criminal psychology topic 2- the collection and processing of forensic evidence

Question 1

hall and player aim

Answer 1

answer 2 qs:
1. does the written report of a crime affect a s fingerprint experts identification of a poor quality print?
2. are fingerprint experts emotionally affected by the circumstances of a case?

Question 2

hall and player sample

Answer 2

70 volunteer fingerprint analysis
independent group design:
half assigned to a low emotional context condition-examination report referring to an allegation of forgery
half assigned to a high emotional context condition- examination report referring to a murder allegation

Question 3

hall and player procedure

Answer 3

1. participants filled in a demographic info sheet stating where they worked, years of experience and if they had ever presented evidence in court
2. completed examination asked to decide if the mark was identification, not identification, insufficient or insufficient detail to establish identity.
3. they elaborated by providing details of their observations and opinions
4. they filled in the specifically designed feedback questionnaire asking if they had referred to the crime scene info and what part, and if this had affected their analysis and how

Question 4

hall and player results

Answer 4

58/70 read the crime scene report, 30 being from the high emotional context
52% who read the high emotional context report said they believed it had influenced their decision, compared with 6% in the low emotion context
no significant difference in outcome was observed between the 2 emotional contexts

Question 5

hall and player conclusion

Answer 5

emotional context did not detract from the fingerprint experts capacity to make a final decision

Question 6

dror et al- research with 27 students

Answer 6

27 uni students given 96 pairs of fingerprints to judge if they matched or not. half were clear and unambiguous, the other 48 were unclear.
either high or low emotional context- shown photos to reinforce context and in some cases shown a subliminal message saying same or guilty on the screen which they had to respond by pressing a button that said same or different.
emotional context significantly impacted judgements from the ambiguous print-matching low =58% high=29%, subliminal message 66%

Question 7

dror- top down biases

Answer 7

false identification 2004: a number of diff experts identified Mayfields fingerprint on a bag (a man linked to madrid bombings)- but it was not him
bottom up approaches use examinatino of the ridges and patterns of the fingerprints without knowing anything else
top down approaches use the experts previous experience and knowledge to make an assumption about the identity of the fingerprints
conc: top down approach more open to mistakes from the experts personality,emotional state and expectations
experts should look at prints out of context to avoid confirmation/emotional bias

Question 8

linear sequential unmasking

Answer 8

opposite of circular dont start looking at both prints
1. look at latent (crime scene) print first and make judgements which you can add later but not delete
2. look at suspect print and do the same seperately
3.. look at any additional info about the crime (unmasking bit) and find info that may help then make comparisons
4. revisit notes and add info point of comparison but do not delete anything

Question 9

miller- the 6 pack idea

Answer 9

taken from ideas of line ups, add dummy fake prints to the mix:
1. have crime scene print-analyse it
2. given suspect print with 5 other dummy prints that are similar to suspect print
miller tested this with students being given either 1 hair sample to compare or 5 hair samples plus the suspect one to match.
miller found it is less likely to produce false positives (misidentification)