326 TITCHENER— PRODUCTION OF [Nov. 6, 



intensity (whistle louder). The number of confusions testifies that 

 these differences were not very dependable. 



The first series of experiments (July, 1914; Mr. Stephens, ex- 

 perimenter; Miss F. A. Bean, observer) consisted, as planned, of 70 

 mouth-sounds and 70 whistle-sounds taken in haphazard order. 

 Aside from the disturbances to which I have referred, the results 

 were: 



Whistle. Mouth. 



Whistle judged as 60 10 



Mouth judged as 25 45 



Mr. Stephens was at this date relatively unpractised, while Miss 

 Bean had had extended practice in the discrimination of whistle- 

 tones. The number of confusions (25 per cent, of the whole num- 

 ber of observations) was, evidently, large enough to warrant a con- 

 tinuation of the experiment. 



Other series, made by Messrs. Stephens and Carson with other 

 observers, brought results of the same numerical order; they need 

 not be cited. I pass at once to the two final series made (August, 

 1914) by Mr. Stephens. The first comprised two part-series of 50 

 tests, each composed of 25 mouth-sounds and 25 whistle-sounds. 

 The observer, Dr. W. S. Foster, knew the plan of the investigation, 

 had himself tried to reproduce the whistle-tone by mouth, and had 

 had recent and unusually extended practice in the discrimination of 

 whistle-tones. The percentages of confusion were : 



Whistle judged as mouth 18 



Mouth judged as whistle 20 



or an average confusion of 19 per cent. 



In the second series, two part-series of 50 tests were composed, 

 the one of 22 whistle and 28 mouth sounds, the other of 28 whistle 

 and 22 mouth sounds. The observers. Dr. E. G. Boring, Dr. L. D. 

 Boring and Dr. M. E. Goudge, sat together for the experiment. 

 Dr. E. G. Boring had had a good deal of practice with the whistle, 

 and the other observers had performed the regular laboratory ex- 

 periments in which it is employed. All three were, however, given 

 special practice (with knowledge) in the discrimination of the stimuli 

 now to be used. The percentages of confusion were : 



