#2. Your Brain Changes the Size of Objects Around You
Your eyes are lying to you right now about something as basic as the size of the stuff you're looking at. Don't believe us? Take a look at the photograph below, and tell us which of the two vertical red lines is longer in your monitor:
Mighty Optical Illusions
Spoiler: You're about to feel dumb.
If you answered the one on the right, congratulations, you're completely normal, and also completely wrong. Check out the same two lines side by side:
They're the exact same size. But why would your brain trick you into thinking that one line is bigger than the other? What have you done to deserve such a betrayal? Well, your brain is actually just looking out for you -- this happens for the same reason that you don't suddenly think that a person walking away from you has turned into a dwarf. It's all about how the brain deals with perspective.
The above photograph is an example of the Ponzo illusion, which occurs when an image's context tricks your brain into seeing size differences. Since the line on the left is supposed to be in the foreground and the line on the right is in the background, your brain insists that the line on the left must be shorter. Here's another one called the Muller-Lyer illusion -- in this case, the line on the left is actually a little bit shorter, and still looks longer.
Point all you want, kid, it'll always be shorter.
So where have you seen this type of illusion in real life? Just look at the sky at night. When the moon first pops up over the horizon, it looks enormous, but it gradually shrinks over the next few hours, until it's just a pathetic old thing hanging in the middle of the sky by midnight. That doesn't mean the moon has suddenly moved farther away from the Earth -- it only looks bigger on the horizon because objects in front of it, such as trees and buildings, create a perspective illusion.
If you see four at the same time, though, you probably need new glasses.
But here's the weirdest part: Because these illusions are based on context, how badly they fool you depends on what you're used to seeing ... meaning that city dwellers are more vulnerable to being tricked. On the other hand, if you grew up far from civilization, your brain won't contain as many images of large, man-made rectangular objects, so it won't be as easily fooled by these illusions. Then again, in this case, you may just as likely believe that the moon is some godlike being that lives in the sky, so maybe that's not much better.
#1. You Can Easily Forget Where Your Limbs Are
If someone put a fake rubber hand next to your real hand and asked you which is which, it'd probably take you less than a second to answer that question by flipping the guy off. After all, what kind of moron would confuse their own hand with one made of rubber?
The answer is: you. You're that moron. Because of the way our brains work, it's easier than you think to trick ourselves into "misplacing" body parts, as demonstrated by the Rubber Hand Trick (which, shockingly, isn't a sex maneuver). Check it out:
Basically, the woman in the video is shown a clearly fake rubber hand next to her real one, which is hidden from view. When both hands are touched at the same time, the woman ends up thinking the fake appendage is her own, since that's the only one she can see. Yep, it's that simple. In fact, if someone hit the fake hand with a hammer, the woman would flinch, like the one in this other video.
The freakiest part is that once your brain adopts the rubber hand as its own, it "forgets" about the real one -- your real hand's temperature will drop noticeably, indicating that blood flow is being restricted. In other words, your brain starts to deny the very existence of your real hand on an actual, physiological level.
On the plus side, rubber hands keep fresh much better.
This illusion shows how your eyes play a huge role in your awareness of your own body parts, which is called proprioception. Proprioception is what allows you to do things like driving without looking at your feet, or typing without seeing your hands on the keyboard. There are a number of illusions that allow you to play around with proprioception, but the most common one is called "drinking lots of booze" -- when you get drunk, your brain gets so screwed up that it momentarily forgets where your nose is. That's how field sobriety tests work, by the way.
"Good luck with whatever you're trying to do, rest of me." -Your Brain
This is also why teenagers are so great at bumping into things -- they aren't used to their newly grown bodies, so they misinterpret the visual cues and end up walking into a table. It's not all bad, though: This phenomenon can also be used to treat phantom limb pain in amputees by simply using a mirror to trick them into thinking that their missing limb is still there. Their conscious mind won't be fooled by such a transparent ruse, but once again the brain will completely eat that shit up.
For more reasons you can't trust even yourself, check out 5 Horrific Ways Your Brain Can Turn On You Without Warning and 5 Ways Your Brain Is Messing With Your Head.
If you're pressed for time and just looking for a quick fix, then check out 4 Insane Details From The Weirdest Murder Trial Ever.
And stop by LinkSTORM to learn the best way to spoon your brain from your head.
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Related Reading: No one enjoys being betrayed by their own brain. Regain some faith in your squishy gray partner and learn about your hidden ability to smell emotions. Then click here to discover all the amazing ways your sense of smell controls your mind. Still have some faith in your powers of perception? This article will blast that misconception away and show you how something as minor as background noise can influence your sense of taste.