In another interesting part of the book, you mention studies that have shown marked variations in taste between some individuals. In some of these studies people have been labelled "supertasters." How do their tasting ability and propensity differ from the rest of us?

This has to do, partly, with how many taste buds they have. One of my colleagues has shown there is a correlation between having a high number of taste buds and a propensity to be sensitive to bitter taste. The more taste buds you have, the more likely you are to be a supertaster, and it's caused by genetic differences. But keep in mind that this difference is specifically in the sense of taste. Taste contributes to flavour, but sometimes taste and flavour are used interchangeably, and they are not the same. There should be no ambiguity between "taste" -- which is sweet, salty, sour or bitter -- and "flavour," which is a combination of olfactory sensations, tactile sensations and taste.

What roles do texture and colour play in taste?

You can be really fooled by the colour of the food you are eating. I mention that you can fool people, and these include experienced wine tasters, into assuming that a white wine is a red wine, simply by dying it red. I think that's a very good example of how colour can be used to manipulate people. It's something that gives us expectations about the flavour of what we are going to eat, and it's very well understood by food companies -- a point that Eric Schlosser makes in Fast Food Nation. You can bet that food companies are studying the colours that kids like to see on boxes of cold cereal and cans of soda.

This might be pertinent, as Thanksgiving is coming right around the corner. What is "the buffet effect," and how does it relate to some of our instinctual eating behaviours?

The buffet effect, also known as the cafeteria effect, relies on the assumption that if you have only one food in front of you, you will stop eating when you are full. But if someone brings you another plate with a different type of food on it, you are likely to keep eating. And it can go on like this indefinitely. You will eat far more with a variety of foods at one sitting than you would if you were eating only one dish. Fast-food companies know this. They sell a series of things in addition to the Big Mac. Thanksgiving is a good example of how, with a dozen different dishes, we just keep eating and eating. It's a very real thing and people who are obese lack control over it.

Many parents tend to struggle at times with kids who are picky eaters. But in the book you discuss some of the ways in which taste and olfaction are relatively plastic. You mention that flavour preferences can change and young children can learn to enjoy certain types of foods from exposure. Do you have any advice for parents of picky eaters?

Well, I know from my own family experience that kids vary widely as eaters. And some aren't just picky eaters but will refuse almost all foods except for a very narrow few. For kids, eating often means putting something in their mouth for the first time. That first sensation of something in your mouth can be quite aversive at first. And a child is more likely to feel that certain foods elicit a sensory quality that is unpleasant. This is where understanding how the brain creates the sensation of food, with multiple senses contributing, means that a therapist could begin to assess which sensory system is affecting how a child feels about an aversive food.

A lot of the topics in the book made me think about my own personal relationship to food and taste. I don't know if you've ever experienced this, but sometimes I'll go to a restaurant and notice that although they have Heinz ketchup bottles on the table, the first taste will clearly determine that they've filled the Heinz bottles with an impostor brand of ketchup. It infuriates me, and I think it undermines exactly what you lay out in your book: that the human propensity for taste and olfaction is actually much more sophisticated than we might assume. Can you speak to this?

I haven't experienced that, but it makes sense. I think one of the simplest ways of giving more credit to smell in flavour is the simple nose-pinch test. You pinch your nose and put a piece of candy or food on your tongue and ask what the flavour is. With their nose pinched, most people will be able to tell that it tastes sweet and that is all. Once you un-pinch your nose, the whole flavour of the food is able to travel to the brain, and that is all due to smell. As the subject breathes out, air goes from the back of the mouth up to the nose. This is a simple experiment that you can do around your dinner table. It gives you a completely new appreciation of where your sense of flavour is coming from. People use their sense of smell to get more pleasure out of the food that they are eating.

[Tags: Food, Science and Tech.]