How we taste different colours

We’ve all heard that the first bite is taken with the eye but the link between our visual sense and our flavour perception may be stronger than you think. When I think of flavour perception, noses and taste buds primarily spring to mind. Sure, other factors such as texture, temperature and touch sensations play a part but taste and smell are the dominant senses here, right? Well, perhaps not. You only have to consider the insatiable public appetite for food pictures masquerading as cookbooks to see there is meat to the old adage we eat with our eyes. Charles Spence, the Oxford experimental psychologist who helped Heston Blumenthal develop some of his playful multisensory signature dishes, places vision right up there with smell, in flavour’s premier league, if you will. 'Half the brain is visual in some sense,' says Spence. 'This is, in part, why the colour of our food and drink can not only determine whether it is appetising but its flavour, too.'

It is often said that we have an inherent aversion to blue food because it appears so rarely in nature. Another popular theory is that we’re attracted to red food because it signals ripeness, sweetness and calories. But is this an innate preference? According to Chris Lukehurst, head of research at the Marketing Clinic, 'How colour affects appetite is inconsistent and contextual. Think about green food and you might picture fresh, wholesome, vitamin C sources or cucumber. Or perhaps wind-rip lettuce, your fruits.' However, if I talk to you about green meat, he says, 'your stomach probably turns.' It is interesting, though, that a dyed-blue steak will have the same effect, even if you know it’s perfectly safe. If you get people to eat it in the dark, says Spence, 'they think it’s normal, then you turn the lights up and show them the colour, some will get up and be sick straightaway.' Such is the powerfully aversive effect of food colour out of context.

As well as tasting the colour of what we consume, we can also taste the shade of its wrapping. Spence has tricked people into confusing salt and vinegar crisps with cheese and onion flavour merely by switching packets. 'Many of our subjects will taste the colour of the crisp packet, not the crisp itself,' he says. Our brains excel in picking up associations and using them as shortcuts. When the colour makes us expect something to taste a certain way, we’ll taste what we expect unless it’s shockingly different. Using multiple colours in sweets such as Smarties and M&Ms is a strategy to get you to eat lots of them. People will wolf down more from a mixed bowl than they will from a bowl full of their favourite colour. And a recent study from Cornell University showed that you’ll eat more, too, if your food colour matches the plate, while a contrast will have the opposite effect.

If you can’t see colours, you might expect your other senses to sharpen and compensate but blind people don’t taste or smell any more than anyone else. They are, however, generally better at naming smells, which most sighted people struggle with. So they may not be tasting more intensely but they can identify flavours better without visual cues. Not surprisingly, losing your sight can make eating stressful and it is thought to contribute to a diminished appetite in old age. But even losing the capacity to see colours can have adverse effects. In his book An Anthropologist on Mars, Oliver Sacks told the fascinating story of a man who experienced this after an accident. He found eating less pleasurable and started to choose black or white foods, or eat with his eyes closed. Following a discussion with Blumenthal, Spence and his team at Oxford did some research to discover who is the most easily influenced by the effects of colouring and found that those at the super-taster end of the spectrum rely less on their eyes. Whereas those with fewer taste buds, says Spence, 'will be more easily led astray or say, 'Yep, I see red therefore it’s sweet.'