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Do we all have the capacity for synaesthesia?
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Learn to see sounds and hear colours David Robson
DO WE all have the capacity for synaesthesia or is the brain’s ability to blend senses bestowed on a select few at birth? It now seems it could be a mixture of the two. Synaesthesia seems to underpin some savants’ enhanced memory and numerical skills. The hope is that a better understanding of its origins could help to explain savant abilities – and perhaps even shine some light on whether we are all capable of attaining them. The condition is thought to arise when extra connections in the brain cross between regions responsible for separate senses. To see if genes play a role in building or maintaining these connections, a team led by Julian Asher at the University of Oxford took genetic samples from 196 individuals from 43 families, 121 of whom exhibited auditory-visual synaesthesia, meaning they “see” sounds. “When I hear a violin, I see something like a rich red wine,” says Asher, who is a synaesthete.
failed to see the digits when the background colour corresponded to the colour they associated with a number. Controls who had not been placed under a trance, but were instructed to attach a colour to each number, did not make this mistake (Psychological Science, DOI: 10.1111/j.1467-9280. 2009.02286.x). “It shows that even without hyperconnectivity in the brain,
“A cello is more like honey.” From their analysis, the team were able to pin down four chromosomal regions where gene variations seemed to be linked to the condition (The “Hypnosis may reactivate American Journal of Human connections that had been Genetics, DOI: 10.1016/j. suppressed by the brain, ajhg.2009.01.012). As one of the causing synaesthesia” regions has also been associated with autism, there may be a common genetic mechanism you can still have synaesthesia,” underlying the two, says Asher. says Cohen Kadosh. He says So if we are genetically disposed hypnosis may reactivate to develop synaesthesia, does connections that had been that rule out the possibility of suppressed by the brain. inducing the experience? To Julia Simner from the find out, Roi Cohen Kadosh from University of Edinburgh, UK, Imperial College London and colleagues hypnotised four volunteers so that they viewed numbers as having innate colours, known as grapheme-colour synaesthesia. The volunteers then looked at a series of coloured slides, some with a black digit in the centre and some without (see diagram). Like people with synaesthesia, roughly 80 per cent of the time the hypnotised volunteers
has further evidence that synaesthesia is not the result of neural connections fixed before birth. She studied 615 6 to 7-yearolds, eight of whom turned out to be grapheme-colour synaesthetes. Over the course of a year, these children gradually associated more letters with colours, showing that the ability developed with time (Brain, DOI: 10.1093/brain/awn292). So should we all attempt to develop savant-like abilities? “Synaesthesia is strongly linked to improved memory capabilities so it would definitely be a good thing to research,” says Simner. Asher is more cautious, stressing that synaesthesia is often distracting, for example, while reading or listening to a lecture. He hopes to develop a genetic test to diagnose children and warn teachers of potential difficulties. ■
Inducing synaesthesia Hypnosis can be used to test whether we all have a capacity for synaesthesia HYPNOSIS: Volunteers are hypnotised to associate a particular colour with a particular number, a form of synaesthesia In this case 2 is yellow
TEST: Volunteers are shown a black number 2, once against a yellow and once against a red background
RESULT: If hypnosis is successful, the volunteers see the 2 as yellow. This means they can’t see the 2 at all when it is shown against the yellow background, but can see it against the red background
1 2 3 4 5 6 1 2 3 4 5 6
2
2
2
2 14 February 2009 | NewScientist | 13
Learn to see sounds and hear colours David Robson
DO WE all have the capacity for synaesthesia or is the brain’s ability to blend senses bestowed on a select few at birth? It now seems it could be a mixture of the two. Synaesthesia seems to underpin some savants’ enhanced memory and numerical skills. The hope is that a better understanding of its origins could help to explain savant abilities – and perhaps even shine some light on whether we are all capable of attaining them. The condition is thought to arise when extra connections in the brain cross between regions responsible for separate senses. To see if genes play a role in building or maintaining these connections, a team led by Julian Asher at the University of Oxford took genetic samples from 196 individuals from 43 families, 121 of whom exhibited auditory-visual synaesthesia, meaning they “see” sounds. “When I hear a violin, I see something like a rich red wine,” says Asher, who is a synaesthete.
failed to see the digits when the background colour corresponded to the colour they associated with a number. Controls who had not been placed under a trance, but were instructed to attach a colour to each number, did not make this mistake (Psychological Science, DOI: 10.1111/j.1467-9280. 2009.02286.x). “It shows that even without hyperconnectivity in the brain,
“A cello is more like honey.” From their analysis, the team were able to pin down four chromosomal regions where gene variations seemed to be linked to the condition (The “Hypnosis may reactivate American Journal of Human connections that had been Genetics, DOI: 10.1016/j. suppressed by the brain, ajhg.2009.01.012). As one of the causing synaesthesia” regions has also been associated with autism, there may be a common genetic mechanism you can still have synaesthesia,” underlying the two, says Asher. says Cohen Kadosh. He says So if we are genetically disposed hypnosis may reactivate to develop synaesthesia, does connections that had been that rule out the possibility of suppressed by the brain. inducing the experience? To Julia Simner from the find out, Roi Cohen Kadosh from University of Edinburgh, UK, Imperial College London and colleagues hypnotised four volunteers so that they viewed numbers as having innate colours, known as grapheme-colour synaesthesia. The volunteers then looked at a series of coloured slides, some with a black digit in the centre and some without (see diagram). Like people with synaesthesia, roughly 80 per cent of the time the hypnotised volunteers
has further evidence that synaesthesia is not the result of neural connections fixed before birth. She studied 615 6 to 7-yearolds, eight of whom turned out to be grapheme-colour synaesthetes. Over the course of a year, these children gradually associated more letters with colours, showing that the ability developed with time (Brain, DOI: 10.1093/brain/awn292). So should we all attempt to develop savant-like abilities? “Synaesthesia is strongly linked to improved memory capabilities so it would definitely be a good thing to research,” says Simner. Asher is more cautious, stressing that synaesthesia is often distracting, for example, while reading or listening to a lecture. He hopes to develop a genetic test to diagnose children and warn teachers of potential difficulties. ■
Inducing synaesthesia Hypnosis can be used to test whether we all have a capacity for synaesthesia HYPNOSIS: Volunteers are hypnotised to associate a particular colour with a particular number, a form of synaesthesia In this case 2 is yellow
TEST: Volunteers are shown a black number 2, once against a yellow and once against a red background
RESULT: If hypnosis is successful, the volunteers see the 2 as yellow. This means they can’t see the 2 at all when it is shown against the yellow background, but can see it against the red background
1 2 3 4 5 6 1 2 3 4 5 6
2
2
2
2 14 February 2009 | NewScientist | 13