Why you can 'hear' words inside your head

Why you can 'hear' words inside your head Alamy Sound appears to play an important role in how our brains process information to do with language, whether we hear it or not When we have conscious thoughts, we can often hear a voice inside our heads – now new research is revealing why. This simple fact immediately raises the following crucial question: what happens to the electric waves in our brain when we generate a linguistic expression without emitting any sound? We compared the shape of the electric waves characterising the activity in the Broca’s area with the shape of the sound waves, not just when speakers were hearing sound, but also when they were reading linguistic expressions in absolute silence – that is, when the input was not acoustic at all. Remarkably, we found that the shape of the electric waves recorded in a non-acoustic area of the brain when linguistic expressions are being read silently preserves the same structure as those of the mechanical sound waves of air that would have been produced if those words had actually been uttered. It is as if this unexpected correlation provided us with the missing piece of a “Rosetta stone” in which two known codes – the sound waves and the electric waves generated by sound – could be exploited to decipher a third one, the electric code generated in the absence of sound, which in turn could hopefully lead to the discovery of the “fingerprint” of human language.