Similarity relations between groups of notes: Music-theoretical and music-psychological perspectives
Authors: Ockelford Adam 
Published: March 2011

The starting point of this article is Irène Deliège's essay on the similarity relationships that, it is claimed, lie at the heart of creating and cognising musical structure (2007): in particular (though not exclusively) relations that function internally within works, and which may be perceived implicitly or conceived explicitly. Initially, a music-theoretical tack is adopted, commencing from Arnold Schoenberg's concept of the musical “motive”,1 and his taxonomy of motivic transformations, which, he asserts, underpin musical coherence (1967). This and other classifications by the theorists Rudolph Ræti (1951), Jan LaRue (1970) and Wilson Coker (1972) are interrogated using the author's “zygonic” theory of music-structural understanding (Ockelford, 2004, 2005a, 2005b, 2006a), and, with reference to the music-psychological work of Mary Louise Serafine (1983), David Temperley (1995) and Bruno Repp (1997), a new, composite taxonomy is proposed, which sets out the forms of connection that can logically exist between one group of notes and another. This is illustrated with musical examples, which suggest (a) that similarity cannot be judged in isolation from the musical context in which it occurs (something that is modelled through an expanded version of Leonard Meyer's (1973) “formula of perceived conformance”); and (b) that similarity is likely to be judged differently between and even within subjects, depending on the listening style that they adopt. This will vary in general terms according to listeners’ musical beliefs and experiences, and specifically in relation to the attitudes and attention that they bring to bear on a given occasion. Hence it is concluded that there is not, and could never be, a universal metric of perceived musical similarity. How, then, does one explain the coherence of music as a communicative medium, which purportedly depends on a common understanding of relationships of similarity between composers, performers and listeners? It is surmised that composers intuitively or consciously endow their music with sufficient similarity for it to be recognisable and meaningful to listeners, even if some connections, particularly those functioning at a conceptual level, are missed or construed in unanticipated ways (Ockelford, 2004). The highly repetitive nature of music means that analysts too are able to identify not only those similarity relationships that seek to illuminate the compositional process or reflect or influence the way that listeners approach pieces, but also those correspondences that are deemed to be intrinsically noteworthy, without necessarily having any direct bearing on the musical experience. Clearly, this stance is at odds with music-psychological methodologies that tend to examine aspects of similarity perception that are common across a population. That is to say, different music-related disciplines (and even different approaches within disciplines) are likely to afford similarity a different ontological status. Zygonic theory offers a way forward: a conceptual framework that different epistemological modi operandi can potentially share.