2. COLLECTING AND PROCESSING FORENSIC EVIDENCE

Question 1

Bottom-up

Answer 1

Refer to database

Question 2

Top-down

Answer 2

Use own awareness of crime

Question 3

Expectancy bias

Answer 3

Expert anticipates outcome

Question 4

Selective attention

Answer 4

Section that matches previous data/evidence

Question 5

Need-determination bias

Answer 5

Strong desire to solve crimes, may rush analysis

Question 6

Aim of Dror

Answer 6

Investigate whether high emotion context increases likelihood of a match decision

Question 7

Dror sample

Answer 7

Uni students

Question 8

Dror method

Answer 8

Lab

Question 9

Dror procedure

Answer 9

Given pairs of fingerprint images 
See if they matched 
Manipulated crime context (murder= high emotion, theft= low)
Manipulated image (neutral= table lamp, graphic= knife wound on face)

Question 10

Results from Dror

Answer 10

When crime context involved harm= more likely to say ambiguous pairs matched

Question 11

What does Drors research suggest

Answer 11

Need determination bias is created as Ps are more motivated to find match in high emotion context

Question 12

Pros of Dror

Answer 12

Controlled (C+E)
Standardised (replicable)
Quantitative data (objective)
Useful applications- remove context from analysis

Question 13

Cons of Dror

Answer 13

Lacks population validity (uni students)
Reduced ecological validity- no consequences of wrongful match
Demand characteristics

Question 14

Hall and Player aim

Answer 14

Experts from MET fingerprint Bureau show a bias for matching ambiguous prints in high emotion context

Question 15

H+P sample

Answer 15

70 experts
3 months- 30 years experience
Self selected

Question 16

H+P method

Answer 16

Lab

Independent

Question 17

H+P procedure

Answer 17

Deliberately obscure fingerprints on $50 note
Latent print= only just identifiable and an ambiguous match confirmed by other experts
IV- high (murder) or low (forgery) emotion case
DV:
1. did expert read report before matching?
2. did they identify a match?
3. would they be prepared to present in court?

Question 18

H+P results

Answer 18

Very few matches
57/70 read report
High emotion condition- experts affected by report
No link between emotion and analysis of print
most not confident to present in court

Question 19

What does H+P research suggest

Answer 19

Emotional context plays role in feelings, but doesn’t produce top-down processing bias
Experts better than non-experts
Don’t provide context for real life cases

Question 20

Pros of H+P

Answer 20

Useful applications- don't provide context 
High population validity- experts 
Controlled- same equipment 
Standardised 
Independent- reduces DC

Question 21

Cons of H+P

Answer 21

Less generalisable (same type of people)
Lacks ecological validity- no consequences 
Demand characteristics