Hall & Player

• What was the background?

  • Fingerprints have controlled processes such as being completed by 2 analysts independently but no matter how experienced they are still capable of mistakes so it should be verified before reported
  • Been suggested that circumstances surrounding cases & pressure to produce results may influence outcome
  • Protocols by London Met Police services for fingerprint analysis involves providing examiner with report, introducing emotional bias
• What was the aim?

  • To test effects of context on fingerprint identification by fingerprint experts:

  1. Does written report of crime affect fingerprint experts’ interpretation of poor quality mark?
  2. Are fingerprint experts emotionally affected by circumstances of a case (context)
• What was the sample?

  • Self selected
  • 70 fingerprint experts working for the Met police Bureau
  • Length of experience ranged from less than 3 months to over 30 years
  • Majority were practitioners woking on fingerprint teams
  • A minority (12) had managerial roles and were no longer active practitioners
• What was the method?

  • Field / lab experiment
  • IV - low or high emotional context
  • DV:

  1. Whether print was match (identification), not a match, insufficient (not enough detail for comparison), insufficient detail to establish identity
  2. Whether had referred to crime scene report prior to assessment of prints and what they had read
  3. Own judgement whether info in report had affected their analysis & if so how confident would be to present in court

  • Questionnaire - post experiment
• PROCEDURE - Where were prints analysed?

  • In work time and typical fingerprint examination room in New Scotland Yard used
  • Asked to treat experiment as they would in a typical day and not discuss fingerprints - ecological validity
  • No time limits were placed on ppts to complete analysis
• PROCEDURE - Tasks

  • Ppts assigned to high or low emotional context

  Low emotional:

  • Given exam report referring to allegation of forgery, chosen as a victimless crime & carries minor sentence
  • “suspect entered premises & tried to pay for goods with forged 50 note”

  High emotional:

  • Given report referring to murder - has victim & most severe sentence
  • “Suspect fired 2 shots at victim before decamping”
  • Ppts given envelope w / fingerprint of right forefinger & asked their expert opinion to consider whether mark was match with any given on standard 10 print fingerprint form
• PROCEDURE - Post experiment questionnaire

  • When finished, completed demographic info sheet detailing where they worked, how many years experience & whether they had presented evidence in court
  • Had feedback sheet whether or not they had referred to crime scene examination report prior to assessment and if so what info they read
  • Asked if referred to crime scene report and if in their own judgement if it had affected their analysis
• What were the results?

  Effect of written report:

  • Most ppts indicated they read report prior to assessment of prints
  • 52% of 30 high emotional context ppts felt they were affected by the report, significantly more than in the low emotional context where 6% said read report and were affected

  Emotional context:

  • Although some experts in high emotional context thought they were affected by report, this did not affect their fingerprint analysis
• What were the conclusions?

  • Even if expert thinks serious type of crime influenced their analysis the final outcome is not affected
  • Experienced fingerprint experts used in study were less affected by cognitive bias than non experts used by Dror
  • Fingerprint examiners may also consider details of individual crime that are provided with prints as surplus to requirements
  • Some experts stated they did not read report suggesting these experts would not have been aware of crime type context when making judgements
• How does it explain processing of forensic evi?

  • Possible that experienced fingerprint experts from the Met may be influenced by emotional context and open to effects of cognitive bias and could be emotionally motivated to identifications based on contextual info
  • However H&P found no significant difference between high & low emotional context meaning experts able to minimise risk of misidentification due to top-down influences due to high levels of training on contextual influences
  • Experts need updates & regular training on context effects and motivating factors