According to this fascinating article, a lot of people with synaesthesia don’t realize others don’t see things as they do. Many can do amazing things that we ordinary people can’t. Have they evolved into a better form of human? Are you, or do you know, one of them?

Dr Simner studies synaesthesia – a condition caused by an unusually high number of connections between two areas of the brain’s sensory cortex, making two senses inseparable. Synaesthetes, as they are known, have experiences that might seem extremely strange to any non-synaesthete. The extra connections might be between the brain area that processes colours and the area that processes language.
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“One of the most common variants is called grapheme-colour synaesthesia,” says Dr Simner.

“People with this variant know the colour of letters of the alphabet. So they know that the letter ‘A’ may be red. But not just any red, it’s a certain shade of crimson. And B is turquoise-blue.”
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“If you want to define synaesthesia in a purely neurological sense, it’s just the predisposition to have extra pathways between areas of the brain,” says Dr Simner. “And we can see those connections.”