Topic 2 - Processing Forensic evidence Flashcards
Hall and Player Aim=
- Whether written report of crimes would affect finger print identification-poor quality prints experts
- Whether finger print experts would be emotionally affected by the case
Hall and Player - Sample
- 70 volunteer finger print experts- work for Metropolitan police
-experience 3 months to 30 years - Mean age 11
Hall and Player - Procedure
- Finger prints scanned and superimposed onto right corner of £50 note
- 14 prints made and compared for consistency
- Each participant given 1 of 14 prints- relevant 10 finger prints form from the suspect , crime scene, report and paper advising participants
- All took part in the study as a part of normal working day
- Had access to fingerprint magnifying glass
-Experiment= indépendant measure design - half assigned to low emotional context - forgery
- and half to high emotional context- murder
- Had to fill in demographic information including where they worked and number of years
- Had to identify:
Identification
Not an identification
Insufficient
Insufficient detail to establish identity - Had to provide details of observation and opinions said whether they referred to crime scene information and which part if information affected finger print analysis
Hall and Player - Findings:
- 57/70 =-read report
- 13/70 chosen not to do it
- 52% high emotional context believed it affected decision
- 6% low emotional context believed it had an affect
Hall and Player = Conclusion
Emotional context did not affect ability of finger prints experts when analysing
Miller- The six pack idea
Suggests in same way lineup is used for visual identification of hair sample and finger prints= false positive
- Line up should be done not just 1 comparison
- Gave student 1 hair sample from 1 suspect
- OR 5 samples from 5 suspects
- Referred to as 6 pack
-Reduces biases and pressure when finger prints and hair samples are matching
Linear Sequential Unmasking
LSU
Analyse crime print on it’s own
Look for any unique features and decide if there is enough detail without additional info
Extra information is given in order for comparison
The expert can revisit and add to their analysis but cannot delete or make changes to initial interpretations
Also say how confident in saying how confident in saying it is a match or not
Dror et al- research with 27 students
Non fingerprint experts given 96 pairs
Compare each finger print were clear and easy to match
- Half the finger prints were clear and easy match
- Half ambiguous so top processes a factor
- Some crimes low emotion others high
Photos used to reinforce
- In some emotional cases subliminal message including words “same: or guilty” flashed on computer
Dror- top down biases
Expectancy bias
Selective attention
Conformity effect
Need determination perception
Overconfidence bias
Psychology as a Science
