Perception of isolated chords: Examining frequency of occurrence, instrumental timbre, acoustic descriptors and musical training

This study investigated the perception of isolated chords using a combination of experimental manipulation and exploratory analysis. Twelve types of chord (five triads and seven tetrads) were presented in two instrumental timbres (piano and organ) to listeners who rated the chords for consonance, pleasantness, stability and relaxation. Listener ratings varied by chord, by timbre, and according to musical expertise, and revealed that musicians distinguished consonance from the other variables in a way that other listeners did not. To further explain the data, a principal component analysis and linear regression examined three potential predictors of the listener ratings. First, each chord’s frequency of occurrence was obtained by counting its appearances in selected works of music. Second, listeners rated their familiarity with the instrumental timbre in which the chord was played. Third, chords were described using a set of acoustic features derived using the Timbre Toolbox and MIR Toolbox. Results of the study indicated that listeners’ ratings of both consonance and stability were influenced by the degree of musical training and knowledge of tonal hierarchy. Listeners’ ratings of pleasantness and relaxation, on the other hand, depended more on the instrumental timbre and other acoustic descriptions of the chord

Disclosure of sex when incidentally revealed as part of preimplantation genetic testing (PGT): an Ethics Committee opinion

© 2018 American Society for Reproductive Medicine Clinics may develop a policy to disallow selecting which embryos to transfer based on sex and choose to use only embryo quality as selection criteria. Clinics may also develop a policy to use randomization to select those embryos for transfer if more embryos suitable for transfer are available than can be transferred. Earn online CME credit related to this document at www.asrm.org/elear