Published in The Hindu on December 8, 2011

Can people be trained to associate colour with sound? A unique experiment involving six chimps and 33 humans showed that some kind of an association can be built between the two.

Vera Ludwig, a cognitive neuroscientist at Charité Medical University in Berlin, Germany and colleagues from the Kyoto University first showed the chimps white or black boxes. They were then trained to select squares of the same colour on a screen. But each colour was accompanied by sound — high tones for white and low tones for black.

During the test, the scientists found that the animals correctly picked the colour 93 per cent of the time when the tone and colour were matched. The success rate fell sharply when they were reversed.

Though humans made very few mistakes while choosing the correct colour, the decisions were made more quickly when colour and sound matched!

Ludwig suggests that the synaesthesia or associations must have been present in the common ancestor of both species.

But a few scientists doubt if such associations are indeed true synaesthesia. The results were published recently in the Proceedings of National Academy of Sciences .