Many of us dread seeing ourselves in photos. We go out of our way to appear in the background of pictures, never wanting to be the central focus. Even pictures where we look pretty good make us cringe.

It turns out there’s a scientific reason many of feel that way. And it has little to do with just being vain, it actually has to do with perception and how it can sometimes be skewed. You won’t believe it, but you have no idea how your face really looks.

The issue stems from the fact that we can’t see ourselves as the world sees us. Obviously, if we want to see what we look like, we have to look in a mirror. Because we only see that image of ourselves, we assume that’s what everyone else sees. Since we see that face every day, we think that’s how it actually looks.

It turns out, that’s actually not the case. The mirror reflection is not necessarily what the world sees. That’s because a mirror reflects a mirror image, which is a distorted reality. But because this distorted reality is all we can see, it becomes familiar and real to us.

This mirror image is an inverse image of ourselves. The same reason the writing on your shirt is backwards is the reason your face appears different in the mirror than it does in reality. We can see that the shirt is not an accurate reflection, but we it’s no apparent in our faces.

When we see ourselves in pictures, it’s different than what we have seen in the mirror because it’s not an inverse image. This creates an incongruity that causes displeasure. That displeasure comes a psychological concept called the “mere-exposure effect.”

This effect, also called the “familiarity effect” says that we are more comfortable with things that are familiar to us than those unfamiliar to us. This can include words, paintings, sounds, and more. In this case, it’s our familiarity with the face that we see in the mirror that causes us discomfort when we see it in pictures.

This concept explains why many of us like the way we look in selfies but not in regular pictures. When we snap a selfie, we use the front-facing camera on our phones that creates a mirror image of our face. Since it more closely aligns to what we see in the mirror, we’re more inclined to like those particular photos.

It’s strange to think about, but this means that we have no actual idea what we look like other than through photographs. It seems fundamental to our being that we should know precisely how we appear, but it turns out we only have a distorted image of our own face. It makes us wonder what else we perceive completely incorrectly.

It also means that the face that you can’t stand looking at is what people see every time they look at you. What you think is ugly is how you really look. Maybe you should be nicer to yourself when you’re photographed!