'York', 'accept' and 'fax' all contain the 'k' sound and all taste of egg.

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SYDNEY: Some people can 'taste' a word before it is even spoken, according to a new British study.

They have a rare form of synaesthesia, or crossing of the senses, where taste is triggered by words. The finding, which is published today in the British journal Nature, suggests it is the meaning of the word rather than the word itself that can activate a given taste.

Synaesthesia is a rare involuntary condition in which the brain links two or more of the senses. Tastes may be perceived as shapes, or colours may be heard or smelled.

In their study, Julia Simner of the University of Edinburgh in Scotland and Jamie Ward of University College London, worked with so-called lexical-gustatory synaesthetes who experience taste sensations when speaking, hearing or reading words.

According to Simner, "They are not 'pure' tastes like sweet, sour or bitter, but rather fully fledged meals, like macaroni cheese with extra butter, or even specific parts of the meal, like the pastry crust of a pork pie or the filling from a vanilla cream doughnut."

For these synaesthetes, pictures can also elicit tastes, but only if the related word or its meaning has been retrieved. "For example, a synaesthete who walks into a crowded room is not overwhelmed by hundreds of tastes from the hundreds of objects … but rather, as soon as they start to think of those objects in linguistic terms, the tastes come," Simner said.

It was previously thought that the word itself must be perceived for a taste to follow. Simner and Ward tested this 'no word, no taste' hypothesis by seeing whether the meaning of a word alone, rather than its sound or appearance, could lead to a taste.

To do this, they gave synaesthetes a picture-naming task, in which images of unusual objects (including a platypus) were shown to induce a state in which volunteers were striving to name a target word.

They managed to create a 'tip of the tongue' state 89 times, and on 17 occasions this was accompanied by an anticipatory taste. In other words, despite being unable to find the word matching an image, a taste was still perceived.

In all cases this taste was the same as the taste that the given word normally generated. For example, one participant tasted tuna fish when the word castanets was on the tip of her tongue. When the actual word was spoken, she also experienced the taste of tuna.

"Taste sensations in these synaesthetes are therefore triggered by thinking of the word's meaning, rather than by its sound or spelling," the authors reported. The results suggest that in synaesthesia, the perceptual experience - in this case taste - is one component of the brain process of linking meaning to words.

The authors believe these pathways may operate in everyone, but are exceptionally active in synaesthetes. For example, functional magnetic resonance imaging (fMRI) has shown that merely imagining a taste can activate areas of the brain associated with taste in non-synaesthetes.

According to Simner, there is still much to learn about synaesthesia, including its cause, its prevalence in children and what range of subtypes exists. And while the flavours of some words can be explained by the fact that they correspond to foods or rhyme with food words, others are a complete mystery.

"For example, for one synaesthete, words containing the sound 'k' are significantly likely to taste of egg - and it doesn't matter how the word is spelled. York, accept and fax all contain the 'k' sound and all taste of egg. Words containing 'f' are likely to taste of sherbet," report the researchers.