Crime Topic 2 Flashcards
What is topic 2
The Collection and processing of forensic evidence
Who is the background research by
Dror
What was the method of drors study
Lab
Who were the participants in drors study (3)
27 uni volunteers
Mean age 23
9 male and 18 female
How many pairs of fingerprints were used in drors research
96 pairs
Half unambiguous so clear
And other half were ambiguous so unclear
What were the 4 conditions
What was the design
Low context - minor crimes with pictures of stolen items
High context - violent crimes with picture of knife wound to victims face
Control - shown nothing
High emotion + subliminal - subliminal messages flashed up before fingerprints like guilty and same
Repeated measures
What are 3 key results from drors study
In high emotion and subliminal - 66% said unambiguous was as match
In high emotion - 58% said unambiguous was a match
In control - 47% said unambiguous was a match
What is the conclusion of drors study
Emotional context can influence h to r likelihood of matching fingerprints even if they are ambiguous
Define contextual bias
When someone has other information outside from that being considered which influences (consciously or unconsciously) the outcome of the consideration
What is confirmation bias
Propel test hypotheses by looking for confirming evidence rather than for potentially conflicting evidence
(Ignore any anomalies that come up)
Who is the key research by
Hall and Player
What was the aim of the key research
To investigate whether trained fingerprint experts make misidentifications due to contextual bias
What was the method and design in the key research
Lab experiment - as realistic as possible
Design - independent measure design
What was the IV in the key research
Whether assigned to low context or high emotional context group
What are the 3 DV in the key research
If they read the scene report prior to examining the fingerprint or after
Whether they’d feel confident sharing the evidence in courts
Whether the fingerprint match was
- an identification
- not an identification
- insufficient detail to establish identity
- insufficient
What was the sample (3)
70 fingerprint experts
Experience of 3 months to 30 years
Work for met police fingerprint buerau
What was the procedure of the key research
They were split into 2 groups - the high emotional context which was a murder case or the low emotional context which was fraud
They were asked to treat the experiment as a typical day at work
They were asked to do feedback sheet after to see if they saw it as a match etc and then if they’d take it to court as well as if the info had affected them or their judgement
What are 3 key results from the key research
81.4% read the report before examining the prints
52% in high emotional context felt affected by info and 6% in low context felt affected
17% in high context said it was identification and would take to court
20% in low context said that
What is a conclusion of the key research
Experts can deal with fingerprint analysis in a non emotional and detached manner
- not a significant difference between high and low context to court
In fact low context higher (20%)
What is the second strategy in reducing bias when collecting and processing forensic evidence
Six pack technique
Proving one known print and one unknown print created expectation bias and leads to confirmation bias
Having the suspect print mixed with 5 other known prints it reduces any expectation that suspect print will be a match with unknown print
What is the first strategy in reducing bias when collecting and processing forensic evidence
Cognitive training
Traininig forensic examines to acknowledge and minimise bias - it can’t be turned off but bh being aware of and then trained bt cognitive experts to minimise influence of cognitive bias.
Ie forensics science training in basic psychology (perception, judgement and decision making)
