Topic 2: The Collection & Processing of Forensic Evidence: Additional Studies

Question 1

Describe Dror’s ‘bottom-up fingerprint analysis’ concept.

Answer 1

Bottom-up fingerprint analysis: Focuses on detailed ridge and pattern examination. Data-driven and objective, minimising bias.

Question 2

Describe Dror’s ‘top-down fingerprint analysis’ concept.

Answer 2

Top-down fingerprint analysis: Used when prints are of poor quality. Context and prior knowledge influence matching decisions.Susceptible to selective attention bias.

Question 3

Describe Miller’s ‘six-pack’ idea.

Answer 3

• Hair analysis can reduce false positives using a line-up procedure.
• This involves comparing evidence hair to multiple suspect samples, not just one.
• A study tested this by having students compare hairs to one or five suspect samples to limit bias.

Question 4

(Dror: 27 Students) What was the aim of the study?

Answer 4

To examine the impact of emotion on fingerprint analysis.

Question 5

(Dror: 27 Students) Who were the participants?

Answer 5

27 university students (non-fingerprint experts).

Question 6

(Dror: 27 Students) What materials were used?

Answer 6

• 96 fingerprint pairs (half clear, half ambiguous).
• Crime-related images (low or high emotion).
• Subliminal messaging (“same”/”guilty” in some high-emotion cases).

Question 7

(Dror: 27 Students) What was the procedure?

Answer 7

Participants matched fingerprint pairs as “same” or “different.”

Question 8

(Dror: 27 Students) What were the results?

Answer 8

• High-emotion context led to more “same” matches (58%) than low-emotion context (49%).
• Subliminal messaging further increased “same” matches in high-emotion cases (66%).

Question 9

(Dror: 27 Students) What was the conclusion?

Answer 9

Emotional context influences fingerprint analysis in non-experts.

Question 10

(LSU) What does LSU stand for?

Answer 10

Linear Sequential Unmasking.

Question 11

(LSU) What is the first step in the linear sequential unmasking (LSU) approach?

Answer 11

Analysis of the evidence on its own, focusing on unique features and detail for comparison.

Question 12

(LSU) What potential bias is present during the initial analysis?

Answer 12

Selective attention bias.

Question 13

(LSU) How is additional information presented in LSU?

Answer 13

In order of importance to the case, to aid comparison.

Question 14

(LSU) What are the rules regarding revisiting and changing initial interpretations?

Answer 14

Experts can revisit and add to their analysis, but cannot delete or change initial interpretations.

Question 15

(LSU) What can experts state about their conclusions?

Answer 15

They can express their confidence level in the match or non-match, reducing overconfidence bias.