Sensory Gating and Improvisation

It is rather surprising how often psychologists inadvertently come up with  poetic terms to describe their discoveries. One such term in neuroscience is, ‘sensory gating’. When a human hears a sound their brain responds rapidly, peaking at around 50 milliseconds (P50). The minute electrical currents generated by that response can be measured and plotted onto a graph. The graph looks like this:

P50 waveform of sensory gating
P50 waveform

When the same sound keeps repeating, with a short gap of about half a second between, the height of the P50 peak progressively reduces, resulting in a flattening of the response curve. It is a strangely counter-intuitive concept:  the higher the level of sensory gating, the flatter the response curve.

‘Sensory gating’ is a kind of habituation effect. Some writers link this phenomenon to the theory of ‘fight or flight’. The brain, they claim, makes an involuntary response to any sound, evaluating it as a potential threat. When we hear the same sound several times, the curve begins to flatten, and the brain no longer perceives the sound as threatening.

Lower sensory gating

Although the vast majority of people exhibit similar levels of sensory gating, a small minority display reduced levels. Instead of becoming habituated, they respond to repeated instances of the sound with a similar intensity. Schizophrenics are one social group that have particularly low sensory gating. Their elevated anxiety is thought to constantly trigger the ‘fight or flight’ response. There is, however, another group of people who have also been shown to have lower levels of sensory gating: musicians.

I came across all this when, as a psychology technician. I was trying to learn how to implement electroencephalography (EEG) experiments. An ‘auditory response test’ was the simplest EEG experiment that I could try to do.


It was when I tested myself that I received a surprise. It seemed that I had a surprisingly low levels of sensory gating. I began to wonder if this was linked, not to any unacknowledged schizophrenia, but to my practice regime as a musician. Instead of practicing the scales, arpeggios or jazz patterns I should probably do, I often just wear headphones and improvise along to whatever I am hearing. You could call it intensive ‘ear training’, done on a daily basis.

I started to wonder: does improvisation, in particular, develop a specific attentiveness to sound, even to the extent that it can supress sensory gating?  Many orchestral musicians play written music and never improvise. Improvisers, by contrast, rely solely on their ability to  make an instant response to sound. Classical musicians could counter that they are equally responsive to the details of sound. They might highlight how they modulate their volume, tone, articulation and expression to the requirements of the music. Would sensory gating  be lower amongst improvisers than amongst orchestral musicians?


I haven’t found any studies that have examined this. I suspect that it might be true, but only a detailed, large-scale experiment could conclude that it was. A study of dancers, musicians and ‘lay people’ comes close. Dancers display the kind of reduced sensory gating that one might expect from improvisers.

Functional Growth

Hercule Poirot boasts about the number of ‘little grey cells’ associated with his powers of deductive reasoning. It is interesting that musicians can make a similar claim for their craft. Professional musicians  have enhanced ‘functional’ growth in those areas of the brain associated with listening and dexterity. Did this ‘growth’ develop as a result of practice regimes, or did it precede and condition their musical abilities? I can’t help wondering if we would discover a slightly different distribution of ‘little grey cells’ amongst dedicated improvisers?

What hapens next?

For a time, I contemplated the idea that I might do this research myself: after all, I know so many improvisers. However, time passed and I eventually stopped working as a psychology technician. So, if someone stumbles across this post who would like to discover the answer to these questions, but also has access to the appropriate research equipment, please do let me know. I suspect that volunteers would not be hard to find.

The Virus

I’ve just written a short story called ‘The Virus’. I won’t give away the plot, but it was influenced by seeing so many surfers at Carcavelos beach. The beach is very close to the small apartment where I live, and I often walk along it. My friend, Bill Young, had lent me a book, called ‘21 Lessons for the 21st Century’, by Yuval Noah Harrari. Some elements of the story were in response to Harrari’s writing.

I read that unknown writers, like myself, should try and get something in print before trying to get a novel published. The idea for this story popped into mind, unbidden, and within a day I had written it, although I kept polishing it for longer. I wanted to try and limit myself to 2,000 words, and it exactly tipped the scales at that wordcount.

There is a question, though, which I ask myself. Does playing improvised music develop your ability to intuit form and duration? I feel that it does, but I am interested in the opinion of other musicians. Of course, I have sat through many concerts of improvised music, where countless opportunities to reach a satisfying conclusion were passed over, only to end limply after an excruciatingly long coda on the road to nowhere. Nevertheless, I have been both a participant and an audience member at events which, magically, concluded with jewel-like perfection. Sometimes, concerts have ended abruptly, mid-sentence, guided by a strange collective logic that is impossible to fathom, but which makes absolute sense at the time.

What causes a group of improvisers to stop in complete synchronicity like this? One element, I think, is a sense of what the group expresses in the moments leading up to such an abrupt truncation. It also requires a shared sensibility, not just to duration or form, but to collectively intuiting that an odd fragmented resolution, at that precise moment, provides the more complete musical statement.

I can’t help asking myself, does this sensibility transfer to writing? When I was writing each episode or chapter of ‘Mirror Trick’ I had a similar sense of appropriate duration. This active feeling, however, was much harder to retain throughout the course of a whole book, written over many months. In contrast, the shorter form of ‘The Virus’ felt more like a melody, sustained over several pages, and ending with a twist. It was not like the ‘mid-sentence’ endings that you sometimes hear in free improvisation, but something oblique, with a retrospective logic, closer to the kind of resolution that you find in conventional music.

Of course, you can easily point out that I am comparing ‘apples’ and ‘pears’: that the one is a collective experience and writing, whether it be music or literature, is usually a solitary one. My question is, though, can the sensibility developed and nurtured by group improvisation be transferred and applied in a similar way, when working on one’s own, writing stories?