Didn't you know? It's possible to see and feel the texture of sound. It's even possible to taste a color or to hear the sound of a smell. Seems strange? For 99% of the population these statements are false. However, what happens in the brain of the other 1%? Synesthetes really experience these situations, and it's not caused by an overactive imagination.

Synesthesia is a neurological condition affecting approximately 1 in every 100 people, characterized by stronger connections between the senses. The majority of synesthetes automatically associate a letter or numbers with a color, but a wide variety of different associations are possible. This is an involuntary reaction which persists over time, for example a synesthete automatically associates the color red with the letter A, and this association is repeated each time that the person sees or thinks of the same letter.

"One person reported that smells have certain shapes. For example the smell of fresh air is rectangular, coffee is a bubbly cloud shape and people could smell round or square," said Dr Goodhew.

The study led by Dr Stephanie Goodhew from the psychology department of the Australian National University examined the brain of synesthetes and people without the condition during an association exercise. The exercise analyzed the extent to which synethetes associated two words, which may or may not be semantically linked, like 'doctor' and 'nurse' or 'doctor' and 'table'. Unexpectedly, the research found that synethetes had much stronger mental associations between related concepts than people without the condition, regardless of the type of synethesia exhibited.

This indicates a stronger connection between different parts of the brain, and in particular those areas linked to language in the temporal lobe, and the interpretation of color in the occipital lobe. Essentially this means that a visual stimulus, such as reading a letter, simultaneously activates the brain area linked to reading, and the brain area which interprets color.