Facing Up To It...

Many moons ago I sat  through a lecture on facial recognition.  The lecturer put on the screen  a selection of faces - all blonde ladies. There were 30 pictures and we had to study them for three minutes and say how many women there actually were. I spotted an unusual eyebrow more than once…. 15 times in fact. Ahhhh! I thought, there are only 16 ladies featured. 15 singletons but every second picture was Miss Eyebrow. The lecturer was trying to catch me out.

Of course there were only two ladies…15 pictures of each. Most of the students in our group answered between 15-30 different women. In Holland, students on the same course got it 100% correct. Because the ladies were a Dutch pop star and a Dutch newsreader. So if you ‘recognise’ a face, you are more likely to …err… recognise a face.  

The moral of that story is that you should not be a career criminal if you look like somebody famous.  Unless you bear a remarkable resemblance to another career criminal I suppose.

Facial recognition is fraught with problems. We find it difficult to verbalise specific facial features unless they are odd in some way. It would be difficult to describe George Clooney

                                            

to a another person well enough  for them to recognise who exactly you were describing, but throw in a notable feature like Owen Wilson’s nose,

                                    

 Bruce Forsyth’s chin,

                                          

 Prince Charles’ ears

                                                   

and it becomes easier. Stature, race, height and build are too generic for recognition.

But unfortunately for forensic purposes, most folk are average. Which makes mathematical sense.

The photofit system invented in the 70’s was useful, but not realistic. It suffered  from weird horizontal lines. It was difficult for the witness to  specify a likeness as it relied heavily on single feature recall while our brains use a more holistic system. As humans, we see a face, not a set of eyes, a nose, mouth etc.  We have no memory for those individual features. And there was the obvious problem that there might be no match in the  photo fit system for the witness to use. Does it actually possess Owen Wilson’s nose among its variations. The system was only ever supposed to give a ‘type likeness’, never a recognisable image of the specific features of the person concerned.

Here are some famous folk  by photofit. I managed to guess two correctly.

                                 

Answers below...

And I had a go at photofitting myself. I know my own face reasonably well but it’s c**p isn’t it!

                                                 

Another test?  A  composite picture that consists of the top half of one famous face and the bottom of another. The brain struggles. So automatically we cover top or bottom with our hand and immediately say

 

David Bowie and Harrison Ford

Angelina and Helena

Scarlett and Helen 

                                      

                                                                  Hugh and Meryl

Separated, we can hone in on a feature we recognise but our brain can’t pull that recognisable feature out the composite.

Only the whole face is ever stored in our memories.

You can see it is still problematic – and that is with faces you know well. How accurate would it be for a stranger’s face seen fleetingly, in an emotionally charged situation?

Now there is a more advanced system. The computer gives nine basic images… then hones and morphs the face as a whole, remodelling as the witness says ‘image four is good’,  but eyes more like five. And the computer remodels with the witnesses best guess. Even at that the witness was describing  Dame Judy Dench. The system operator guessed he was trying to describe Jo Brand.

                          

                                                               Jo

                            

                                                            Judy

Recognition we find easy, but recall is not.

2.5% of the population have prosopagnosia – face blindness, including Brad Pitt seemingly. Does that mean I could tell him I  was Angelina and he would  believe me.

‘Monica’ has the condition. Her own daughter was standing in front of her in a bus queue and she didn’t recognise her at all,  until she spoke, and moved.  Monica is drawn to distinctive looking people. She is fine meeting folk for the first time, but when she meets them again she has to rely on them recognising her and saying hello to her.

But then we have contact bias. We recognise best the type of faces that we see every day. Somebody who lives in a white society can discriminate fine details of the ‘white face’ as a whole, but when confronted with an Asian or Polynesian face – they will recognise only the racial features. 

Some bloke who was nifty with a pen wrote this….

Your face, my thane, is as a book where men
May read strange matters. To beguile the time
Look like the time; bear welcome in your eye,
Your hand, your tongue: look like the innocent flower,
But be the serpent under’t.

(from Macbeth, Act 1, Scene 5)

Wouldn’t stand up in court though would it?

The answers....

                             

Caro Ramsay  25 07 2014