Traditionally, we have split perception up into different senses. There’s sight, hearing, touch, taste and smell.
This immediately throws up complications. What we think of as ‘taste’ is actually a combination of senses.
Taste can be used two ways. First, the literal definition: it is the detection of chemical stimuli in the mouth, and this is usually split into receptors for sweet, sour, bitter, salty and umami.
[The last of these five might surprise you: umami is the taste of deliciousness – the savoury taste of amino acids. And some researchers are suggesting that there are more basic tastes, including water and fat.]
But there is also the common use of ‘taste’, which refers to the experience we have when we put food or drink into our mouths. This involves a combination of senses. As well as taste receptors on the tongue and elsewhere in the mouth, we have the sense of touch.
When we put things in our mouth, we feel them through touch receptors. Some flavours, such as the spicy burn of hot peppers, are felt through touch. We also use touch to localise the perception of taste: even though we are detecting qualities of food in our mouth from different locations, including the nose, we attribute the properties we experience to where the food or drink is in our mouth.
This makes us think that we are tasting with our tongue, when actually we are ‘tasting’ in lots of places, but the read-out is projected onto where the food or drink is present.