1. It takes time for your brain to process signals, so everything you perceive as happening in the present is actually a snapshot of the past.
It takes somewhere on the order of 100 milliseconds for your brain to process a sensory signal. That means that by the time your brain decides where something is at a given moment, the object is actually somewhere else in the “real world.” Scientists are still not clear on how brains compensate for such a delay.
2. This delay has been proposed as an explanation for the famous flash-lag optical illusion:
3. In fact, our brains receive different visual cues, as well as signals from different senses, at different speeds.
Our brains may be constantly correcting and compiling everything together once all those signals reach “the finish line.”
4. When terrifying things seem to happen in slow motion, you experience the event at the same speedas any other event in the moment. It’s the memory of it that’s different.
This has actually been tested by dropping people from high above into safety nets while recording their perception of time! The researchers suggested that the perception of the memory is slower because your brain recorded the terrifying event in more detail.
5. If you regain sight after being blind most of your life, your eyes may work, but your brain will likely have no idea what to do with the new information.
There aren’t that many cases of people who lost vision in infancy (or before birth) regaining vision. But of the few who have experienced it, many have had trouble getting their brains to figure out how to interpret visual imagery. As an example, a person may have trouble with depth perception and see people walking away as literally shrinking in size.
6. If you put glasses on that flip your field of vision and wear them for a while, your brain will eventually flip the image such that when you take them off, the real world will be flipped.
This was first famously demonstrated by psychologist George Stratton. It took five days of wearing the glasses before his eyes adapted. After some time, his eyes returned to normal.
7. There’s actually a rare genetic mutation that allows some women to see 100 times more colors than an average person.
The condition, called tetrachromacy, comes from having four cones (receptors in your eye that interpret color) as opposed to the usual three that most humans have. One noted artist/tetrachromat described the experience of looking at a basic pebble walkway to the BBC. “The little stones jump out at me with oranges, yellows, greens, blues and pinks,” she said, adding, “I’m kind of shocked when I realise what other people aren’t seeing.”
8. Humans only see a fraction of the wavelengths of light that some other animals can see.
Humans can see in the “visible spectrum” of light — named so because it is visible to humans. But bees, for example, can see ultraviolet light (wavelengths shorter than those in the visible spectrum) but not red. Snakes, in some cases, can see infrared light (longer waves than our visible spectrum, aka heat).
9. And even then, there are a ton of other wavelengths out there no one sees! Here’s the spiral galaxy Messier 106 in visible light (left) and with X-ray and radio waves added (right):
Look at that! Two more spiral arms!
10. Forget vision! There are also a ton of tone frequencies out there that humans aren’t hearing.
11. When you taste spiciness, your brain is actually being tricked by a chemical that activates parts of your tongue meant to sense temperature.
The chemical is called capsaicin, and it’s found in spicy peppers.
12. It’s not only spicy foods that trick you. There’s something nicknamed “the miracle fruit” that makes sour things like lemon and lime taste super sweet after you eat them.
The effect is due to the aptly named chemical miraculin. Miraculin itself doesn’t taste sweet, but it binds with and modifies sweet receptors to be activated in the presence of acidic things like citrus.
13. If you are anxious or scared, you likely have a heightened sense of smell.
It was a small sample size, but a group of researchers found that the more anxious a group of subjects were, the better they were at discriminating negative odors accurately.
14. Holding something warm will make you perceive others as “warmer” from an emotional standpoint.
Other physical things affect your perception of emotions too. A collection of studies found that people holding heavy clipboards were more likely to, among other things, rank issues related to fairness as more important than people holding lighter clipboards.