Harry was a friendly young man, 32, married with a wife and children.
The only problem was that Harry couldn't actually recognise his wife or children--by looking
at their faces.
His wife, for example, had to identify herself to Harry by wearing conspicuous articles of
clothing, like a big red hat.
By taking one quick look at something like...
my face... you can tell my age, gender, race, where I'm looking and even my mood.
And if you've met me before, hello, you generally recognise me in a fraction of a second.
We have this amazing ability to recognise faces--there's even a dedicated area in our
brains for it--but we hardly ever stop to think just how amazing this really is.
For all the new faces we see, our brains figure out how different it is from our perception
of an average face - this is an average of all of the faces you've encountered before.
Our brains reduce the facial features, like eyes or lips, to a point and what we remember
is just the distance and direction of that point from the centre.
This is called face-space, not like the FaceSpace the Oatmeal invented but a vector based mathematical
model of face perception proposed by researchers in the 80s.
It allows us to remember a huge amount of faces, because what we store in our memory
is this code, rather than having a photographic memory for faces as a whole.
Because of this tendency to construct an "average face" from all of ones that we see, we're
more likely to remember distinctive faces from typical ones, like Gollum's huge eyes
or Mr. Spock's pointy ears.
As for people we already know, like our friends, family and even celebrities, something interesting
happens inside our brain when we see their faces.
Researchers recorded lots of single neurons, which are so incredibly tiny, in patients
suffering from epileptic seizures who had electrodes implanted within their skull.
They found that single neurons fired only when subjects were shown pictures of Jennifer
Aniston, or Halle Berry, compared other faces or objects they didn't recognise.
Your neurons aren't lightening up because you're jealous of Jen's hair or love her chin,
it's simply because you recognise her.
This activation of your neurons happens for your friends and families too, it's quite
appropriately called "the grandmother cell".
Some researchers question the existence of such a neuron, but perhaps the neurons firing
is our way of retrieving our face space memory.
Sadly there are times when grandmother won't be there to help.
There are some people, just like Harry, who don't recognise any faces, ever.
People who suffer from this condition, face blindness or prosopagnosia, have a warped
face space.
Most of the time it's due to brain damage in facial recognition areas, Harry actually
sustained head injuries from a car crash, other people are born with it.
It's like people suffering from this condition just can't join the dots, some face blind
people will only recognise those they see very often, some won't recognise anyone at
all.
So things like Facebook are even better at identifying you than some people are.
And facial recognition technology actually uses the face-space principles to work.
This technology identifies you, or me, by measuring things like the distance between
your eyes, the width of your nose, the shape of your cheekbones and the length of your
jaw line.
In other words, your faceprint.
While most of our brains do this intuitively, I hope there's some way for facial recognition
technology to help face blind people to recognise their wife or children in years to come.
So the next time you just can't remember a person's name, be thankful that you can recognise
their face.
And that you don't have to wear this for your significant other to recognise you.
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