You have now left the main British Psychological Website - return to the main site >>
  Back to the Main BPS Site
Home
Return to Main BPS Site

You Are Here: Home > Conference Proceedings > 2010 BPS Annual Conference > Facial identification in an applied setting

 
 

Conference Proceedings

Abstract Details

 

2010 BPS Annual Conference


Conference Venue: Holiday Inn, Stratford-upon-Avon
British Psychological Society

From: 14 Apr 2010
To: 16 Apr 2010
 
 
Symposia/Symposium

Facial identification in an applied setting

Allan McNeill
Glasgow Caledonian University


Establishing identity via a face or facial image is commonplace. For example, within the criminal justice system it is vital to establish that the suspect in the dock is the person who committed the crime and very often this is achieved by comparing the face or facial image of the accused with that of the culprit. Furthermore, this task is performed routinely by: (1) police officers, attempting to match a suspect to a culprit; (2) passport officers, controlling entry at national borders; and (3) surveillance experts, when tracking suspects. However, it is now well known that establishing identity by this method is highly error prone. In this symposium six eminent UK based researchers in this field will present their most recent findings in this area from an applied perspective, with the focus being on improving the accuracy of facial identification in real world settings.

 

Paper 1: When is memory for faces contagious?

Charity Brown & Kate Muir, University of Leeds

Objectives: Misinformation introduced by a co-witness can impair eyewitness reports. The present experiment examines the influence of co-witness misinformation on the quality of a participant’s subsequent face description.

Design: Exposure to co-witness misinformation (discussing the same face vs. different faces) and the participant’s recall criterion in a subsequent face description task (standard vs. forced description instructions) were manipulated in a between-subjects design. Post-hoc analysis of co-witness discussions further categorised participants as adopting a dominant or non-dominant role in the discussion.

Methods: 40 of participants viewed a picture of the same face, or two different faces, but were told they had seen the same face. They then discussed the face’s appearance. Subsequently, participants individually described their target face. Half received ‘standard’ description instructions, permitting participants to establish their own recall criterion, and half received ‘forced’ instructions, designed to lower participants recall criterion and encourage erroneous recall.

Results: Participants discussing different faces were exposed to a greater amount of misinformation than participants discussing the same face; however, subsequent individual face descriptions contained equivalent amounts of misinformation across both conditions. Forced compared to standard instructions elicited more information overall, but equivalent amounts of misinformation. Non-dominant discussants included significantly more misinformation in their individual face descriptions than dominant discussants.

Conclusions: Increased susceptibility to misinformation about a face is not inevitable even when exposure to misinformation is prevalent and a lenient retrieval criterion is adopted. Social factors such as the presence of a dominant discussant may play an important role.

 

Paper 2: Identification on the street: A survey of police use of street identification and other identification procedures

J.P. Davis, University of Greenwich, T. Valentine, Goldsmiths University of London, A. Memon, Royal Holloway, University of London & A. Roberts, University of Warwick

Objectives: Following a crime report, the police in England and Wales may use a street identification (showup) to obtain evidence when there is insufficient evidence to arrest. This may involve encouraging a witness to view an individual, or to conduct an area search of the vicinity. The aim of this research was to survey police use of street identifications, comparing outcomes with alternative visual procedures and to extrapolate national estimates of use.

Design: Case data involving identification procedures were obtained from four police forces. These included street identifications, familiar suspect identifications, CCTV evidence, ‘mug shot’ images, facial composites and video lineups.

Methods: Three types of data were collected. Firstly, diary studies of robbery squad officers provided details of 701 cases involving an identification procedure and their outcomes. Secondly, data of 37 cases in which positive street identifications were followed by a video lineup of the same suspect. Finally, data of 80 cases in which an area search was conducted with or without a witness present in a police vehicle.

Results: A street identification was attempted in approximately 25 per cent of robberies and was the most frequently used identification procedure. Approximately, 12 per cent resulted in a suspect identification. The majority (66 per cent) were later charged or cautioned, particularly if a witness identified the same suspect in a subsequent video lineup.

Conclusions: The police rely on street identification in the investigation of street robbery. Despite a modest success rate, it is more likely than any alternative procedure to result in a suspect being charged.

 

Paper 3: The psychology of face construction: giving evolution a helping hand

Charlie Frowd, University of Central Lancashire; Melanie Pitchford, University of Lancaster; Vicki Bruce, Newcastle University; Sam Jackson, University of Central Lancashire; Gemma Hepton, University of Central Lancashire; Maria Greenall, University of Central Lancashire; Alex H. McIntyre, University of Stirling; Peter J.B. Hancock, University of Stirling

Objectives: To evaluate improvements to a recognition-based facial composite system using face construction procedures which mirror those of policework.

Design: Eyewitnesses traditionally construct a composite of an offender’s face by the selection of individual facial features: hair, eyes, nose, mouth, etc. Research suggests, however, that this method generally produces unrecognisable images when realistic procedures are followed. We have been developing a new system called EvoFIT that works by the repeated selection and breeding of complete faces. Here, two techniques were investigated with the potential of improving system performance. The first blurred the external parts of the face, to help a user focus on the important central region. The second manipulated an evolved face using a set of psychologically-useful scales, to allow a user’s face recognition ability to improve the overall likeness; these so-called ‘holistic’ tools change the perceived age, masculinity, honesty, etc.

Methods: Participants looked at an unfamiliar face and two days later constructed a single composite. They used either EvoFIT, with or without blurring and holistic tools, or a typical ‘feature’ system. Further participants attempted to name the composites.

Results: A benefit was found for each technique, and performance was maximal when both were used together: EvoFIT composites were correctly named 25 per cent on average compared to 5 per cent for composites constructed using the ‘feature’ system.

Conclusions: It is now possible to produce a fairly recognisable image from a fairly weak memory of a face, the norm for real witnesses. A plausible model to account for the enhancements is discussed.

 

Paper 4: An exploration of visual behaviour in eyewitness identification tests

Heather D. Flowe, University of Leicester, School of Psychology

Objectives: The role of internal (eyes, nose and mouth) and external features (hair-line, cheek and jawline) in face recognition was examined in eyewitness identification tests using eye tracking.

Design: Paricipants attempted to identify previously studied faces from either a simultaneous (test faces presented in an array), sequential (test faces presented one at a time), or showup (a suspect face alone was presented) test.

Methods: A total of 36 undergraduates participated for course credit. All had normal or corrected-to-normal visual acuity. Feature dwell time was determined for the eyes, nose, mouth, and face regions by summing up the total length of time spent fixating within the respective region during a test trial. Dwell time data were square root transformed before submitting them to inferential statistical analysis A feature distribution score was also computed for every feature region by dividing feature dwell time for the respective region by total face dwell time. The dependent measures were analysed using the general linear model.

Results: Results indicated that foils were analysed for a shorter period of time in the simultaneous compared to the sequential condition, whereas a positively identified face was analysed for a comparable period of time across lineup procedures. In simultaneous lineups and showups, a greater proportion of time was spent analysing internal features of the test faces compared to sequential lineups.

Conclusions: Different decision processes across eyewitness identification tests are inferred based on the results.

 

Paper 5: Matching to CCTV: The advantage of 3D imagery.

Peter J.B. Hancock & Natasha Tetlow, Department of Psychology, University of Stirling

Matching different images of unfamiliar faces is surprisingly hard, with success rates of only around 70 per cent even in seemingly perfect conditions, using high quality video stills and photographs. We investigated the task of matching a photograph to a video clip, taken in a crowded public location, with the task being to spot the target. The photograph was available for inspection for 30 seconds and then remained present on an adjacent screen during the video presentation. In Experiment 1 we compared a normal photograph with an interactive 3D image; in experiment 2 we replaced the single photograph with an array of stills at different orientations, and added a target absent condition for each target. In both experiments, the interactive 3D display resulted in a significant improvement in matching performance.

 

Paper 6: The Lockerbie bomb: An evaluation of the eyewitness identification of Abdelbaset al Megrahi

Tim Valentine, Goldsmiths University of London.

Purpose: To evaluate the eyewitness evidence in the case, with respect to the research literature on eyewitness memory.

Background: Eyewitness identification provided key evidence in the conviction of Abdelbaset al Megrahi for the Lockerbie bomb. Maltese shopkeeper Tony Gauci identified him as a man who purchased items of clothing from his shop. The prosecution case was that clothing purchased by Mr al Megrahi was traced to a suitcase which contained the bomb that destroyed Pan Am flight 103.

Methods: 20 statements by Tony Gauci, together with supporting documents, press reports and statements by investigating officers were studied.

Conclusions: The effects on human memory of the following factors are relevant to an evaluation of the evidence: Delay, repeated questioning, leading information, repeated identification procedures, and feedback on eyewitness identification. It is not possible to conclude whether the identification was correct or mistaken. It is concluded that circumstances and procedures which have been shown by research to be associated with in increased risk of mistaken eyewitness identification were present in the case.

 

 

 


 

Back to Conference Details

 
Contact Details | Privacy | Legal | Accessibility |
^ Top of Page