If I were to ask you, “What do you know about yourself?” You would probably raise an eyebrow at me for asking such a ridiculous question. Most of you would say you know quite a bit about yourself, since you have been present in this world for a good few years. You think you know who you are, where you are from, what you’ve done, and so forth. And I would agree, you do know yourself… in that context.
The concept of sense perception comes from the idea of numerous unique perspectives on the same exact thing. It’s something we learn when we are young, sitting on the floor in Grade One, learning about the fuive basic senses: sight, smell, hearing, taste and touch. As we grow older, we learn about a “sixth sense” to perceive what may not be there. (Heavily influenced by the actual movie, The Sixth Sense, but go along with me here). Biologically, all your senses work because of the nervous system you have, with nerve endings travelling along sensory neurons to your brain, where most of your senses are received and interpreted. So as long as we tinker around with the nerves within your body, we can do some pretty wacky things…
1. Sight
We see because of rods and cones within our body, located at the back of our eye, on the retina. When receiving light, these rods and cones fire signals to our ganglion cells, which send a signal to the occipital lobe in our brain. Seems pretty flawless right? Well, when the signal is interpreted differently by the brain, some odd things begin to pop up…
Here, both tables seem drastically different in size, but are in reality the exact same. Take a ruler and measure it out yourself and you’ll find them both to be the same length and width, at the same angles as well. Sure enough, your brain can’t wrap it’s head around it, and gives up altogether.
Want another? Our brain is very clever at taking and filling in gaps of incomplete data to make everything work out (almost like the brain has OCD), but sometimes struggles to put the pieces into place with an impossible image. Take the elephant for example, where are the legs?
2. Smell
Do you think you could tell the difference in scent of an orange and lemon? What about a lemon and lime? This is an effect being currently investigated as the olfactory illusion, where humans smell the same scent differently. Want to try for yourself? Have you and a couple friends blindfold yourselves, and then try smelling various scents. Who can get all of them correct? Tough to say, but you won’t get the same answers between everyone. Scientifically, there is no evidence that an olfactory illusion exists, but scientists do believe, that between humans and humans, or humans and other animals, we all perceive scents differently.
3. Touch
On our skin, we possess numerous receptors of hot, cold, light, and heavy touch, all of which have unique neurons to send to our brain. However, as sensitive as these receptors are, they are not the best at perceiving touch when OUTSIDE of their normal orientation. This is called the Aristotle illusion. Cross your fingers together as if you were going to break some promises, and then touch a round object like a pea with both fingers, and you’ll feel like you’re touching two distinctly different peas. Cool huh?
4. Taste
Your palette is your range of tastes that the chemoreceptors on your tongue possess. They are often a range of tastes and flavors, consisting from sweet, salty, bitter and sour. However, they are not perfect. Not even close.
In the Butcher’s Tongue illusion, people stuck their tongues into a box and viewed what they thought to be their tongues in a mirror. In reality, it was a rubber double that they were viewing. When the scientists stroked the fake tongue with a Q-tip, over 40 per cent of the test subjects felt the Q-Tip on their own tongue, even when it wasn’t true at all. This test went even further, when scientists showed the patients a Q-tip being dipped in lemon, and then placed onto the fake tongue. At the same time, a Q-tip dipped in plain water was placed onto the actual tongue of the test subject. You can guess what the result was.
5. Sound
And last, but not least, my personal FAVORITE illusion ever, it is my pleasure to introduce, the McGurk effect.
If you have never seen or heard of the McGurk effect, it is a trick played on the ears where there is an interaction between the visual and audio version of perceptions. It works from the combination of auditory stimulus and visual stimulus, leading to the perception of a third sound. A conflict in visual perception and auditory perception leads to a change in the auditory perception, so some really WEIRD things happen.
In the McGurk effect, people hear the noise “ba, ba, ba”, however, once revealed to an image of a person saying “fa, fa, fa” they also hear the noise “fa, fa, fa”, however, the noise of “ba, ba, ba” never changed. The best part about this illusion is the fact that no matter how hard you try, you will never stop hearing “fa, fa, fa” once you see the photo, even if you know it is saying “ba, ba, ba”. Tricky ears they are, tricky ears…
6. BONUS! Proprioception
You need a partner for this mind-boggling trick, preferably someone who can lift you easily. Lie on the floor, have your chin tucked deeply into your chest, and stay there. Stretch your arms out, and relax. On “go,” have your friend lift up your arms higher and higher, (without lifting you entirely off the floor) while still having your chin tucked in. After 60 seconds, have your friend slowly drop your arms slowly down, making sure that the head touches the floor first. Once you do so, you will feel the most impossible sensation ever: your arms will fall below the floor.
So, the next time someone asks you how well you know yourself, you now know your answer: “Well, I do. But I don’t. But I do? You know what, I really don’t know. I don’t think I know anything any more.” You can thank me later.
