Crime Topic 2 - The Collection And Processing Of Forensic Evidnece Flashcards
What was the aim of Hall and Player?
To investigate if a written report would affect analysis and if an emotion context would also affect the fingerprint expert
What was the sample in Hall and Player ?
70 volunteer fingerprint experts from the Metropolitan Police Fingerprint Bureau
Experience ranged from 3 months to 30 years
What was the procedure in Hall and Player ?
Received a £50 note with a transposed fingerprint
A sample of 14 indeed at practitioners confirmed it
Participants took part in the study during their normal working day
Given access to magnifying glass and Russell comparator
No time limit
Given a crime scene report which they didn’t have to read if they didn’t want to.
What were the participants given and what were they told to do ?
They either got a low emotion context crime like forging pay for goods or high emotion crime 2 gunshot murder
After analysing the fingerprint they had to state whether it was
A) matched
B) not matched
C) did not have enough detail
D) some agreement but not enough
What were they told to do at the end of the analysis ?
They had to fill out a questionnaire how and why they came to their decision, whether they read the report and whether they thought it would affect their decision
What were results to the study?
No significant difference between the high and low emotion context crime groups
57 out of 70 read the report
52% said that they thought it would affect their decision
6% in low emotion context crime
What were conclusions made?
Emotional context does not reduce fingerprint experts ability to make a final decisions
But for professionals they believe it would affect them
What were the 2 biases Dror studied ?
Bottom up approach and top down approach
What is bottom up approach ?
Use examination of ridges and pattens of the fingerprint to id entity u I que features of a person
What was the top down approach ?
Experts previous experiences and knowledge to make an assumption about the identity of the fingerprints
Top down approach is open to more mistakes from aspects of experts personality, emotional state and expectations.
What was Drors research on students ?
Involved 27 students, 96 sets of fingerprints 1/2 easy match and 1/2 ambiguous
Fingerprints related to low emotional crime or high emotional crime
Had to press a button if it was a match or not
What were results from Drors study ?
49% match for low emotion crime
58% match for high emotion crime
66% for subliminal messages appearing on the screen ‘guilty’ and ‘same’
What did the Linear Sequential Unmasking process involve?
Normally given 2 prints
1) looks at the print on its own recordings any unique features
2) later case report given to help make a comparison
3) they can then revisit and add to their analysis but cannot delete anything, as well as their confidence on the match
What is Millers sick pack idea ?
Similar to a lineup fillers are used including the suspect
Used for hair samples
Thinks less likely to produce false positives
He gave students students either received 1 hair sample or 5 from 1 suspect match to evidence
