It turns out that not everything we were taught was true.

For example, we were taught since childhood, that we only have five senses. But probe a little deeper and there are far more.

Scientists have discussed that we have more than the 5 basic senses we knew since kindergarten. Yes, you read it right.

Of course, you’re familiar with the big five: vision, hearing, smell, touch, and taste. The idea of five classical senses dates back at least to Aristotle.

However, Aristotle argues that there can be no sixth sense because there are only five sense organs. And, that’s where he got it wrong.

But how many senses do we really have?

According to LiveScience, we have more subtle senses that most people never really perceive. Here are the additional senses that scientists have found:

1. Proprioception

This refers to how your brain understands where your body is in space. It is our innate ability to tell where our appendages, muscles, and other body parts are in space.

Try to put your finger on your nose in darkness. That’s the sense of space or proprioception.

According to this article, this is an interoceptive sense that indicates whether the body is moving with required effort. In layman’s terms, it is what tells us where the various parts of our body are located in relation to each other.

This is also called the “position-movement” sensation by Julius Caesar Scaliger in 1557. But it was Charles Bell in 1826 who expounded the theory of muscle sense.

Bell proposed that commands were being carried from the brain to the muscles, which lets us know where and what our body is doing even with our eyes closed.

The basis of proprioceptive sense is believed to be composed of information from sensory neurons located in the inner ear and in the stretch receptors located in the muscles and the ligaments.

Research published in The New England Journal of Medicine states that there are people who have an impairment with this sense. It could be caused by adolescence or a certain mutation in gene PIEZO2.

For the latter, it results in weaker than normal mechanosensation. Subjects with this mutation received weaker neuronal signals from their senses to their brains. In turn, they tended to be clumsy and less coordinated.

However, proprioception sense can be sharpened. One method is the Alexander Technique to enhance the kinesthetic judgment of effort and location. Another exercise is Yoga to challenge body positioning.

The Tai Chi discipline also enhances and provide a good environment for proprioceptive information so that the mind and body integration will be developed.

2. Equilibrioception

This refers to our sense of balance. This ability is regulated by the fluid in our inner ear while working with our sense of vision to navigate us around safely.

A good example is when we try to spin fast over and over again, we can throw off our equilibrioception. This leads to dizziness and inevitably a loss of balance.

Needless to say, our sense of balance is what enables us to walk without falling. However, this sense degrades as we grow older, which is the cause why elderly people are prone to falls.

Equilibrioception is closely inter-linked with proprioception because it also takes its input from various receptors in the body including the visual system (the eyes), the vestibular system (the sensory system in the inner ear) and the proprioceptors.

In equilibrioception, the visual system is important. It is because it is through our vision that our mind knows which way is up.

When the body is accidentally tilted or in a state of imbalance, the head will suddenly move to level the eyes with the horizon. When our sense of balance is rocked, it will lead to disorientation.

In our example above, when we try to stay still after spinning, it rocks out the vestibular system because of the “moving” sensation that we feel. But our vision system tells our mind we are “still” since we are staying in one place.

The disagreement between these two systems creates disorientation for the brain and leads to nausea and vertigo. Sounds familiar? That’s also what happens when you’re drunk. So stay sober to retain your equilibrioception sense.

3. Thermoception

It refers to the sense of heat, as well as the sense of coldness. In short, this is the sense that tells us if we’re on fire or if winter has begun!

This is different from our sense of touch because thermoception senses temperature while our sense of touch is sensitive to pressure on the skin.

Just like the cat is the perfect example for equilibrioception, the rattlesnake is great for thermoception. They can sense the warmth of their prey (thermoception) even without touching them yet.

For us, humans, our thermoception sense is less developed compared to bats and certain snakes. But, this sense is functioning in our body by telling us when to put on our gloves or when to turn on the AC.

Our skin has sensory receptors that detect the temperature and they are of 2 types – warm and cold receptors. Warm receptors send signals to the brain during an increase in temperature, and cold receptors fire signals when it is cold.

When the temperature is over 45 degrees Celsius and less than 5 degrees Celsius, our pain receptors send signals to the brain. That is why we feel pain when we touch a boiling pot.

Thermoception is the sense that saves us from extreme heat and cold and helps regulate our body temperature.

4. Chronoception

This refers to our sense and perception of time, which is usually difficult to talk about. The reason is that scientists are still figuring out if chronoception is a neurological sense – along with the lines of sensing temperature and balance – or something more psychological.

Do you get stressed if you have a fixed period of time ahead of you? For example, if thinking about the ‘2 hours’ you have before you go to the office or the 8-hour deadline your boss gave you is stressing you out, then you have a “poor” sense of time.

Professor Warren Meck has found the representation of time to be generated by the oscillatory activity of cells in the upper cortex of the brain.

According to ScientificAmerican, we can sense the passing of time. Neuroscientists believe that we have distinct neural systems for processing different types of time – like maintaining our circadian rhythm.

In fact, a new study, reveals that the brain may, in fact, have a second method for sensing elapsed time. What’s more interesting is that neuroscientists are proposing that our “second internal clock” not only works in parallel with our primary body clock but may even compete with it.

If you think these four senses are interesting, there are some even more fascinating senses found outside of the human species. Take for example magnetoreception or the ability to sense magnetic fields that bats use to navigate and electroception or the ability to detect electric fields that sharks use to detect their preys.

And with the advancement of science and technology, it is not surprising that neuroscientists are finding more and more information about how our mind and body works. Let’s just wait and see for more developments and for these findings to be published in “mainstream” books for our children’s children to learn about it in the future.

 

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