You Don’t Have Just Five Senses – New Research Suggests Humans May Have up to 33

Human perception is multisensory, with dozens of interacting senses shaping how we experience taste, movement, balance, and the world around us.

Neuroscientists increasingly treat perception as a distributed system, where multiple sensory channels continuously negotiate a single, coherent reality. Because those channels interact, changing one input, sound, smell, motion, can quietly reshape what you think you’re feeling or tasting.

Spending hours focused on screens can make us forget about senses beyond sight and sound, even though they never switch off. When we pay attention, we notice the contrast between rough and smooth surfaces, tension building in our shoulders, or the softness of a piece of bread in our hands.

Daily routines are filled with these quiet signals. In the morning, there is the sharp tingle of toothpaste, the sound and pressure of water in the shower, the scent of shampoo, and later the familiar smell of freshly brewed coffee.

Aristotle famously described five senses, but he also believed the world was made of five elements, an idea we no longer accept. In the same way, modern science now suggests that human perception relies on far more than just five senses.

Our experience is deeply multisensory

Much of what we experience is deeply multisensory. Seeing, hearing, smelling, and touching do not happen in isolation. Instead, they unfold together, blending into a single, continuous awareness of both the world around us and our own bodies.

What we feel affects what we see, and what we see affects what we hear. Different odors in shampoo can affect how you perceive the texture of hair. The fragrance of roses makes hair seem silkier, for instance.

Odors in low-fat yogurts can make them feel richer and thicker on the palate without adding more emulsifiers. Perception of odors in the mouth, rising to the nasal passage, are modified by the viscosity of the liquids we consume.

Humans have many more senses than assumed

My long-term collaborator, professor Charles Spence from the Crossmodal Laboratory in Oxford, told me his neuroscience colleagues believe there are anywhere between 22 and 33 senses.

These include proprioception, which enables us to know where our limbs are without looking at them. Our sense of balance draws on the vestibular system of ear canals as well as sight and proprioception.

Another example is interoception, by which we sense changes in our own bodies such as a slight increase in our heart rate and hunger. We also have a sense of agency when moving our limbs: a feeling that can go missing in stroke patients who sometimes even believe someone else is moving their arm.

There is the sense of ownership. Stroke patients sometimes feel their, for instance, arm is not their own even though they may still feel sensations in it.

Taste, smell, touch, and balance intertwine

Some of the traditional senses are combinations of several senses. Touch, for instance involves pain, temperature, itch, and tactile sensations. When we taste something, we are actually experiencing a combination of three senses: touch, smell, and taste – or gustation – which combine to produce the flavors we perceive in food and drinks.

Gustation, covers sensations produced by receptors on the tongue that enable us to detect salt, sweet, sour, bitter and umami (savory). What about mint, mango, melon, strawberry, and raspberry?

We don’t have raspberry receptors on the tongue, nor is raspberry flavor some combination of sweet, sour, and bitter. There is no taste arithmetic for fruit flavors.

We perceive them through the combined workings of the tongue and the nose. It is smell that contributes the lion’s share to what we call tasting.

This is not inhaling odors from the environment, though. Odor compounds are released as we chew or sip, traveling from the mouth to the nose through the nasal pharynx at the back of throat.

Touch plays its part too, binding tastes and smells together and fixing our preferences for runny or firm eggs, and the velvety, luxuriousness gooeyness of chocolate.

Sight is influenced by our vestibular system. When you are on board an aircraft on the ground, look down the cabin. Look again when you are on the climb.

It will “look” to you as though the front of the cabin is higher than you are, although optically, everything is in the same relation to you as it was on the ground. What you “see” is the combined effect of sight and your ear canals telling you that you are tilting backwards.

Research reveals how senses shape behavior

The senses offer a rich seam of research and philosophers, neuroscientists and psychologists work together at the Centre for the Study of the Senses at the University of London’s School of Advanced Study.

In 2013, the center launched its Rethinking the Senses project, directed by my colleague, the late Professor Sir Colin Blakemore. We discovered how modifying the sound of your own footsteps can make your body feel lighter or heavier.

We learned how audioguides in Tate Britain art museum that address the listener as if the model in a portrait was speaking enable visitors to remember more visual details of the painting. We discovered how aircraft noise interferes with our perception of taste and why you should always drink tomato juice on a plane.

While our perception of salt, sweet, and sour is reduced in the presence of white noise, umami is not, and tomatoes, and tomato juice is rich in umami. This means the aircraft’s noise will taste enhance the savory flavor.

Everyday illusions expose sensory complexity

At our latest interactive exhibition, Senses Unwrapped at Coal Drops Yard in London’s King’s Cross, people can discover for themselves how their senses work and why they don’t work as we think they do.

For example, the size-weight illusion is illustrated by a set of small, medium and large curling stones. People can lift each one and decide which is heaviest. The smallest one feels heaviest, but people can them place them on balancing scales and discover that they are all the same weight.

But there are always plenty of things around you to show how intricate your senses are, if you only pause for a moment to take it all in. So next time you walk outside or savor a meal, take a moment to appreciate how your senses are working together to help you feel all the sensations involved.

Adapted from an article originally published in The Conversation.

Disclosure: Barry Smith has received funding from the Arts and Humanities Research Council for his research on multisensory experience, which underpins the creation of this exhibition on the senses.

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