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The memory of noise: Auditory illustrations

[version française]

This first example is just a noise (click on the image to listen to it, ideally over headphones). A noise is simply a sequence of random numbers. All noises sound more or less like 'shhhhhhhh'.
But our perception of noises can be changed by memorizing them. This example was formed by repeating an identical snippet of noise twice per second. If you hear a regular rhythm in the noise, then you have learnt the snippet, which was formed from 22050 random numbers.
This last example is formed from a single repetition of another snippet of noise. When you first hear it, you probably just hear 'shhhhhh'. However, if you listen to it several times, you might start to pick out the repetition. If so, then you have learnt it from scratch.

The article describes an experimental procedure that was slightly different, in that the listeners who took part in the experiment didn't know that there was any noise to learn, but a noise was presented, just occasionally, throughout the experiment. We showed that listeners still learnt the noise. More than that, their learning was rapid, robust, and it lasted for several weeks. So it seems that there is a mechanism for auditory plasticity that is remarkably effective at allowing us to identify and memorize sounds which are repeated in our acoustical worlds.

Reference : Agus, T.R., Thorpe, S.J., & Pressnitzer, D. (2010). Rapid formation of robust auditory memories: Insights from noise. Neuron 66: 610-618.


[Equipe Audition] [CNRS] [LPP Paris 5] [ENS] [DEC]