The sex appeal of symmetry
We're often told that facial symmetry is what makes us attractive, but why is it that symmetry has such an appeal to us? Do we seem to seek it out even if it's not there? And if so, could it mean our assumptions and theories in physics are wrong? Graihagh Jackson spoke to Ben Jones from the University Glasgow, who explained just how he's investigated our attraction to symmetry...
Ben - There's really kind of two different types of studies that people have done to look at the relationship between symmetry and facial attractiveness.
There are studies where people have measured symmetry in faces and had those faces rated for attractiveness. In those kinds of studies, you tend to see a positive correlation.So, more symmetric faces tend to be more attractive. But it's really quite a kind of weak relationship.
But when you take a photograph of a person's face and then, using computer graphic techniques, manipulate it to be more symmetric, then you start to see slightly larger effects in symmetry, so making a face more symmetric tends to make it look more attractive. If you take an individual face and then kind of exaggerate the naturally occurring asymmetries in it, it very quickly becomes unattractive and even can become really quite sort of bizarre and freakish-looking.
Graihagh - Bizarre and freakish-looking? I had a barbecue last night and decided to conduct my own analysis by showing my friends three pictures of one girl. In one, the image had been manipulated to look extremely asymmetrical. We call this number one. Picture number two is what what we might consider a normal face - a few asymmetries here and there and number three was completely symmetrical. They of course, had no idea why I was showing them three pictures of the same person and it caused considerable debate when I asked them which one was the most attractive.
Female - They're the same. They're just slightly different.
Male - They've got a different crinkle in them because of the paper.
Graihagh - No, that was just my bad folding in my backpack.
Female - They have like, re spaced the eyes haven't they. I can't tell.
Male - I'd say middle.
Female - Yeah, I'd say middle.
Graihagh - You say middle is most attractive?
Female - The more I look at it, 3 is becoming more attractive.
Female - I think 3 is more attractive.
Graihagh - Three is more attractive?
Female - Her eye's wonky on the side. There's a bigger space.
Male - One is nowhere near it.
Graihagh - So, one is the least attractive. We're agreed on this and there's more leaning towards 3?
Female - I think 3 looks like she's got bags.
Male - I'd like to say 3 is the least attractive.
Female - Yeah, I'm going with 1.
Female - The more I look at it, the more I go to this one.
Graihagh - How many for number one?
Male - I don't like the mouth on this one it's a bit frowned down.
Male - I'm going for number one.
Graihagh - So, you're for number one?
Male - Yeah, I've got to now. I've got to say one. Yeah, I'll go with one.
Graihagh - Who is for number two? So, we've got three for number two. You're going to go for number three. You've completely disproved all the science.
Female - What's the science?
Graihagh - So, the idea is, are we bias to seeing symmetry because we find symmetry more attractive? This is the most symmetrical one.
Female - So, I've got the perfect face.
Graihagh - This is extremely asymmetric.
Male - I've drunk a lot of alcohol today.
Female - My eyes are wonky anyway.
Graihagh - I think maybe, we can rule this down to the fact that I've creased the paper too much in my backpack.
Female - Yeah, it's a shame it goes right through her face.
Female - Yeah, and we're doing it in the dark.
Graihagh - Okay, so I'm not entirely sure what we can conclude from that extremely scientific investigation. But overall, my friends did seem to think that the asymmetrical face was the least attractive, but why is symmetry so sexy.Ben Jones again.
Ben - Well, it's kind of quite a controversial issue and there's a number of different theories that have been put forward. If you speak to cognitive psychologists, they'll tend to point to the fact that we kind of develop an internal prototype of faces based on all of the faces that we encounter. But that internal prototype which you can kind of think of as a mathematical average of all the faces that you encounter is likely to be perfectly symmetric because all of those individual asymmetries in the individual faces that we see will kind of average out. We know that faces that more closely resemble this prototype are easier to process and we might even like them more because they're easier to process. And it's that kind of processing bias that could contribute to the appeal of symmetric faces.
On the other hand, working from ideas about animal behaviour and particularly studies of meat preferences in non-human animals, other researchers have theorised that our attraction to symmetric individuals might be less to do with kind of processing biases and more to do with the type of qualities that symmetry might advertise about people. So, one idea is that more symmetric individuals might be healthier, they might be physically fitter, they might be physically stronger. And those are kind of characteristics that we find desirable in potential mates, and also in potential allies and associates.
Graihagh - I see and are we biased to then see symmetry elsewhere?
Ben - It's certainly the case that symmetry isn't just attractive in faces. There's quite good evidence now that symmetry tends to be preferred in abstract art, at least among non-professional art critics. And there's even evidence that symmetry might be attractive in things that you can't even necessarily see. So for example, although when we think about symmetry predicting attractiveness in humans, we tend to think about symmetry of bodies, and symmetry of faces. But actually, the voices and even the body odours of symmetric people tend to be more attractive than those of relatively asymmetric individuals. And that kind of ties back again to this idea of symmetry perhaps being attractive because it advertises something about our underlying physical qualities.