Have you noticed your back lately? Yes, that thing between your belly and the chair. Two seconds ago, you were not even paying attention to it. But for sure you now know it is there. Same applies to the soles of your feet or the skin between your fingers. This is not very abstract, after all, you can feel it. However, you were not continuously aware of such sensations before reading these lines. I hope I have facilitated some questions like “are there any other sensation we are missing?” or “are we aware of all that we can feel?” What do you think? Let us know in the poll!
This post is about sensing the world, but don’t worry, this is not a pseudo-scientific mystery magical tour, set to uncover a “sixth sense”, “street smart mode” or “mind reading power”. This is a concrete, scientifically proven, set of senses that many people never consider. Even when recognized, they don’t get into the same category as the more traditional senses. You have been lied to. You’ve been told there are only five senses and these are: smell, taste, touch, sight and hearing. Those are indeed great senses and they get to be called “traditional” but that’s all. I will devote this article to expand the list of senses towards those, often neglected, non-traditional ones.
An easy way to think about sensing is that, somewhere in your brain, there are neurons that can translate from the physical language (e.g, sound or friction) into brain’s language (i.e, neurons communication with each other so you can hear or touch). This often includes a “translator” or sensory organ. Sugar is sweet because you have sweet receptors on your tongue that recognize it and send the signal to the brain. Again, a physical thing such as sugar gets translated into neuron language. I trust your common sense – pun intended – to bear with me as I walk you through some brief examples.
Your sense of balance is one of the most neglected ones. The protagonist of this sense is the vestibular system, located in your inner ear (that’s why super loud sounds can make you lose balance). This sense allows you to walk and do an amazing amount of crazy movements without falling (see above). It also works to stabilize the image projected from your eyes when you move your head. Try focusing on this word “HERE” and tilt your head from side to side. Without your vestibular system, the word “HERE” would also tilt side to side!
Winter time means you avoid going outside, especially without a couple of extra clothing layers. Why? Because you can sense the temperature and low temperature can be dangerous, even deadly. Luckily, our body comes equipped with receptors activated by temperature and a quite impressing temperature management procedure (which is not within the focus of this post). Different types of receptors work in different ranges of temperature. A fun fact is that some of the temperature sensitive receptors can be activated by some substances present in plants; that’s why red chili peppers feel “hot” or menthol gives you a “cool” sensation.
Time perception works at different levels. The strongest evidence of time-keeping in our brain comes from a region called suprachiasmatic nucleus. This region is involved in synchronizing our day-to-day internal clock around the 24 hours it takes the Earth to rotate. Even in complete dark (which scientists call free running), animals have a sleep-activity cycle that revolves around 24 hours and that’s thanks to the suprachiasmatic nucleus.
Pain is a very useful thing that nobody wants to feel. Feeling pain is useful because it prevents us from hurting ourselves and helps avoiding future harmful experiences. Thus, we have a pain-avoiding system turned on 24/7. For example, pain can be sensed in skin via touch and thermal detectors (extreme pressure, stretching, heat, cold…). Although sensed in the skin, pain does not fit within touch or temperature, it is represented separately in the brain as a different sense (yes, you guessed it, the sense of pain).
If yoga lessons taught you anything, it is that you can sense when your muscles are stretched. When any muscle stretches too much, your muscle spindle sends a signal that will make you contract the muscle to protect it from injury. Without the muscle spindle, you’d “pull a muscle” way too often! This type of sensing also works for you to know where is your body in space.
This sense is related to your internal state and is strongly related to survival. Two brief examples can make you realize that it exists. First: You know when you are hungry because you can sense it. Second: You feel suffocated when there’s not enough oxygen for you to breathe.
I don’t want to miss the chance to speak about crazier senses that other animals have. Bats have a sonar-like system, called echolocation, which allows them to move around, hunt and avoid hitting each other in dark caves that have thousands of them flying. Many birds can sense the magnetic field of the Earth (not identical but close enough to a compass). Other animals can see polarized light, out of every corner senses keep appearing! Maybe someday there will be a complete list of human and non-human senses…but who’s counting anyway?
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