You might think the common conception that we have only five senses is rooted in modern science, but that’s actually an ancient, incorrect idea put forth by the Greek philosopher Aristotle in a treatise called De Anima. There are definitely more than five, and the total can be surprising, as in the new book, ‘Super Senses: The Science of Your 32 Senses and How to Use Them’ (John Murray, 2021).
Thirty-two? Yes, scientists can count that many by looking at specific structures in the human body known as receptors; that is, cells and organs that can receive and translate signals from the environment.
Here are just a few of the senses beyond the basic five: sight, sound, smell, taste and touch.
Which way is up? Which way is right or left? The vestibular sense, a set of receptors in your inner ear, is activated whenever you move your head. It’s also activated by the downward force of gravity, giving you a sense of where you are: your grounding. At the most basic level, it allows you to balance.
The vestibular sense begins to decline at about the age of 40 (Bermudez et al., 2016). What people typically call “out-of-body” experiences, when you might feel you’re on the ceiling looking down at your body, can come with migraines, epilepsy attacks and in response to trauma. They may be a sign of a vestibular disorder (Lopez et al., 2017) or something else we don’t yet understand.
As with most body systems, the vestibular sense responds to being used. Anything that challenges your balance, like these exercises, will help build or at least maintain your vestibular sense.
If you extend your arm above your head, you don’t actually need to look at your arm to know that it’s above your head. You have a sense of your body occupying space, and the positions of your various appendages. Proprioception enables you to touch your finger to the tip of your nose with your eyes closed, or climb steps without looking at them.
The receptors for proprioception are in your muscles and joints, which send information to your brain. This sense is activated any time you push or pull on an object. A child who uses too much force when writing or coloring, for example, may have a proprioception problem (Kiley, 2021).
You can improve your proprioception by walking on a balance beam or stepping stones, or playing any active sport such as football. Try moving around your home with your eyes closed (Young, 2021). One study found that doing a series of demanding proprioception exercises while using another skill, like balance, boosted working memory—more so than a yoga class or classroom lecture (Alloway, 2015).
I live in New York City, and it’s still exciting to me to see how New Yorkers move through crowded spaces and don’t smash into each other. Both the vestibular sense and proprioception come into play in what the urbanist Jane Jacobs called our sidewalk “ballet.” Smart phones distract us, yet the ballet continues.
Nerve cells just below the skin are specifically configured to pick up temperature. But like everything associated with the body and its perceptions, boundaries are not often clear.
Our temperature sensors both respond to and induce other perceptions. A warm room filled with daylight may feel less warm because daylight creates a sensory “expectation” that the warmth is natural and appropriate (Ecole Polytechnique Federale de Lausanne, 2019). And when we feel physically cold, we may feel more in need of social “warmth” (Young, 2021).
Drugs, diabetes, shingles, kidney failure, and other conditions can damage those nerves, a condition called peripheral neuropathy, which usually affects the hands and feet. The ability to sense temperature may also decline with age.
Inner sensing (interoception)
Do you have butterflies in your stomach? Are you excited? Or terrified?
Receptors throughout the body send signals to the triangular lobe known as the insula located deep in the brain, the center of interoception, or inner sensing.
This system tells you when you’re hungry and exhausted. It is also essential to understanding your own emotions, which are each a set of body symptoms. For example, when you are angry, your heart rate may increase and your face might feel warm.
About 10 percent of us are especially good at sensing our own heartbeat, a sense called cardiac interoception. This group may also be emotionally intense and better at recognizing other people’s emotions (Critchley et al., 2017).
On the other hand, weaker inner sensing skills tend to go along with a condition called alexithymia, when you can’t name your own emotions (Brewer et al., 2016). Weak or inaccurate inner sensing may be linked to depression and anxiety as well.
Children with autism spectrum disorder (ASD) sometimes are weak in interoception; they might not even notice what would be painful for someone else, or they might need to be reminded to eat. Some can’t tell when they feel full (Day, 2020).
In short, “self-awareness” is physical. For centuries, Buddhism has linked the practice of sitting quietly and observing your breathing to emotional mastery. Recent science has found that training yourself to feel your heart beat can cut symptoms of anxiety and discomfort like stomach pains (Sugawara et al., 2020). Vendors of a variety of biofeedback machines claim these can help people sleep and overcome anxiety.
Fish, migratory birds and some animals can detect magnetic fields, a skill that allows them to navigate huge distances. In 2019, a paper appeared describing how some people showed especially strong electrical brain activity in a chamber surrounded by a small manmade magnetic field (Wang, 2019). Were they especially good navigators? This research didn’t say. When asked, participants reported that they could not discern when or if any magnetic field changes had occurred. But that does not necessarily mean such changes can't influence internal senses, such as the sense of direction.
Space does not permit exploring all 32 senses; suffice to say the evidence for them is strong and learning about them has the salutary effect of expanding your sense of what it means to be human. We are, indeed, amazing, and our appreciation grows the more we understand what we all do every day.
Alloway RG, Alloway TP. THE WORKING MEMORY BENEFITS OF PROPRIOCEPTIVELY DEMANDING TRAINING: A PILOT STUDY (.). Percept Mot Skills. https://pubmed.ncbi.nlm.nih.gov/26029969/ Published June, 2015.
Bermúdez Rey, M. C., Clark, T. K., Wang, W., Leeder, T., Bian, Y., & Merfeld, D. M. Vestibular Perceptual Thresholds Increase above the Age of 40. Frontiers in neurology, 7, 162. https://doi.org/10.3389/fneur.2016.00162 Published October 3, 2016.
Brewer, R., Cook, R., & Bird, G. (2016). Alexithymia: a general deficit of interoception. Royal Society open science, 3(10), 150664. https://doi.org/10.1098/rsos.150664 Published October 12, 2016.
Critchley HD, Garfinkel SN. Interoception and emotion. Current Opinion in Psychology. https://www.sciencedirect.com/science/article/pii/S2352250X17300106. Published April 23, 2017.
Day N. Interoception: What It Is, How It Works, & How to Improve Interoception. Raising An Extraordinary Person. https://hes-extraordinary.com/how-interoception-works. Published October 22, 2020.
Ecole Polytechnique Federale de Lausanne. Daylight levels affect our thermal perception. Phys.org. https://phys.org/news/2019-09-daylight-affect-thermal-perception.html. Published September 23, 2019.
Kiley C. Sensory and Sensory Processing Disorder. Mama OT. http://mamaot.com/sensory-processing-disorder/. Accessed June 14, 2021.
Lopez C, Elzière M. Out-of-body experience in vestibular disorders - A prospective study of 210 patients with dizziness. Cortex; a journal devoted to the study of the nervous system and behavior. https://pubmed.ncbi.nlm.nih.gov/28669509/. Published June 8, 2017.
Sugawara, A., Terasawa, Y., Katsunuma, R., & Sekiguchi, A. Effects of interoceptive training on decision making, anxiety, and somatic symptoms. BioPsychoSocial medicine. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7079488/ Published March 17, 2020.
Wang CX, Hilburn IA, Wu DA, et al. Transduction of the Geomagnetic Field as Evidenced from alpha-Band Activity in the Human Brain. eNeuro. Published April 26, 2019.
Young E. We Have Many More Than Five Senses - Here's How To Make The Most Of Them. Research Digest. https://digest.bps.org.uk/2021/04/01/we-have-many-more-than-five-senses-heres-how-to-make-the-most-of-them/. Published April 1, 2021.