Forensic psychology
Forensic psychology

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Forensic psychology

2.4 Comparing E-FIT and EFIT-V

Watch the following video which explores the comparison between E-FIT and EFIT-V.

Download this video clip.Video player: ou_futurelearn_psychology_vid_1014.mp4
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Transcript

[MUSIC]
GRAHAM PIKE
Most of us are familiar with the facial composite images the police use, when searching for the perpetrator of a crime. The police build these faces from witness descriptions.
In this film, we're going to be looking at the Photofit system and a demonstration of the E-FIT system, which relies on constructing a face feature by feature. We'll also look at the newer EFIT-V system, which explores the psychological advantage of recalling a whole face rather than individual features.
Hello Ollie.
OLLIE
Hello.
GRAHAM PIKE
Ok. What we're gonna do now is to create a facial likeness of the image you've just seen and we're gonna do that by using the E-FIT system on this computer here. So I just need you to start off by telling me the ethnicity of the face you saw and the gender?
OLLIE
White Female.
GRAHAM PIKE
So, white female. What type of face shape did the person have?
OLLIE
Small and round, kind of, yeah round.
GRAHAM PIKE
And quite short.
OLLIE
Mmm.
GRAHAM PIKE
And how old would you say the person was?
OLLIE
Sixty.
GRAHAM PIKE
So...
OLLIE
Old.
GRAHAM PIKE
Old. Alright, ok. Now is there anything you can tell me about the hair?
OLLIE
It was grey.
GRAHAM PIKE
Ok, it was grey.
OLLIE
Like man's short hair.
GRAHAM PIKE
Ok. So, grey and short.
OLLIE
It was messy.
GRAHAM PIKE
It was untidy.
So turning to the eyes now, Ollie. First of all, is there anything you can remember about the eyes that you could describe?
OLLIE
They were narrow, kind of slit, and they were old person eyes, and they were dark brown.
GRAHAM PIKE
Now what the system's gonna do is take the information we just provided with those descriptions and it's gonna display a face. What we'll then do is work with the system to alter it, to make it more like the face.
Well faces are actually an odd stimuli. The difference between one face and another is very small. We all have two eyes, a nose, a mouth -so it's very subtle differences between them. So in order to describe you have to be able to bring the face, kind of, into your mind's eye and zoom in on those individual features, and that's very, very difficult to do, and probably the reason that's very hard to do is we don't store faces in our memory as a collection of features. Instead, we tend to store the whole face.
OLLIE
There.
GRAHAM PIKE
There? You sure?
OLLIE
Yeah.
GRAHAM PIKE
Is there anything about the rest of the face? And the eyes? You did say they were narrow and slitty.
OLLIE
Not as much as that.
GRAHAM PIKE
Not as much as that. Well we can make them bigger. Let's have a look for a few other examples.
The situation facing an eyewitness is a particularly difficult one when it comes to describing a face, because the eyewitness, by the very nature, will be describing a face of someone they don't know. If they knew who the person was they would simply say to the police, it was Bob, it was Katie, it was whoever. It was the guy who lives down the road; it's the guy that's in the pub. The only circumstances under which you would be needing a description is when you don't know the person. So therefore, you're describing a face you're not familiar with and we are very bad both at recognising and particularly at recalling and describing unfamiliar faces.
Ok, was there anything else about them? Is that quite a good representation of the face?
OLLIE
I think so.
GRAHAM PIKE
Ok Ollie, that looks like quite a good representation of Joe Brand to me. OH! And it isn't...oh dear. Ok so it's Dame Judy Dench. So when you were thinking about trying to recreate the face were you able to bring that picture to mind?
OLLIE:
Yeah. I thought the eyes and mouth, and the hair, that's all I remember the most.
GRAHAM PIKE
So how difficult did you find the process of trying to recreate the face?
OLLIE
I found it quite difficult. Some of them weren't exact but they reminded me of them.
GRAHAM PIKE
How easy did you find it to describe the features?
OLLIE
Hard. With the selections.
GRAHAM PIKE
Looking at it now and to describe it - do you think it would be an easier or difficult...
OLLIE
Yeah, it would have been easier.
GRAHAM PIKE
That would have been easier... So looking at it now, and say for instance describe the nose to me.
OLLIE
Umm...yeah that would be hard.
GRAHAM PIKE
It's hard isn't it?
We are very bad at describing faces and there are a couple of reasons for that. Perhaps the simplest reason is we don't have the vocabulary to describe individual facial features very well. So if I ask someone to describe a nose, all they're likely to tell me is, well, it kind looked like a nose. They might even say, you know, it's an average nose. But when it comes to hair, we often have a better vocabulary. We can talk about colour, we can talk about length, we can talk about style, but generally when it's individual facial features we just don't have the words available to us to describe the features very well.
The other problem is, to describe something you first have to bring it mind - you have to recall - and we find it very difficult to bring faces to the mind's eye in sufficient detail, in order to describe them. You then have the added problem that you always do with describing face is you then have to communicate somehow, that information, which is visual in nature, which is about how something looks, and to describe it verbally to the police officer. And going from visual memory to the verbal description is quite tricky.
OLLIE
Yeah.
GRAHAM PIKE
What we're going to do now is, once again try to construct a facial likeness of the face that you've just been studying, but we're gonna use a new system rather than the E-FIT. So the first thing is, was it a man or a woman?
OLLIE
A female.
GRAHAM PIKE
And can you tell the ethnicity?
OLLIE
White.
GRAHAM PIKE
And their age?
OLLIE
Fifty-five to sixty.
GRAHAM PIKE
And just an approximate indication there of face shape...?
So the problem for the police then, is they need to come up with a visual image of what the perpetrator looked like. So the first attempts to do this, use sketch artists; so you get an artist to talk to the witness, the witness would describe the face to the sketch artist, who would then produce an initial drawing and adapt it in light of what the witness was saying, to produce a sketch of the perpetrator. The problem with this is first of all it relies on the witness describing the face, which we know is difficult. It also relies on the police having sketch artists that can draw very good images of faces, and that's quite a skill.
The initial technological solutions to this problem were the identikit and Photofit systems, and what they comprised were albums of individual features. The person would look through the albums - there's one here, so you can see there's lots of eyes - they would look through the eyes and they would pick one of the eyes out. They would do the same for noses and the police officer then could fetch from a box of all these features, the noses and the eyes, and then put them all together to form an image like that. Now you can see these are actual photographs of other people's features that have been put together into a composite to try and represent the face of the perpetrator.
There are lots of problems with this, it's got lots of lines on it for one thing, the features don't necessarily, kind of, match up particularly well and researchers found that the accuracy of these likenesses that's produced by these systems isn't that brilliant. However, of course, it's arguably still better than simply putting out a verbal description, because verbal descriptions just really don't contain sufficient information to allow someone to identify the perpetrator.
What we need to do is to try to work out which is the best face. We can also tell the computer which are particularly bad matches, and if two or more of the faces look like possibilities we can morph or blend them together. As we go along, the arrays of faces will become more and more similar to one another.
There are a new generation of facial compositing systems that are beginning to be used by the police, now. All of these systems work off a similar technique and the idea is that you try to minimise the amount of verbal description that's necessary, that the system has to have in order to be able to create the face, and you don't ever require the witness to work feature by feature. Instead, the construction process works more holistically - so you're presented with a whole face and you simply look at an array of nine or sixteen depending on the system, and say which of the faces in front of you is a best match, for your memory of the perpetrator.
So psychologically this is another big step forward. It's, the process of construction is a much better match for how we think human face recognition and human face memory operates.
OLLIE
This one is not a good one.
GRAHAM PIKE
There is a problem in simply trying to come up with technological solutions because the key limiting factor here, the real problem in the equation is human memory. The technology can still be improved further - I don't think we should be complacent - there's always room to develop it further.
OK Ollie, you created the face of Judy Dench again. How did you find the process?
OLLIE
Easier than before. It gave me choices that it had made itself but I think it's good that on the way you could change bits - which I think I should have done - by making her look older and stuff.
GRAHAM PIKE
Before you were saying found it quite difficult. If you remember I asked you to describe the nose in the picture and you found it quite tricky to do?
[MUSIC]
GRAHAM PIKE
Did you notice there was less description?
OLLIE
Yeah, that made it easier.
GRAHAM PIKE
So how do you think you did? Do you think that's better than the...
OLLIE
It's better than before.
GRAHAM PIKE
Technology cannot completely overcome the limitations of the human mind. Even recreating the face of someone we are familiar with is incredibly difficult. And while the differences between the two systems may seem subtle, psychologically we're aware that humans do not remember a face by its individual features. The newer systems, which primarily use whole faces as opposed to features have proved a much better match for how we think human face recognition and human memory works.
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Interactive feature not available in single page view (see it in standard view).

Is it possible to design a composite system based on recognition rather than recall?

In the ‘Comparing E-FIT and EFIT-V’ video Graham worked with a participant to produce a face using E-FIT and then using EFIT-V, which is the latest composite system to be used by the police. As you will see, EFIT-V is designed to try and utilise face recognition, rather than face recall. The design of EFIT-V once again demonstrates how important it is to have psychological knowledge of how the mind works when it comes to police investigations.

Psychological research has helped create composite systems that make the most of human cognition and get the most from the memories of witnesses.

Composites are used by the police to generate leads when they do not have a suspect and are not intended to be used as identification evidence – that is to say that the similarity of a suspect to a composite image should not be used as evidence that they committed the crime.

Once the police have a suspect, they need to use an alternative method to produce evidence that the person is the perpetrator of the crime, such as asking the witness to attempt to identify the suspect in an identification procedure, such as a line-up. It is these alternative methods that you’ll look at next week.

But before you do that, you’ll explore face recognition further in the next section, including hearing from someone with ‘prosopagnosia’, which is a neurological condition that leaves the person unable to recognise faces.

Figure 15
FP_1

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