Some synaesthetes 'hear' moving dots

Some synaesthetes 'hear' moving dots

WHAT is the sound of dots moving? Most can't say, but for those with a newly identified form of synaesthesia, "hearing" sights is the most natural thing in the world - and may make it easier for synaesthetes to recognise visual patterns.

Melissa Saenz at the California Institute of Technology in Pasadena was tipped off when a grad student saw her screensaver and asked: "Does anyone else hear that?" His experience had the hallmarks of synaesthesia, in which stimulation of one sensory pathway creates an experience in another. When Saenz circulated the "noisy" image via email, three more synaesthetes came forward.

Ordinarily, people are better at recognising patterns if they are auditory rather than visual. To see if hearing-sight synaesthesia might make people better at recognising visual patterns, Saenz and collaborator Christof Koch asked the synaesthetes and a group of controls to listen to or watch pairs of sequences in the same modality and say whether they were identical; half were and half weren't. Both groups were about 85 per cent accurate on the sound patterns, but while controls got only 55 per cent of the visual rhythms right, synaesthetes remained steady at 85 - and they reported later that they were indeed hearing the flashes as well as seeing them (Current Biology, DOI: 10.1016/j.cub.2008.06.014).

"You can't fake being better," says neuroscientist Jamie Ward at the University of Sussex, UK. Finding new types of synaesthesia is not uncommon, he says, and they often confer an advantage.

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