One of the ways in which we are investigating individual differences in conscious experience is through advancing our understanding of synaesthesia. Synaesthesia offers an exciting opportunity to understand the human mind and brain across different levels of explanation: from genetics (it runs in families), to brain development (it emerges early in life), to brain functioning (as measured in fMRI) to conscious experiences and behaviour.

Our research at the Sackler Centre has focused on Grapheme-Colour Synaesthesia, a condition associated with additional conscious perceptual-like colour experiences for letters or numbers, which are automatically and consistently triggered by the presence of these stimuli.

In a recent study we trained ‘normal’ individuals on an intensive (5 week) visual training regime to investigate whether learning grapheme-colour associations could lead to additional synaesthesia-like experiences. We found that, following training, all of our subjects reported clear changes in their experiences that closely mirrored descriptions from actual Grapheme-Colour Synaesthetes.  These results highlight the plasticity of the brain and how it is possible for learning to influence perceptual content even in adults and show that within a relatively modest timeframe (19 hours) it is possible to cause drastic changes in conscious perceptual experiences.