Sarah Bechtel

she/her

Education: Majoring in psychology

Mentor: Alexandria Zakrzewski, Ph.D.

McNair Project: Harmonic Layering and Pitch Chroma Differences

Is detecting differences in pitch and complexity an inherent or learned skill? Auditory studies created 2 tools to assist in measuring to what degree these skills are inherent: pitch chroma (PC) and harmonic layering (HL). PC refers to the relationship between octaves and the notes within them. HL is the practice of layering pitches which are harmonies (defined by music theory). Studies have found that the brain pairs octaves together, but won’t pair complex pitches (Briley et al., 2013) (Regev et al., 2019). A study examining Zebra Finches and humans found a ‘tipping point’ around the 5th layer (Lohr & Dooling, 1998). It was hypothesized (1) musicians will perform better than non-musicians, (2) participants will be more sensitive to pitches with more space between pitch heights, and (3) participants will respond adversely to HL under 5 onthe 12-point layering scale. Participants heard a sequence of pitches examining their ability to decern differences in PC. Participants then heard sounds examining their ability to decern differences in harmonic layers. PC was detected with 89% accuracy amongst all groups, however the difference in performance between musicians and non-musicians was insignificant, F(1, 38)0.45, p = .51. Harmonics were detected accurately from layers 2-8, but declined around layer 5; an ANOVA showed this interaction with the layers was significant, F(11, 418) = 4.56, p < .001. This suggests there is more to examine via EEG as to why layer 5 dips, why layers 2-8 are discernible, and why all participants processed PC adequately.