File

January 8, 2018 | Author: Anonymous | Category: Social Science, Law, Criminal Justice
Share Embed Donate


Short Description

Download File...

Description

MAKING A CASE Interviewing Witnesses: FACE RECOGNITION

Look closely

1

5

2

6

3

7

4

8

Radovan Karadzic 

Trying to evade capture for war crimes in Bosnia he let his hair grow and wore spectacles. He was able to live and work for 12 years in his country unrecognised even though he had been their leader!

Change of appearance 

Recognition of faces is poor if the face changes between the encoding and the presentation of possibilities.  This could be a change in glasses, hairstyle, beard or even expression.

Studies of face recognition 

  

 

Patterson and Baddeley (1977) compared the accuracy of recall of a face that had changed in some way between the first and second time the participants saw it. The accuracy of face recall is influenced by: length of time since the face was seen the seriousness of crime the number of previous encounters with the suspect witness characteristics (like attention to detail).

Case study: 

George Ince was a known gangland armed robber with links to the Kray brothers. In 1972 he was tried for a murder in a case that rested almost entirely on identification evidence. The witnesses were the husband and daughter of the murdered women who saw the attacker for at least 20 minutes. The daughter identified Ince from an ID parade, but it later transpired that she had earlier been shown his picture contravening the 1969 regulations for the conduct of ID parades. In 1974 after 2 trials Ince was discharged as he was able to produce an alibi. This case highlights the issues that arise with the investigative process & opens up some areas for investigation

Photo fits 





Photo fits were first introduced in the UK in 1970 They involve trained operators selecting alternatives for specific facial features to match a witness’s verbal description, until they have produced a likeness.

Accuracy of Photo fits 

This photo fit of Peter Sutcliffe (the Yorkshire Ripper) was given by one of the women he raped  The picture on the right is a photograph of him taken shortly before his arrest

Advantages & Disadvantages: 

Been found to be very accurate in many cases  Use own memory not multiple choice



Christie & Ellis found to be less accurate than verbal descriptions

Mugshots 



When witnesses experience problems recalling faces they may be presented with a ‘mugshot file’ a collection of photos of people already known to the police, on the assumption that these photos may act as a prompt.

Advantages & Disadvantages: 

May help prompt memory / description as features  Can save time if suspect already know to the police



Feel under pressure to choose even if not confident  Static picture not the same as live

Show ups 

A show-up is the presentation of a photo of one suspect for the witness to identify  This is the least satisfactory form of identification. 

DISADVANTAGES:  

May be led to believe the police are very confident Yarmy found only 57% of people where able to identify someone from 2mins earlier

Photospreads 





A photospread is more effective than a show –up, as it involves the presentation of at least 12 faces all resembling the suspect. Photospreads would tend to be used in situations where the police have a suspect in mind, but need a witness to confirm the identification. A typical procedure would involve a witness viewing an array of perhaps twelve photographs and being asked if they recognised anyone in the array. If the witness indicated that they did recognise anyone then they should be asked to say which photograph they recognise and from where.

Advantages & Disadvantages: 

Fairer than a show up  Suitable for young nervous witnesses



Static photos  Multiple choice affect  Appearance of foils may reduce functional size

Identification Parades (Line Ups) 



Perhaps the best-known type of formal identification process is the identification (or ID) parade. A suspect stands among a number of innocent foils and a witness is asked to inspect the parade and then to decide whether the perpetrator is present.

Advantages & Disadvantages: 

Live better than photo



Multiple choice affect  Appearance of foils may reduce functional size  Distressing for witnesses  Behaviour (i.e. nervousness) of suspect = easier to identify

Face recognition Without conferring – write down the names of the following twelve celebrities.

Condition A 1

2

3

4

Condition A 5

6

7

8

Condition A 9

10

11

12

Answers - A 1 Amanda Holden

2 Brad Pitt

3 4 Katie Price David (Jordan) Tennant

5 Gordon Brown

6 Cheryl Cole

7 Johnny Depp

8 Lindsay Lohan

9 Mylene Klass

10 Peter Andre

11 Nicole Kidman

12 Simon Cowell

Condition B 1

2

3

4

Condition B 5

6

7

8

Condition B 9

10

11

12

Answers - B 1 Peter Andre

2 Mylene Klass

3 Simon Cowell

4 Nicole Kidman

5 Cheryl Cole

6 Gordon Brown

7 Lindsay Lohan

8 Johnny Depp

9 Brad Pitt

10 Amanda Holden

11 David Tennant

12 Katie Price (Jordon)

Results People find it easier to recognise the top half of the face, rather than the bottom half.  Why do you think this is? 

True or False 1 You need to know 5 aids to recall  We are better at remembering faces then snowflakes and inkblots  Photo fits were first used in the UK in 1980  2 types of photo fit system are Mac a Mug and Evofit  Mugshots are where one photo is given to a witness 

True or False 2 Mugshots lack ecological validity  Show ups are the least satisfactory form of identification  Only 57% of witnesses were able to accurately identify a person seen 2 mins earlier in a show up  At least 10 photos are used in a photospread  Photospreads and show ups are susceptible to the Multiple Choice Effect 

True or False 3 ID parades are more suitable than show ups for young and nervous witnesses  Cutler & Penrod did a study of a special kind of ID Parade called a sequential line up  Sequential line ups reduce the multiple choice effect  Most studies of photospreads use arrays which do not contain the target 

True or False 4    

 

Photospreads need to be available in court Photospreads are live, ID Parades use photographs Defence council prefers foils who are different in appearance to the accused The behaviour of the accused may make him or her easy to distinguish from foils If a foil is picked out of an ID Parade they are arrested ID parades may be more stressful than the actual event according to anecdotal evidence

Poor quality CCTV images are still recognisable Crimewatch etc broadcast appeals directly to people who know the suspect 3. Implications for facial reconstruction/ e-fits for approach used 4. Vital components for e-fit. Operators highly trained to extract relevant info 5. If suspect is seen in poor or side light they may look very different therefore influencing testimony 6. Facial reconstruction static – future developments needed 7. Everyone seems to have the ability to recognise faces – implications for credibility of children as witnesses 8. Implications for reconstructions which tend to be expressionless 1. 2.

Recognising and recreating faces by E-fit Key study: Bruce et al. (1988)

Aim  To investigate the relative recognisability of internal and external features of a facial composite.

Method  Three laboratory experiments.

BRUCE 

RECOGNISING FACES 

Internal and external features



Internal features: 



The region including the eyes, brows, nose & mouth

External features: 

Head shape, hair & ears

Participants 1st Experiment – 30 staff and students from Stirling University, paid £2, 15 male, 15 female, mean age 29  2nd Experiment – 48 undergraduates at Stirling University, all volunteers, 21males 27 females  3rd Experiment – 8 staff and students from Computer Science and Psychology 

Procedure: Experiment 1 

The stimuli were target photographs of ten celebrities and 40 composite images produced by E-Fit, PRO-fit, Sketch and EvoFIT.  Each face was clean shaven and spectacles were avoided.  Three sets of composites were used: ‘complete,’ a set containing the internal features and another set containing the external features.

Procedure: Experiment 1 (cont.) Participants were tested individually on one of the three conditions (independent measures design).  They were asked to place each composite in front of a celebrity face in their own time until the task was completed. 

Experiment 2 

 



This experiment used a photo array or photo line up with distracter faces or foils making the task more difficult. The faces and foils were made easy (all very different) or hard (all very similar) to identify. The composites were then presented one at a time along with the photo array and the participant had to pick out from the array the celebrity face which matched the composite. As before, the composites were either of internal features or external features of the face.

Results Experiment 1  Whole composites and those of external features were sorted similarly at approximately 35% correct. The composites of internal features were only 19.5% correct. Experiment 2  Composites of external features (42%) were identified more easily than internal features (24%) and this was consistent across array type (whether easy or difficult). Experiment 3  For both groups the external features were much better reproduced in the composites

Conclusions 

In experiments 1&2 participants performed just above chance with internal features on the tasks used. In all cases participants performed equally well with external features or whole faces  This could indicate that there is something about the internal features of a face which do not work well when trying to create a reconstruction.  This effect holds true even when the face is familiar which sheds some doubt on previous research.

View more...

Comments

Copyright � 2017 NANOPDF Inc.
SUPPORT NANOPDF