The effect of scale and familiarity on the perception of music "dissonance"

Music is part of cultures all over the world and is entrenched in our daily lives, and yet little is known about the neural pathways responsible for how we perceive music. The property of "dissonance" is central to our understanding of the emotional meaning in music, and this study is a preliminary step in understanding how this property of music is perceived. Twenty-four participants with normal hearing listened to melodies and ranked their degrees of dissonance. Melodies that are categorized as "dissonant" according to Western music theory were ranked as more "dissonant" to a significant degree across the 9 conditions (3 conditions of scale: Major, Neapolitan Minor, and Oriental; 3 conditions of wrong notes: no wrong notes, diatonic wrong notes, and non-diatonic wrong notes). As expected, the familiar Major scale was identified as more consonant across all wrong note conditions than the other scales. Notably, a significant interaction was found, with diatonic and non-diatonic notes not perceived differently in both of the unfamiliar scales, Neapolitan and Oriental. This study suggests that the context of musical scale does influence how we create expectations of music and perceive dissonance. Future studies are necessary to understand the mechanisms by which scales drive these expectations.