Why do people hear colours and taste words?
Credit: iStockPhoto
SYDNEY: Synaesthesia - a neurological rarity in which two or more senses are connected - actually improves a number of traits such as memory and colour-processing, and could be a tool for understanding how the 'typical' brain works.
Synaesthesia is a condition that involves the production of a sense impression, such as the smell of daisies, by stimulation of another sense, such as seeing a river. It is present in 2 to 4% of the population and the majority of synaesthetes have experienced it since childhood.
A new paper published in PLoS Biology today suggests that synaesthesia is an authentic and repeatable phenomenon, and the cross-activation between different sensory brain regions may have evolutionary benefits.
"I had been interested in synaesthesia since I discovered in college that one of my friends was a synaesthete," said co-author David Brang, a cognitive psychologist at the University of California, San Diego. "Synaesthetes often show enhanced sensory processing in primary sensory modalities, and possibly cognitive changes as well, such as increased incidence of synaesthesia among artists."
Heightened experience, no drugs needed
Brang's findings stem from a number of studies looking at how synaesthetes differ from the rest of the population. Previous studies showing that the phenomenon increases the connectivity in the synaesthaetes' brains still left the question open of how and why synaesthesia has survived evolution.
Brang and colleague Vilayanur S. Ramachandran, a neuroscientist also from the University of California, examined mounting evidence that synaesthesia has evolutionary benefits, such as creativity.
They suggest that synaesthetes rely on many of the mechanisms present in the brains of all individuals, but have enhanced connectivity - or more 'cross-wiring' - in their brain. The 'hidden agenda' of the synaesthesia gene may be that a more cross-wired brain would have a greater propensity to link seemingly unrelated ideas, said the researchers.
Synaesthesia is not associated with any disorder or negative conditions, and can be beneficial to the individual in certain ways, especially in regards to memory. In 2004, British writer and savant Daniel Tammet used his synaesthesia to memorise the 22,514 digits of pi.
