The 5 Weirdest Sixth Senses Humans Have (Without Knowing It)

Or maybe we could just sniff the suspects and see which one seems the most nervous. Yeah, your nose can do that, too -- researchers did another study where they strapped a bunch of gauze pads to participants' armpits to collect their sweat while they watched horror movies. Then they taped the fear-sweat-soaked gauze under the noses of a second set of participants. Those subjects were then shown pictures of faces with completely blank expressions, and scientists found that people exposed to the "fear" sweat were more likely to guess that the expressionless faces were fearful.

Another study was done where they collected the sweat from treadmill runners and compared it with the sweat from skydivers. The skydiver sweat, presumably loaded with terror essence, was shown to light up areas of the brain associated with fear, while the runners' sweat simply smelled awful. At this point we assume that everyone went home and showered for three hours.

Here's a challenge for you: Try to imagine a new color. One that you've never seen before. Just straight invent one. Can't do it, right? You probably figure it's because you've already seen all the colors that are possible. Well, prepare to have your mind blown -- there are lots of new colors out there, we just don't ordinarily have the ability to see them, so describing them to you would be like trying to describe sight to a blind person. And we say you can't ordinarily see them, because science has figured out a way.

In their incessant quest to break reality in ever more interesting ways, scientists successfully managed to show some people a "bluish yellow" color. We don't mean green. We can't really show you what we mean, because the way our eyes work is that when we see blue, the parts of the eye that detect yellow switch off, and vice versa. So it's not supposed to be possible to see a true mix of blue and yellow. Green is something else, the closest thing your brain can offer when you show it something that gets it all confused.

But scientists discovered that we can sense these and other colors that don't show up in the rainbow by fooling our eyes with certain composite patterns. For instance, when you see an image like this ...

... and cross your eyes like it's a Magic Eye puzzle, some people can see an entirely new color that is neither blue, nor yellow, nor green. Then again, some people just see a gradient blob of yellow and blue and assume they're the victims of some prank.

If you think we're just messing with you, there's an example of one such impossible color that most people can perceive without playing complicated tricks on their brain. We call it pink. Pink is an unholy mixture of red and violet that doesn't appear on the rainbow any more than bluish yellow does. Seeing pink is basically the color equivalent of seeing ghosts.

And then, most amazingly, there are the very rare people who are born with the ability to see this world of new colors that the rest of us can't even imagine. These people are called tetrachromats, because they have four cones in their eyes instead of three like the rest of us. Each cone is responsible for seeing about 100 shades, so for us normal folk, that's about a million colors. But for tetrachromats? They see a hundred million colors. We should be thankful that it's rare, since it would make art class harder than AP history.

Every month, women have to go through a range of emotional ups and downs due to the maintenance cycle of their portable baby factories. But it turns out that the menstruation cycle has an added function -- it switches on a superhuman ability to sense snakes. And gay dudes.

As much as we would love to end the entry right there, we realize that it probably needs some explanation. In one study, researchers showed a bunch of women pictures of snakes hiding in a garden, both in color and black and white, in what was basically a terrifying Where's Waldo? What they found was that those women who were in the most fertile period of the month were also the quickest at spotting the hidden snakes.

It probably doesn't have anything to do with fertile women being able to detect the most phallic animals. The theory is that evolution has given women who are ready to reproduce an added cognitive boost when it comes to detecting danger.

But that's not the most interesting thing they discovered -- in another study, when they showed women pictures of men's faces, the women who were on their period had incredible gaydar. And this isn't dumb coincidence -- a woman's ability to pick the gay guy out of a lineup peaked at her most fertile point, and then gradually receded until her next time of the month, and it didn't work at all for detecting lesbians.

Remember, they weren't being shown footage of these guys in line for a Celine Dion concert. Women were able to pick who was gay simply from looking dudes in the eyes. Supposedly, evolution figured that gaydar would be a really handy thing to have when you're a woman looking to start a family, just so you don't waste time with a dude who is going to leave you for your brother.

This is, of course, an ability limited to women. But the guys don't have to miss out, because ...

Researchers wanted to find out whether men could detect when women were more fertile, as previously the only known way to figure this out was if the women stripped their clothes off and jumped on a guy's junk. It turns out that not only can men sense when women are ovulating, but they subconsciously change their behavior on the fly to adapt to it.

It's not as creepy as it sounds. When a woman is ovulating, she has very subtle changes in voice, scent and skin tone, all of which men pick up without even realizing it. To explore this, they paired 123 male participants with five women over different stages of their menstrual cycle. Each man had a one-on-one session with the woman (not in the way you think). They were prompted with a picture depicting a certain scenario, like a child giving another a toy, and the woman was asked to describe the situation.

The men were then asked to do the same thing. But what they found was that, when the women were less fertile, the men were more likely to be lazy and just copy what the woman said. But when the women were ovulating and thus more fertile, the men tended to shake it up a little and put more effort into their part. In other words, they were trying harder to impress them. Because they could smell their ovulation.

OK, so it actually is as creepy as it sounds.

We're not talking about the way the blind superhero Daredevil can "see" with sound. This is something different, and weirder.

In one study, they put an old blind man in a maze and told him to find his way out on his own, hopefully after the man volunteered for it. And what happened? He completed the maze flawlessly. He could "see" the walls and twists and turns, because his retina had figured out how to bypass the broken visual cortex and send the information to the brain. He was still blind, but his eyes and brain had found a workaround. He was not, however, able to escape from the tiger the scientists had released into the maze.

In another study, researchers put pictures of happy and sad people in front of blind people. And again, they found that the blind people were able to tell most of the time which faces were sad and which were happy. They couldn't see the faces, but their brains knew what was in front of them.

How? Well, for many blind people, there's really nothing wrong with their eyes. The problem is usually with the visual cortex, the part of the brain that processes what the eyes see. It's just like taking the film out of a camera and replacing it with spaghetti -- the camera works fine, but it's still useless to you. But what if somehow your body could find another way to send the information from the retina to the brain? It happens, and it's called blindsight. Some blind people develop it and are able to have complete awareness of their surroundings, even if they believe that they don't. It doesn't mean that you can throw away your blind uncle's cane, but you probably shouldn't walk around in front of him without pants anymore.

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For other ways you're more like an X-Man than you think, check out 5 Superpowers You Didn't Know Your Body Was Hiding From You. Or discover the 5 Superpowers We All Had as Babies (According to Science).

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And to further expand your noggin, check out Cracked's De-Textbook: The Stuff You Didn't Know About the Stuff You Thought You Knew.