Think of a concept, taste it on your tongue

New Scientist, 22 November 2006

New insight into one of the most intriguing word-associated conditions may have been found, with the discovery that, for one type of synaesthesia at least, the meaning of a word is key to the sensation experienced.

For some people, the mere mention of a word can bring a very specific taste to the tongue. "Mountain" might elicit cold bacon, for instance, while "Michelle" might conjure egg whites.

People who experience this have a rare condition known as lexical-gustatory synaesthesia, and for many of them every word comes with an appended taste. For some, even when the exact word cannot be recalled, the taste of the word is there.

Synaesthetes tend to experience the same taste for words with similar sounds. In one subject, for instance, not only does the word "mince" call up a mince flavour, but "prince" and "cinema" do too. This suggests that the taste is somehow tied to the sound or the spelling of the word.

Tip of the tongue

Julia Simner at the University of Edinburgh and her colleague, Jamie Ward, at University College London, both in the UK, showed 96 pictures of obscure items such as a gazebo, a geisha or a metronome to six subjects with lexical-gustatory synaesthesia.

In all but one subject they managed to induce a "tip of the tongue" condition, where the person recognised the object but could not remember what it was called, what letter its name started with or how many syllables the elusive word had. The researchers found that these individuals could still identify what taste the item elicited. One woman, for instance, unable to come up with the word "gramophone", reported tasting Dutch chocolate, precisely the flavour that the word is associated with for her.

This shows that it is the meaning of the word - not the sound or spelling - that elicits the taste sensation in these people, Simner says. She suspects the associations begin in childhood.

Phil Merikle, at the University of Waterloo in Ontario, Canada, has carried out research with synaesthetes that experience numbers as colours. He found that those doing simple arithmetic can compute faster when they see the colour they associate with the correct answer. "It's the concept that elicits the synaesthetic experience," he agrees.