Why do we look like this?

Copyright: BBC

Well to find the answer Richard visits Professor David Hopkinson a geneticist from University College London, who’s been analysing hundreds of faces over the past two years…

Richard: I’m assuming this is some sort of scanner, so what are you doing with it, and, why?

David Hopkinson: This is a 3D face scanner and what we’re trying to do is to capture something like thirty thousand data points, which would allow us to construct this person’s face, in a 3D image on a computer screen. What we’re trying to work out, is the relationship between the shape of her face, and her genetic constitution.

Richard: Why have you got Shelly’s son and mother here?

David Hopkinson: To find out how much influence our genes have on our appearance and see which facial features are inherited factors.

Richard: What use is this going to be?

David Hopkinson: Well, it’s useful in the medical sense, because it gives us information about normal features development, which might have some impact on studies of abnormalities of development. But also there is a forensic use, if for example, at a scene of crime, we took a DNA sample from a blood stain or other biological sample to analyse we could make some prediction about the appearance of that individual.

Richard: You mean even from a blood stain you could tell what someone looks like?

David Hopkinson: Yes in principle.

But what about looking at our faces in a mathematical way, how can our appearance have any relevance to numbers, Richard meets Dr Chris Solomon at Kent University…

Dr Chris Solomon, Kent University

Richard: So tell me Chris, why does the way we look all boil down to a mathematical calculation?

Chris Solomon: The basic idea Richard is that we start with an average face. The face you see here is in fact the average of a sample of about five hundred faces. Essentially when you have a digital image, the grey scale is mathematically quantified. So for example, dark areas in the image tend to have low values. You then average the number lying in each of these groups.

Richard: This image looks too perfect to be average to me.

Chris Solomon: The subjective impression of the attractiveness of a face is in fact related to how close it is to the average face. In other words the closer a face is to the average face, it’s actually perceived as being more attractive.

Richard: Is it possible then, that there could be someone else who looks exactly like me?

Chris Solomon: I suppose from the mathematical point of view it’s possible, although I have to say that statistically speaking it’s unlikely.

Richard: What uses can this system have for us?

Chris Solomon: If it’s possible to specify somebody’s face by a combination of these faces, then all we really need to know is the set of numbers, which can tell me how much of each face I need to produce, we can then use this for numerous purposes. Such as a credit card, where there is just enough space to store the facially encoded image on the magnetic stripe. So for example when you present your card to the cashier to pay for something, as soon as they swipe the card through a magnetic stripe they can match the image, which is produced by the card, to the image of you, the holder of the card.

Richard: So you’re saying Chris that a face can be boiled down to a mathematical equation.

Chris Solomon: That’s absolutely correct yes.

Richard: I’m not sure that I’d want my face imprinted on all my credit cards even although I understand the security implications, but I do think I’m beginning to understand, how it is that I can recall or remember a face, even though I don’t remember the name.

Next stop Galton laboratory, part of University College London named after Francis Galton, a nineteenth century explorer and scientist who believed it was possible to determine people’s character from the way they looked, be they a soldier, farmer or lawyer…

Richard: What have you done to the scans you did, since we last saw you? David Hopkinson: Well we’ve got them ready for more detailed analysis. I’ll show you, first of all this is Shelly’s mother and then on the next screen Shelly. What we’re looking at here is the geometry of the face. We’ve divided the face up into areas which are symmetrical peaks (the red colour) and symmetrical depressions, we can now look for features that we might be able to see in both. For example this little red band across the nose, which we can see in Shelly can also been seen in her son’s face.

Richard: Now you’ve analysed the family, what do you do with that analysis?

David Hopkinson: We put the data together from one individual family with data from other families, so that we gradually build up a pattern of information, which tells us whether we’ve actually selected a feature which shows whether it’s a genetically determined factor. In other words, if we see it in a parent, we will see it in approximately half of the offspring. It gives us an idea of how many genes are involved in determining the facial features. It will tell us, whether this is a problem capable of solution.

If you would like a taste of biology then course S204 Biology:Uniformity and Diversity should suit you down to the ground

If you would like to find out more about these subjects, here are a few suggestions.

Books

Two-And Three-Dimensional Patterns of the Face
A K Peters

Intelligent Biometric Techniques in Fingerprint and Face Recognition (CRC Press International Series on Computational Intelligence)
L. C. Jain, CRC Press

The Art of Genes
Enrico Coen, Oxford Paperbacks;

Human Facial Expression : An Evolutionary View
Alan J. Fridlund, Academic Press Inc

Weblinks

For more information on David Hopkinson and the Galton Lab looking at the characteristics of the face

Also on this site: You can join Raj Persaud as he takes a look at the importance of first impressions and Louise Jameson as she finds out what’s really behind autobiographies