Dr Tudor Popescu | The consonances we hear, the music we imagine: Expectation as a two-way street

What makes our experience of music possible – and effortless – is an intricate puzzle of cognitive processes, involving a subtle interplay of what psychologists refer to as bottom-up and top-down components. The key concept of expectation can be construed at the centre of a complex feedback loop between these components, relaying information in both directions, and at different time scales. This framework holds not just for music we hear (an exogenous/bottom-up process) but also for music we create in our minds (endogenous/top-down). One mode of acquiring musical knowledge is implicit learning, which gradually gets to shape our sensory preferences, e.g. for certain combinations of simultaneous notes over others (consonant over dissonant chords – or indeed, in some contexts, vice-versa!), and also our unfolding expectations relating to e.g. what musical event might come next. These expectations form the core of a set of intuitions that have been formalised as models of musical structure, most notably Schenkerian analysis. Such models can inspire quantifiable predictions about the temporal nature of our expectation – for instance, with regards to the moment in time when we feel a piece is "beginning to end". The sum of these intuitions endows us with a template that on the one hand enables us to make sense of music that we hear; but equally, also to (re)create music in our own minds – a process known as musical imagery, which shares commonalities with music perception not only at the cognitive level (e.g. both can be conjectured to stem from a single generative model) but also at the neuronal level. In this talk, I will describe three distinct studies from the Dresden Music Cognition Lab, that address – using behavioural and neuroimaging methods – individual elements of the expectation-mediated loop outlined above, namely (i) the (local) perception of consonance and dissonance; (ii) the (non-local) perception of hierarchical musical structures; and (iii) the role of harmonic function in imagined music. I will then attempt to integrate these findings into the larger questions of how expectation guides our listening and imagery of music, and how the brain is wired to make these processes run smoothly in the background. Keywords: Musical imagery, Schenkerian analysis, consonance and dissonance; decoding fMRI, multivariate pattern analysis, time series analyses.