One of my favourite things to do is to sit at a cafe (best if it's a corner seat) and people watch. It's astounding what one can learn simply from a person's body language and facial expressions.

When it comes to facial expressions, we like to think that we humans win top prize for most number of expressions created. Most of the time, my cat has only two expressions - bored and annoyed. And when it comes to facial expressions, we like to think that we are pretty good at reading what other people are thinking or how they are feeling purely based on expression too.

 If you happen to have Resting Bitch Face, good luck. 

If you happen to have Resting Bitch Face, good luck. 

Make a wild guess. How many facial expressions do you think humans are capable of? If you start counting, you’ll probably come up with some like happiness, sadness, anger, disgust, fear, surprise, confusion, hunger, boredom, and impatience.

According to psychology professor Dr. Paul Ekman, there are only six facial expressions which are considered distinct expressions. They are anger, fear, surprise, happiness, contempt, and disgust.

Six doesn’t seem like very much at all! But the University of Glasgow took this even further by challenging Dr. Ekman's theory with the idea that humans are actually only capable of four facial expressions. They suggest that disgust and anger should be counted as one expression, as well as fear and surprise.

 Guess this movie should be labelled under the 'Documentary' genre?

Guess this movie should be labelled under the 'Documentary' genre?

Our facial expressions don't happen all at once, obviously, so how researchers came to the conclusion of four expressions is by a time-lapse examination of how how, when, and which facial muscles were activated for each different expression. They found that disgust and anger, as well as fear and surprise, started out the same way.

Disgust and anger both started with one key element -- a wrinkled nose, that then evolved to differentiate one expression from the other. Fear and surprise both started with both eyes widening.

All this happens in milliseconds. But when it comes to human survival, a split second can often make all the difference between life and death. Early humans have long relied on their reflexes to keep alive, and at the core, I guess that's what facial expressions are all about. Giving them that split second longer to survive.

This can also be applied in our current daily lives. Knowing what to look for may give you an added advantage when it comes to telling whether someone’s lying, picking up on a fake smile, as well as diagnosing potential mental health issues.

While it might seem as though people are capable of a wide range of facial expressions, now we know we only really have four: happiness, sadness, fear/surprise, and disgust/anger.