Did you know we have eight senses? Yes, eight! When we think of our ‘senses’, the five we were taught in school- sight, hearing, touch, taste, and smell- are most often the ones which come to mind. The ones that help us perceive and make sense of our external surroundings and help us paint pictures of the world in our minds. But there are 3 other crucial senses which help us understand the world and our own bodies: interoception, proprioception, and the vestibular sense.
These are our internal senses, and they work subconsciously, backstage, helping us navigate our experiences.
Have you ever had that fluttery, nervous feeling in your stomach before speaking in front of a crowd? That’s your interoceptive sense picking up on your anxiety. Or maybe you’ve walked through a dark room and instinctively avoided bumping into furniture? That’s proprioception, your subconscious awareness of where your body is in space. And that steadying feeling when you regain balance after ALMOST slipping? That’s your vestibular sense, making sure you stay upright and coordinated.
These three senses are extraordinary, connecting us not just to our environment but to ourselves. Together, they form the foundation of our everyday experiences, how we perceive and live them. Let’s explore these fascinating senses, the neuroscience behind them, and discover the many ways they play into our everyday lives.
Interoception: The Body’s Internal Voice
What is Interoception?
Interoception helps us sense and perceive the body's internal state by receiving and processing sensory information from the body. It is how our nervous system processes what is going on inside the body.
This sense helps us recognize when we’re hungry, thirsty, stressed, tired or sleepy. It helps our bodies maintain a ‘stable’ sustainable state, known as homeostasis. It also plays a role in feeling and understanding our emotions, by giving us physical signs. (Dunn, Galton, Morgan, 2010). For instance, when we feel a flutter in our stomach when we're excited, or when a sad movie brings that lump to our throat—it's our interoceptive sense giving us a physical experience of the emotions we're feeling!
Interoception helps us tune into the communication between our brain and our body
Think of interoception as your best friend It anticipates your needs and worries, tells you when you’re making a bad decision, accompanies you through all your experiences and helps you feel and sense the happy and the sad moments in life.
How Does Interoception Work?
Interoception relies on sensors in our organs, skin, and muscles that pick up signals given by our body, like changes in our heartbeat, stomach activity, or breathing.
- These signals travel to the brain through a nerve called the vagus nerve - the main nerve of our body responsible for involuntary functions such as heartrate, digestion, and so on - and through other pathways.
Once the brain receives these signals, it processes them in different areas of the brain, like:
- The insula, which helps us become aware of our internal sensations.
- And the anterior cingulate cortex (ACC), which connects these sensations to emotions and decisions.
This is how we connect physical signals to our experiences and emotions. A great example of this, could be how we associate a racing heart and sweaty palms to fear.
Activity Time!
Here is a small activity to test your interoceptive sense!
Interoception-Deep Breathing Test:
Sit quietly, close your eyes, and focus on your breath. Take deep breaths and relax. Notice how your chest and abdomen rise and fall.
Ask yourself: Can you feel your heartbeat without touching your chest? Keep trying!
Proprioception: Knowing Where You Are
What is Proprioception?
Proprioception is our body’s sense of position and the perception of bodily movement. It tells us where our body is in a space. This is important for our everyday movements and it helps us perform activities like walking, picking up objects, or scratching an itch without needing to look. (Tuthill & Azim, 2018)
Do you know of those video games where we can see ourselves from above and, therefore, know where we are and what our surroundings are so that we can move accordingly? That is the proprioceptive sense!
It acts as our body’s subconscious navigation system that tells us where we are in our immediate environment.
How Does Proprioception Work?
Proprioception depends on special sensors called proprioceptors, found in our muscles, tendons, and joints. These sensors detect various movements of our muscles and joints and how much we move them.
There are 3 types of proprioceptors (Tuthill & Azim, 2018):
- Muscle spindles: sense when muscles stretch and help the body know its position.
- Golgi tendon organs: monitor tension in muscles to prevent overexertion.
- Joint receptors: provide information about the movement of our joints and its limits.
These signals are sent to the brain through the spinal cord.
Once they are in the brain:
- The somatosensory cortex helps identify the position and movement of body parts.
- Then, our cerebellum fine-tunes our movements, ensuring they are smooth and coordinated.
For example, when you reach for a cup, the proprioceptors tell your brain exactly where your hand is and how much to extend it to grab the cup properly.
Activity time!
Give this activity a go to engage your proprioceptive sense!
Closed-Eye Arm Test:
Extend one arm straight out to the side. Close your eyes and slowly bring your arm forward to touch your nose.
Did your finger find your nose without needing to open your eyes?
That’s your proprioceptive sense at work!
Vestibular Sense: Staying Balanced
What is the Vestibular Sense?
The vestibular sense helps maintain our balance become aware of our motion, and coordinate the rest of our bodies to accommodate for movement.
It tells us which way is up and down and helps us reposition and reorient ourselves accordingly. It lets us walk upright, keep our balance on uneven ground, and know when our body is tilting or spinning (Beraneck, Mathieu, Elliott, Glover, & Straka, 2023)
Our proprioceptive sense creates an awareness of our body’s position in our surroundings and the vestibular sense moves to perceive and balance our bodies according to our own movements.
Just like how a tightrope walker uses a long pole to balance themselves, or a Weeble toy always reverts to an upright position, our bodies use the vestibular sense in the same way!
How Does the Vestibular Sense Work?
Our vestibular system is located in the inner ear
and includes:
- Semicircular canals, which sense when your head turns or rotates. Inside these semicircular canals, there’s a fluid that moves when your head rotates. This movement bends tiny hair cells, which send signals to your brain about the rotation.
- Otolith organs (the utricle and saccule), which detect up-and-down or side-to-side movements and changes in head position relative to gravity. In the otolith organs, small crystals shift when you move or tilt your head. This kind of bending also activates hair cells that inform your brain about straight-line movement or tilting.
- These signals are sent to the brainstem and cerebellum, where they’re combined with information from your eyes and the rest of your body to form and perceive any imbalance in bodily or head orientation.
- This helps maintain your balance and posture. For example, when you trip, the vestibular system helps you quickly adjust and regain balance.
Most of the input received by the vestibular system are a result of our own actions!
Activity Time!
Try this activity out to getter a better sense of how this sense works!
Walking in a Straight Line:
Close your eyes and try to walk in a straight line for a few steps.
Notice whether your body stays aligned or if you tend to veer off to one side!
Experience how our vestibular sense works even with our eyes closed i.e., without visual input!
A Unified Experience.
These three senses constantly coordinate with each other and the external senses to give us a comprehensive awareness of our lives.
Each one of these 8 senses has some role to play in every interaction we have with the world. Even in memory, when we think about any event or experience, we remember aspects created by each of these senses.
Even if you’re doing something as simple as walking, all of these senses come together to give you small but important components of that experience – your eyes see a couple of butterflies, your ears hear the sounds of birds, your vestibular sense makes sure you are maintaining your balance while looking around, your proprioceptive sense makes sure you don’t bump into anything and even your interoceptive sense makes you aware of how tired your body is through your sweat and breathing patterns!
Conclusion
Interoception, proprioception, and the vestibular sense are the unsung heroes of our sensory systems. They operate in the background such that we do not have to pay conscious attention to these aspects of balance, spatial orientation and whether we need food or not. By understanding these senses, we can better understand and appreciate how our brain and body work together to create a seamless and memorable experience of the world and help us become more in tune with ourselves.
Try spending a day consciously tuning into these internal senses! Whether you’re out and about or spending the day in the comfort of home, see what it is like to spend the day with 8 senses instead of 5. It’s sure to be a unique and interesting experience!
Written by
Sharvari Raste
(Student)
Mu, Y. (2023). Understanding Interoception and Its Importance in Body and Mind Functions: A Review. International Journal of Social Science and Humanity.
Murphy, J. (2024). Interoception: Where do we go from here? Quarterly Journal of Experimental Psychology, 77(2), 223-229.
Garzorz, Isabelle & Deroy, Ophelia. (2020). Why There Is a Vestibular Sense, or How Metacognition Individuates the Senses. Multisensory Research. 34. 1-20. 10.1163/22134808-bja10026
Khalsa, Sahib & Adolphs, Ralph & Cameron, Oliver & Critchley, Hugo & Davenport, Paul & Feinstein, Justin & Feusner, Jamie & Garfinkel, Sarah & Lane, Richard & Mehling, Wolf & Meuret, Alicia & Oppenheimer, Stephen & Petzschner, Frederike & Pollatos, Olga & Rhudy, Jamie & Schramm, Lawrence & Simmons, William & Stein, Murray & Burrows, Kaiping. (2018). Interoception and Mental Health: A Roadmap. Biological Psychiatry: Cognitive Neuroscience and Neuroimaging. 3. 10.1016/j.bpsc.2017.12.004.
Khan, Sarah & Chang, Richard. (2013). Anatomy of the vestibular system: A review. NeuroRehabilitation. 32. 437-43. 10.3233/NRE-130866.
Cullen, K. E., & Zobeiri, O. A. (2021). Proprioception and the predictive sensing of active self-motion. Current opinion in physiology, 20, 29–38. https://doi.org/10.1016/j.cophys.2020.12.001
Tuthill JC, Azim E. Proprioception. Curr Biol. 2018 Mar 5;28(5):R194-R203. doi: 10.1016/j.cub.2018.01.064. PMID: 29510103.
Dunn BD, Galton HC, Morgan R, et al. Listening to your heart. How interoception shapes emotion experience and intuitive decision making. Psychological Science. 2010 Dec;21(12):1835-1844. DOI: 10.1177/0956797610389191. PMID: 21106893.\
Beraneck, Mathieu & Elliott, Karen & Glover, Joel & Straka, Hans. (2023). Editorial: Development of the vestibular system. Frontiers in Neurology. 14. 10.3389/fneur.2023.1191086.