Bummer! our face doesn't show them at all.

Anthony Carboni here for DNews and you can usually tell how someone is feeling by their facial expression.

There's a commonly held theory that across all cultures, humans actually only have six different emotional facial expressions.

Happiness, sadness, fear, anger, surprise, and disgust.

All this is based on some research by a psychologist named Paul Ekman based on a theory by Charles Darwin.

Darwin thought that people worldwide must manifest emotions in the same way,

And Ekman traveled around the world asking people from all types of cultures to show him those emotions.

And the expressions always matched.

He called it the Basic Emotion model, and he said that he could even use it to recognize a liar by the difference between an actual expression and the microexpressions made by someone attempting to mimic them without the actual feeling behind them.

He even consulted with the CIA about it in the 70s to help their interrogators.

The research has been pretty widely accepted since it debuted in 1969, but certain studies have shown otherwise.

One showed people pictures of two scowling faces and said "Hey, do these people feel the same way?"

And the answer was not always yes.

Another showed people an angry face, but didn't give them "angry" as a choice.

Those people were perfectly happy to choose "disgust" or "contempt" instead.

So, it sounds like we might be too complex to fit into a model.

But what if the model is actually too complex for our faces?

New research by the University of Glasgow says that we've actually got four emotions that we universally express.

Happiness and sadness are two of them, but fear and surprise are the same, and anger and disgust are the same.

The study says that all humans begin with the same simple expressions of biologically-rooted signals.

All the other details are added depending on the culture and society we live in.

Smiling is always happy, frowning is always sad, scrunching our nose is the beginning of anger and disgust, though.

And that comes from a basic need to show something displeasing or dangerous is happening, and it also stops us from inhaling harmful particles.

Fear and surprise start the same too, with widening eyes - you take in more visual information, you assess your situation, you look for a potential escape.

After those four basic emotions, everything else is actually cultural.

As we spread out across the world, we created much more nuanced expressions to fit our societies.

Studies show that Asian cultures use the eyes much more to identify emotion, while Europeans use their mouths much more.

I went to Russia last year and people told me that I was smiling too much, and that it looked fake.

I don't know if that's because I'm American or because they see me for the shame that I really am.

You know what else I'm wondering?

I've got a dog at home, and I feel like I could read his expressions, too.

I wonder if they use the same emotions.