences 

 between the Fair groups and the population, particularly with 

 respect to distribution of ages and economic status. 



Accuracy of the test is discussed in relation to ability of visitors 

 to understand the test procedure, disturbing effect of background 

 noise, and calibration of the test equipment. 



Certain results of the survey are expressed in terms of ear canal 

 pressure and equivalent free field intensity, and on this basis a com- 

 parison is made with the results of other surveys of hearing. 



A criterion is given for deciding how much hearing should vary 

 from average before being considered abnormal. Application of 

 this criterion indicates, in the case of children, a suggestive simi- 

 larity between incidence of adenoid growth as reported in medical 

 surveys and abnormal hearing for high frequency tones. 



\T /"ITH the opening of the New York and San Francisco World's 

 ' ' Fairs in 1939, an opportunity became available for a survey of 

 hearing in a large group of the United States population. One of the 

 Bell System Exhibits consisted of a hearing test whereby visitors could 

 test their hearing for tones of musical pitch. At the end of the test, 

 each visitor was asked to permit an attendant to make a photographic 

 copy of his hearing test card so that a study of the records might be 

 made. Before making the copy, the attendant indicated by a check 

 mark whether the visitor was male or female, colored or white, and 

 to which of the five age groups, 10-19, 20-29, 30-39, 40-49, or 50-59, 

 she judged him to belong. In all, some 550,000 photographic records 

 were obtained, and it is estimated that about 80 per cent of the visitors 

 who tested their hearing for musical tones cooperated in the survey. 

 A somewhat similar test for spoken words was also provided, but the 

 survey was concerned principally with the results of the musical 

 tones test. 



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