Hall and Player: Fingerprint Analysis

What was the aim of Hall and Player’s research?

To explore the impact of contextual bias on fingerprint analysis of ambiguous prints.

1. Are experts affected by a written report when assessing poor quality prints?

2. Are experts emotionally affected by the type of crime?

What is the research method of Hall and Player?

Field experiment - conducted in their normal working offices at the London Metropolitan Police Department (New Scotland Yard).

Procedure: What was the task given to participants?

Each group was given the same fingerprint from a right forefinger and asked to match it to comparison prints on a 10 point scale. The only difference was the high or low emotion.

Procedure: What was the low emotional context?

• Forgery Case at a shop

• Fingerprint was positioned so the background of the bank note obscured some ridge detail (partial print, same for both conditions)

Procedure: What was the high emotional context?

• Alleged murder (fired 2 shots at the shop)

• Fingerprint was positioned so the background of the bank note obscured some ridge detail (partial print, same for both conditions)

What were the results of the experts’ reports?

• 57/70 said they read the report, 30 from the high group

• 52% of the 30 thought they were affected by the report

• Only 6% from the low emotional group thought they were affected

What were the objective results of the study?

• All experts made similar decisions in their judgement, regardless of their emotional context

• Chi Squared found no significant difference in results amongst the contexts

While experts feel affected, there is no actual impact on judgement.

Statistics of the objective results of the study?

(Insert table image)

How is Hall and Player reliable?

• Standardised fingerprint for all participants (right index finger, same printer used)

• Standardised positioning of the fingerprint

• Information gathered from the experts was consistent (shows high external reliability)

How does Hall and Player lack validity?

• experts knew the fingerprint wasn’t from a live case - demand characteristics

• only uses experts from London - lacking population validity

How is Hall and Player valid?

• high population validity - using experts (target population)

• high mundane realism - natural setting

• highly standardised which controls extraneous variables

How is Hall and Player not biased?

Generalisable to the target population as they are all experts.

How is Hall and Player biased?

• Only studied London experts

• Volunteer bias

How is Hall and Player ethnocentric?

• All from London

• Cognitive bias rooted in cultural experience (individualist vs. collectivist)