Taste perception

Taste receptors and taste buds

Also known as gustatory cells, they are the sensory receptors that detect the chemical molecules that enable taste. They are located within the taste buds. It is estimated that most people have about 8000 to 10 000 taste buds. The number of taste buds peaks in early childhood and gradually declines during adulthood. Most of your taste buds are located on your tongue, however they are also found under the tongue, on the roof of the mouth, on the sides of the mouth, and at the back of the mouth on the upper part of the throat behind the nose. On the tongue, the taste buds are located within the thousands of small bumps called papillae that you can see and feel on the surface. Each taste bud consists of a cluster of 50-150 taste receptors.

Papillae

An individual papilla may hold one or more taste buds. Not all papillae contain taste buds and taste receptors. Those found around the sides and at the front of the tongue contain taste buds, whereas those found mostly in the centre of the tongue do not have taste buds. Other functions of papillae include: pain receptors that respond to hot and spicy sensations, help break down fats, and others are touch receptors that contribute to the perception of food texture.

Culture

Generally, we like and prefer tastes we grow up with. This tends to persist in childhood, but most people will eventually try 'new tastes' when presented with the opportunity. Your taste can be influenced by people you know growing up, or even in the womb due to what your mother eats.

From mouth to brain

Our perception of taste begins with the physical stimulation of the taste receptor cells in the mouth. Stimuli that produce taste sensations are the chemical molecules that exist in what we eat and drink. Saliva dissolves the molecules, enabling the chemicals to stimulate our taste buds. It is not food or drink that can stimulate the taste buds. When taste receptors are stimulated, they convert the sensory input into signals that can be sent to the brain along neural pathways. The 'taste' pathways are cranial nerves which connect directly to the brain. Most messages travel to the brain along the facial cranial nerve. After initial processing by the thalamus, the sensory information is relayed to the gustatory cortex for interpretation. Taste alone does not affect how much you like a certain food or drink so the information is combined with other sensory inputs such as sight and smell.

Influences on taste perception

Our taste preferences are determined by perceptions that are shaped by the complex interaction of biopsychosocial factors. These include: Age (bio), Genetics (bio), Perceptual set (psycho) and Culture (social)

Genetics (supertasters)

People vary in their ability to taste. One reason is that genetic differences make us more or less sensitive to the chemical molecules in different foods. Our genes can therefore influence how sensitive we are to bitterness, sweetness or any other tastes. American psychologist Linda Bartoshuk (2015) describes Supertasters as individuals who experience taste sensations intensely. She found that supertasters find tastes to be 2 to 3 times as intense as do other people. Supertasters inherit an unusually high number of taste buds.

Taste aversion

Sometimes we can develop a perceptual set that is so strong that the mere sight of the food can make us feel or be sick. This is where we expect that a taste experience will be extremely unpleasant., which usually means that we will avoid eating it. It is learned through past experience with a food, usually when having become ill after tasting or eating it.

Basic tastes

Sweet, sour, salty, bitter, unami

Tasting process

Taste pores on the surface of the tongue open into the taste bud, effectively connecting the surface of the tongue to the taste receptors within the taste buds. The connection is through fine gustatory hairs that extend from the taste receptors into the taste pores. These hairs come in contact with tastants. Tastants are the dissolved chemical molecules that can be tasted. The hairs stimulate their connected taste receptor cells to pass signals on to sensory neurons which transmit the messages to the brain.

Age

The ability to taste many substances is already well developed at birth. Newborns are programmed to like sweet tastes. As we mature, we develop a tolerance and even a liking for more bitter tastes. Research also shows that children are much more responsive to taste than adults. One explanation is that they have more taste receptors than adults. We start to lose taste buds as we age. From the age of about 40, our taste buds do not regenerate as fast as they die,

Perceptual set

The way food is packaged and branded can also impact the way we perceive its taste.