Wait… There Are 33 Senses?

You read that right! Researchers have concluded that there could be 33 or even more!

As occupational therapists (OT), we are all about the senses. Did you know that there are more than five senses? OTs actually consider eight sensory systems that work together in your body: Vision, auditory, tactile, olfactory, gustatory, vestibular, proprioceptive, and interoceptive. (check out SS blog on the 8 senses to learn more!)

Research shows there could be up to 33 senses (Durie, 2005). However, that depends on what you consider a body’s sense. The diagram (right) illustrates the different levels of senses considered as ‘established’ senses, and those being a more radical interpretation of the senses.

The Research

(Durie, 2005)

The leftmost orange column of the diagram, published by Bruce Durie (2005), illustrates the ten senses welcomed by societal standards, healthcare professionals, and others. These senses include vision, hearing, taste, touch, smell, interoceptive (precisely the purpose of one’s blood pressure), mechanoreceptive, balance, temperature, and pain. Many of these we have heard of, but what is mechanoreceptive? Simply put, the body can detect and respond to stimuli like touch, sound, or environmental change (Dijkgraaf, 2022). 

Exploring more of the body’s senses, neurologists and other researchers have detailed a more specific set of accepted senses. In the middle red column, the accepted senses are deeper classifications within the body’s basic senses that we all already know. 

• Vision: The ability to detect different light levels, colors

• Taste: The body can identify salts, sweets, sours, bitters, and umami flavors within different foods

• Mechanoreceptive: One’s sense of kinaesthesis (the ability to feel movements of the limbs and body) and proprioception.

• Temperature: The sense of hot vs. cold

• Interoceptors: The sense of one’s blood pressure beating, oxygen level content in the body (have you ever felt “lightheaded”?), cerebrospinal fluid pH (think about a headache, so when you sit up, the headaches are worse and improves when you lie down). It may be associated with light sensitivity, nausea, neck stiffness), Plasma osmotic pressure (when you are thirsty), artery-vein blood glucose difference (the sense of hunger), and lung inflation (breathing or feeling a “tight chest”)

• Along with the already discussed senses, hearing, smelling, touch, pain, and balance (within the mechanoreception category).

Why So Many?

The body's main sensory systems are the five basic senses we learn as a child. The categories are linked because of the body’s organs they are attached to (Durie, 2005; Dorothy, 2014). Durie (2005) explained that the body feels many more senses than just the basic five. He provides an exercise for the readers: imagine you are on a rollercoaster, zipping through the sky- do you think you are only experiencing the sense of taste, touch, sound, smell, and sight?

Probably not, and that is why there are many more senses the human body feels. Each of our body’s organs contributes to the process and facilitation of the sensations within the human body (Durie, 2005). When analyzing our body’s organs further, it is evident that different parts of each organ produce varying skills related to senses (Durie, 2005; Dorothy, 2014). For example, the sense of vision can be broken up into two parts of the body’s organ: the eye. The eye's lens controls the amount of light that seeps past your eyes to your retina (National Eye Institute, 2022). The cones in the eye’s retina control and perceive the wavelengths and then code them into colors for the human brain to understand (Mukamal, 2017). The important distinction of the different parts of the body’s organs allows us to see the variety of senses within the primary five.

Why Does This Matter?

Different senses work separately and together. For example, a child with an impaired sense of proprioception but good vestibular skills may have smooth handwriting skills (vestibular) but often break their colored pencils or crayons when using them due to pushing too hard (proprioception). Even though the child has a strong mechanoreceptor overall, their lack of awareness of the needed force on the pencil causes them challenges. That is why it is essential to understand what each of the body’s senses can do and how they work together. Another way the body’s senses can clash is when you feel car sick (check out SS blog on Car Sickness to learn more!)

Our body’s senses work together in many ways, overlapping responsibilities and roles and compensating when one sense is impaired. It is essential to understand that even though our body can use up to or even more than 33 senses, we need all of them to function cohesively.

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References

Dijkgraaf, S. (2022, August 9). Mechanoreception. Britannica.  https://www.britannica.com/science/mechanoreception/Maintenance-

of-equilibrium

Durie, B. (2005, January 26). Senses special: Doors of perception. New Scientist.  https://www.newscientist.com/article/mg18524841-

600-senses-special-doors-of-perception/

Dorothy. (2014, June 12). Not 5 but 33 senses. Arts and Humanities Research Council, AHRC. 

https://www.sciculture.ac.uk/2014/06/12/not-5-but-33-senses/

Mukamal, R. (2017, June 8). How humans see in color. American Academy of Optometry.  https://www.aao.org/eye-health/tips-

prevention/how-humans-see-in-color

National Eye Institute (2022, April 20). How the eye works. National Institute of Health. https://www.nei.nih.gov/learn-about-eye-

health/healthy-vision/how-eyes-work#:~:text=The%20lens%20works%20together%20with,the%20light%20into%20electrical%20signals.