Guthrie, E.R., Morrill, H. (1928). The fusion of non-musical intervals. Am. J. Psychol. 40, 624-625

In a recent number of this JOURNAL Brues published the results of an investigation of the fusion of non-musical intervals. A recent experiment in the University of Washington Laboratory resulted in a striking confirmation of his results by the use of a radically different method...

Reports on the discrimination of 'consonance' and 'dissonance' were obtained from 381 Os, and on 'pleasantness' and 'unpleasantness' from 372 Os...

It will be noted that there is no tendency for the high points of 'consonance' or of 'pleasantness' to coincide with the intervals of simple ratio, or with the 'musical' intervals of the equally tempered scale... The degrees of fusion indicated in the Washington experiment and in the experiment of Brues are in substantial agreement when differences in method are taken into account. In addition to using a different method of recording judgments, Brues worked with tones of another pitch range, from 256 v.s to 512 v.s.

... The curves obtained have a slight resemblance to the theoretical curvs of consonance worked out by Helmholtz for tones including several partials. They have no resemblance to the curve indicated by Helmholtz for combinations of pure tones...