Why can I remember a long Bach fugue, but forget where I put my keys?* Although we regularly curse our memories, our amazing capacity for memorising music indicates that we can actually retain and reproduce an enormous amount of information with incredible accuracy.
Having a good memory requires two things – good encoding (i.e. storage and organisation of information) and efficient retrieval (i.e. fast and accurate access to relevant information when required). We all carry vastly more information around in storage than we can possibly access at any one time – words, dates, facts, places, friends, events, preferences and dislikes. Everyone has experienced that exasperating tip-of-the-tongue scenario, when we’re sure of the answer but can’t quite produce it when asked. Some unlucky folks have a musical equivalent – sitting down at the piano in full view of an expectant audience, knowing all the notes of a Chopin etude but being utterly unable to recall how to actually play it at that moment in time!
How is music encoded and retrieved from long term storage? I previously wrote about the role of short term working memory in music, which provides temporary storage and manipulation of information in real time. But a well memorised piece of music is encoded in long term memory (LTM), which provides storage of information for long periods of time, ranging from hours to decades. Importantly, different types of information is stored separately and recalled differently from long term memory:
- Explicit (declarative) memory is consciously recalled. This includes:
- semantic memory of knowledge, words and facts (e.g. Beethoven is a classical composer who wrote the Moonlight Sonata)
- episodic memory of autobiographical events (e.g. I played Beethoven’s Moonlight Sonata in a cold concert hall in Bristol when I was a teenager).
- Implicit (procedural) memory is unconsciously recalled. This includes memory for skills (e.g. how to play the C# minor arpeggio at the start of Beethoven’s Moonlight Sonata).
There are a number of different descriptions of how memories are organised in LTM. Of particular relevance to music is the use of hierarchical schema which provide an organised network of connections between chunks of memorised information. It’s easier to remember new information that’s consistent with existing schematic knowledge – a phenomenon known as consistency bias – which explains why most people find memorising tonal music easier than atonal (and why two people can have radically different memories about the same event). Memories in the network can be accessed via retrieval cues – snippets of information that are linked to a particular memory. Retrieval cues are most effective when they are encoded at the same time as the memory itself, such that retrieval becomes essentially a progression from one or more retrieval cue to the target memory.
Aaron Williamon at the Royal College of Music in London has written extensively about the role of hierarchical retrieval structures in memorising music. In a fascinating analysis of 22 pianists of differing levels of skill (ranging from ABRSM Grades 1-8), he found that all pianists used structure during encoding and retrieval of a new piece of music, and that the shared tendency to both start and stop at structural bars during practice increased with skill level . The pianists were essentially using key structural bars as retrieval cues for a whole section of the piece. Excitingly, taken together with Roger Chaffin’s detailed case study of a concert pianist learning a new piece, this demonstrates that there is a continuity between the memory strategies of experts and novices. Rather than being something exceptional, only attainable by the elite few, expert musical memory develops alongside musical expertise itself.
Neuroimaging has also been used to investigate the way in which musical information is stored and accessed from LTM. Groussard et al. used functional MRI to compare the neural activation that occurred in 20 musicians and 20 non-musicians who were asked to rate the familiarity of 60 melodies . As expected, a much higher proportion of the melodies were rated “extremely familiar” to musicians than non-musicians (85% versus 30% respectively), in whom the melodies formed part of both their semantic and episodic knowledge. Essentially, musicians were able to link the melodies to both perceptual and contextual details that the non-musicians lacked. Moreover, although familiarity increased activity in an extended network of regions in the brain in both groups, significantly stronger activation was observed in certain areas in musicians including those involved with viso-spacial and autobiographical memory. They also observed a significantly higher density of grey matter in the left hippocampus of musicians, a region classically dedicated to memory. The authors concluded that the “data indicate that musical expertise critically modifies long-term memory processes and induces structural and functional plasticity”.
Clearly performing music from memory draws on every type of LTM – explicit semantic memory of the notes and structure of the piece, explicit episodic memory of prior performances or rehearsals, and implicit procedural memory of the skill required to actually play a piece. For a great summary of how musical memory works, and the interaction between working memory and LTM, here’s an excellent video from Victoria Williamson at Goldsmiths College in London.
*So, in answer my original question: I spent many many hours practising, analysing and learning my favourite Bach fugue (BWV 944) over a 6 months period. I embedded performance retrieval cues every few bars, to which I attended regularly through both physical and mental practice. I carefully considered which contrapuntal line to bring out and experimented with alternative dynamics and articulation throughout. When I perform it, I am conscious of my location on a mental map of the piece, and of past performances. In contrast, I threw my keys on a chair and put my bag on top without even a moment’s consideration! Perhaps this difference in focus is why memorising music provides such a meditative respite from the frenzied whirr of daily life.
 Groussard, M., La Joie, R., Rauchs, G. et al. When Music and Long-Term Memory Interact: Effects of Musical Expertise on Functional and Structural Plasticity in the Hippocampus, PLoS One 5 (2010); e13225
Baddeley, Eysenck & Anderson, Memory (Psychology Press, 2009)
Williamson, Online lecture about music and memory (free access)