Hi there.

I'm Hank Green. And now, I'm … Super Hank Green!

And I have super powers like can't see very well and really like they might be giants. [♩ INTRO ]. According to superhero comics, simply putting on or taking off glasses is enough to completely transform your appearance. Suddenly, mild-mannered Clark Kent is Superman!

And lots of people have claimed that's ridiculous, because a pair of glasses doesn't seem like enough to make someone unrecognizable. But researchers have actually looked into this, because of course they have. And it turns out that thanks to the way our brains process faces, glasses can be enough to keep you from recognizing someone, especially a stranger.

Which, in a world full of photo IDs and eyewitness testimony, is kind of a big deal. Faces are special to us humans because social interaction is key to our survival. They're so special, in fact, that your brain has entire systems dedicated to recognizing them.

Some regions of your brain, like the occipital facial area, respond specifically to parts of the face, like the eyes or nose. Meanwhile, your fusiform gyrus responds to the whole face. It tells your brain what's what, so you know that you're looking at a face and not a piece of toast or whatever.

Other regions, like the superior temporal sulcus, respond to facial cues — emotional expressions, for example, or where the eyes are looking. But even so, a face isn't recognizable until you draw on your memories and experiences to contextualize it. Which is why it can be harder to recognize a person when something changes.

You might not immediately recognize your boss at the grocery store, for example. Or Superman wearing glasses. No, really.

A 2016 study in the UK with 59 subjects found that glasses made it harder to tell if two images were of the same person. If both had glasses, or both didn't have glasses, the participants could correctly tell if they were the same person about 80% of the time. But if one had glasses and the other didn't, they were only able to tell if they were the same person 74% of the time.

While that's not a huge difference, it was still a statistically significant change, and it shows that glasses can affect how easily you identify someone, especially a stranger. In addition to experiments like these, scientists often study how our brains recognize faces by looking at the outliers. Some people score way above normal on facial recognition tests.

They're called super recognizers, and they're really, really good at identifying faces, even when they've been obscured or disguised, like with a hat or a mustache. And I am not one of them. And that might be because they focus more on the nose than other people do.

Researchers think looking near the middle of the face — right around the nose — may help them process the face all at once, rather than piece by piece. And looking at the face as a whole, rather than an assembly of eyes, nose, and mouth, seems to be an important part of actually recognizing who it is, rather than just seeing the face. So if you want to recognize people better, just right at the nose!

There are people who are completely awful at recognizing faces as well. It's not just an excuse that people use at parties, I swear. In severe cases, it's called prosopagnosia, or “face blindness,” and it's surprisingly common — studies suggest about 2% of people might have it to some extent.

It can be caused by an injury or disease, but many cases are congenital: in the immortal words of Lady Gaga, baby they were born that way. People with prosopagnosia tend to be bad at recognizing faces no matter what. In congenital cases, it often seems to come from structural or signaling problems in the fusiform gyrus, the part of the brain that sees faces as a whole.

In other words, they have trouble distinguishing faces as faces. For example, most people can more easily recognize an upright face than an inverted face, but people with prosopagnosia are always bad at it, no matter the orientation. And they spend more time looking at the mouth area than the eyes or nose, which might explain why they can't match the face to memory.

They're not looking at the right areas — and maybe, they're not really seeing the whole face. Most of us are in between these extremes: okay at recognizing faces, especially ones you see all the time, but still not perfect. Which might not seem like a big deal until you think about all of the real world situations where a person's ability to recognize faces can have some pretty serious consequences.

Like all the places we use photo IDs, or in eyewitness testimony. On the other hand, people who are good at recognizing faces could be used to make things more secure. For example, the London Police Force has their own research-confirmed team of super-recognizers who help identify suspects from video footage.

So, part of the solution to these security issues might be to include recognition testing in the hiring process for jobs where facial recognition is important. We could also eventually let computers, which are constantly getting better at this, take over. Because sure, our brains have special areas for processing faces, but we're not as great at recognizing them as you might think.

And ultimately, that's why Superman's disguise might actually be enough— despite all the flak it's received. As long as he can also hide all the bulging muscles, which I don't know how he manages that. Thanks for watching this episode of SciShow Psych!

If you're interested in learning more about the weird quirks of facial recognition, you might like our episode on how staring at your own face too long can make you turn you into. Bloody Mary. [♩OUTRO ].