Participants in the Queensland University of Technology study mostly described the left object as happy and feminine, while the image on the right was described as more angry and masculine. Photo: Supplied
A smiling muffin a man in the moon even Jesus Christ on a piece of toast, why do we humans tend to see faces in inanimate objects?
New research out of Australia sheds light on the phenomena known as pareidolia.
According to the Queensland University of Technology study, people detect happy faces faster, and people are more likely to rate 'feminine' faces as happy - even when those faces are not human.
We are pre-wired to see faces everywhere, study author Professor Ottmar Lipp from the Queensland University of Technology told RNZ's Nights.
"What we are biased to do as humans is to see faces everywhere, on the rock face, in a tree, because faces are inherently important stimuli for us."
It's an important biological trait for humans to recognise faces, he said.
"They are a very good, very rich source of information about other people. So, by simply looking at a face, I can get a fair idea how old the person is, whether they're male, female, whether they are of the same ethnic group, or different ethnic group."
Happy pastries and grumpy cars: Exploring face pareidolia
But why do we see faces in inanimate objects, is this a recent thing? No said Lipp.
"Our bias to see faces everywhere, is something that has been around for a very long time.
"And for all intents and purposes, you could argue it's an expression of how important faces are for us, because we pay attention to things that are important. And that can shift depending on what is important to you. But certain things stay important to you, for your entire life. And other people's faces are certainly in that category," he said.
And we are more likely to see happy faces, he said.
"Amongst the different emotions that we express, happiness is the best recognised, the most reliably recognised. Better than anger or perhaps more threatening expressions.
"And it's the most frequently encountered expression as well. If you go out and look at other people, then most of them will have a smile on their face, they will express happiness, they will express signals of affiliation."
And there is a reason for our tendency to see happiness more strongly, he said.
"It signals something to me that this person is approachable, as opposed to an angry expression or a fearful expression where we have to be a little bit more careful and perhaps try to gauge what that person is about.
"So by looking at faces and looking at the facial expressions, what we can gain is information about a person's intentions if you like."
For the study they showed people a "motley collection" of different objects, Lipp said.
"Handbags, trousers, pieces of cake, cars, typewriters, you name it, you can see faces everywhere .… what we were looking for is whether you could see a face in that object. And sometimes it doesn't even take an object.
"So, one of the pictures we used is an image of three birds flying in the sky. And what they express if if you take them together, you have two eyes and a mouth, and the mouth is smiling. So, it's a happy face that you see."
We strive to see meaningful entities everywhere, he said.
"And one of the most meaningful entities we can see is the face of another human being."