Consonance Preferences Within an Unconventional Tuning System

Recently, Bowling, Purves, and Gill (2018a), found that individuals perceive chords with spectra resembling a harmonic series as more consonant. This is consistent with their vocal similarity hypothesis (VSH), the notion that the experience of consonance is based on an evolved preference for sounds that resemble human vocalizations. To rule out confounding between harmonicity and familiarity, we extended Bowling et al.’s (2018a) procedure to chords from the unconventional Bohlen-Pierce chromatic just (BPCJ) scale. We also assessed whether the association between harmonicity and consonance was moderated by timbre by presenting chords generated from either piano or clarinet samples. Results failed to straightforwardly replicate this association; however, evidence of a positive correlation between harmonicity and consonance did emerge across timbres following post hoc exclusion of chords containing intervals that were particularly similar to conventional equal-tempered dyads. Supplementary regression analyses using a more comprehensive measure of harmonicity confirmed its positive association with consonance ratings of BPCJ chords, yet also showed that spectral interference independently contributed to these ratings. In sum, our results are consistent with the VSH; however, they also suggest that a composite model, incorporating both harmonicity as well as spectral interference as predictors, would best account for variance in consonance judgments.