How we smell and taste

A recent article in the Guardian -- "What makes eating so satisfying?" -- summarized some of the research on how the brain and sensory organs work together to create flavor and enjoyment in eating and drinking. This fit very well with my recent project to learn more about human responses to aromas and smells as I have been writing here.

The author had several things to say about the complex pleasure of smelling and tasting wine.When you sniff a wine, the article points out, you perceive the most volatile aromas first, followed by those that are stirred up when you swirl the contents of your glass.

From the article: With wine, it is easy to confuse the two separate
entities of taste and smell. Photograph: David Levene 

The complexity of the taste receptors on the tongue isn't quite what one learned in the past: the old "map" of taste buds has been superseded by recent research, says the Guardian. "The current consensus is that tastebuds all over the mouth carry receptors for all the basic tastes, it's just that there are higher concentrations of those four tastes in their designated areas."

The following example illustrates the article's point that perceptions of flavors in fact reside in the brain and on memories and learned reactions, citing Professor Barry Smith of London University's Centre for the Study of the Senses:

It is easy to confuse the two separate entities of taste and smell, and the latter holds great sway over how something will taste when it reaches your mouth. For example, westerners associate the aroma vanilla with sweetness (which is a taste – we can't actually smell sweet) so strongly that if vanilla is added to food, we'll think it tastes sweeter than it really is. But connections such as this are, adds Smith, "learned by the brain, not by you". If you are given a drink that has traces of sugar and vanilla that you wouldn't detect if they were on their own, the two together will taste sweet to you. Unless you're from Asia, where vanilla tends to be associated with salty food. 

The role of the brain in creating flavor is the subject of an entire book that I read in the course of my project: Neurogastronomy: How the Brain Creates Flavor and Why It Matters by Gordon Shepherd. The connection made me find this example especially interesting.

Enjoyment of food also depends on visual cues, especially color, and on the sounds one hears while eating, says the Guardian:

In 2008, the Oxford professor Charles Spence won the Ig Nobel prize for proving the importance of noise when eating crunchy snacks. The study showed that people think Pringles "taste" stale when they're less crunchy, even though the taste and smell remain normal. He then put headphones on his munching participants, amplifying the sounds of their own crunching. The louder the crunch, the fresher and crisper the Pringles were reported to be. This is why, says Smith, "they make bags of crisps so noisy, to get the brain to think: fresh fresh fresh." 

Quite a fascinating article!