Do We Really Only Have Five Senses? Some Researchers List Up To 20

balance
How does your sense of balance fit in with the other senses? Pixabay Public Domain

The average person would readily agree that humans have five senses. If not, the massively popular film about a boy who can sense the paranormal would have gotten a lot more flak for being titled "The Sixth Sense." We rely on our abilities to see, hear, taste, smell, and touch every day, and these senses are all both vital and unique. But not everyone agrees that these five are all there is to our perception of the world around us. Some experts have called the senses into question — and proposed their own definitions that would cut them down to just three, or swell their number well past 1,000.

The principle of five human senses has ancient roots in Aristotle’s treatise De Anima. In the document, he discussed the nature of living things, devoting separate chapters to vision, hearing, touch, smell, and taste. Since then we have made strides in measuring and studying our senses, but a concrete definition still eludes us. Today, a sense is usually defined vaguely as a physiological faculty that allows humans to perceive stimuli. To get more technical, some argue that senses are “bodily systems consisting of a group of sensory cell types that not only respond to a specific physical phenomenon, but also correspond to a particular region in the brain,” according to Jessica Cerratini for Harvard Medicine.

If neurologists go by this more specific definition, they open the door for many more senses, such as the way we hold our body in space. Balance is controlled in large part by the vestibular system of the inner ear, often in conjunction with the visual system. Another sense many researchers consider is proprioception, the perception of body position. To experience this sense, close your eyes and touch the tip of your nose with your finger — you couldn’t see what you were doing, but you were able to sense where the end of your finger was and move it to your nose.

Some experts take this liberal definition even further, arguing that senses should be defined by our receptors, each type of which accounts for an entirely different sense. This would fracture the traditional senses into many more than five. Registering the warmth of an object would use a different sense than feeling its texture, for example, since our skin’s receptors for mechanical pressure, pain, and temperature are all different. Following this train of logic, our other senses would be split up as well — into more than 1,000 subsenses in the case of olfactory receptors.

On the opposite end of the spectrum, a very strict definition could cut out some of the big five we consider undeniable. Restrict the definition of sense to the types of physical stimuli, writes cognitive neuroscientist Christian Jarrett for the BBC, and we would have only three senses: mechanical, including touch, hearing, and proprioception; chemical, including taste and smell; and light, for vision.

It’s an interesting question for researchers to ponder, but does it really matter what we consider a sense? For people with sensory overload difficulties, this question is more than just a philosophical issue, according to child, parenting, and relationship psychotherapist Fran Walfish in Beverly Hills, Calif.

“Some children and adults have an exquisite sensitivity to loud noises (hearing sense) or tactile sensation (touch),” Walfish, who is also the author of "The Self-Aware Parent," told Medical Daily via email. She explained that scratchy tags on garments or crooked sock seams can be torture for people with a tactile sensitivity. “Identifying and learning about our sensitivities and vulnerabilities allows us to protect ourselves from experiences and situations that leave us frustrated, misunderstood, angry, and frightened,” she added.

Walfish said she believes experts who list many senses — sometimes up to 20 — aren’t helping parents of children with these kinds of sensitivities; they’re only making a complex subject even more complicated. She does, however, think there’s room in therapy for senses other than the traditional five.

“Balance and judgement of distance between ourselves and another person should be considered as two additional senses,” she said, because they are two areas where many children and adults face challenges. Clinicians who recognize these senses could make better therapeutic decisions when working with those who have sensory difficulties. For those of us without these problems, getting in touch with our lesser-known senses could have endless benefits, too, from improving mindfulness to increasing athleticism.

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