OCR Psychology - Collection of forensic evidence

What motivating factors can affect solving a crime?

Emotional context + ambiguous fingerprints

What research method did Charlton et al. use?

Semi-structured interviews

What was Charlton et al.’s sample?

13 experienced forensic experts

What did Charlton et al. conclude?

Fingerprint experts can be emotionally motivated to achieve results

What research method did Dror et al. use?

Laboratory experiment

What was Dror et al.’s sample?

27 British university students (9 males + 18 females) with a mean age of 23

What sampling method did Dror et al. use?

Self-selected - however they had to take part (section of course)

What were the results of Dror et al.’s study?

Participants were more motivated by the emotional context (high) if the fingerprints were ambiguous

What is cognitive closure?

When people desire a conclusion to a decision making process

What is the unfounded confidence paradox?

When people are confident that they are correct even when wrong

What is contextual bias?

When details of the crime make the experts biased

How can the role of the persecution / defence lead to bias?

If experts identify with them their decisions could be more biased

What sampling bias is often in the research into collection of forensic evidence?

Student participants are used instead of fingerprint experts

What was the aim of Hall and Player’s study?

To see if trained fingerprint experts are affected by the emotional context of a case

What research method did Hall and Player use?

Field experiment - during their work time at New Scotland Yard Fingerprint Bureau

What were the IVs in Hall and Player’s study?

Low emotional context (forgery) + high emotional context (murder)

How were the participants put into the 2 conditions in Hall and Player’s study?

Random allocation

What were the DVs in Hall and Player’s study?

Whether they matched the fingerprint or not, if they used the crime report + if they felt it affected their judgment

What was the sample in Hall and Player’s study?

70 fingerprint experts with a mean experience of 11 years

What sampling method was used in Hall and Player’s study?

Self-selected sampling

How was Hall and Player’s procedure standardised?

Participants were given a £50 note with an ambiguous print on it, they were given crime reports, they compared the print to 10 other prints + completed a post-experiment questionnaire

What were the results of Hall and Player’s study?

57 / 70 read the crime report, 52% of the 30 who had read crime report (high) thought they were affected by the context + there was no difference between the experts’ judgements

What is a conclusion of Hall and Player’s study?

Fingerprint experts are able to handle evidence in a non-emotional manner + present evidence in court

What lowers the ecological validity in Hall and Player’s study?

Not actual cases, their emotions would be different in real cases

What lowers the reliability of Hall and Player’s study?

Participants were able to speak, do other tasks + come and go as they please

Why is research into the collection of evidence socially sensitive?

It suggests forensic evidence may not be objective + should not be trusted in court

What is an application of Dror et al.’s study?

Training in bottom up processing to reduce cognitive bias

What is an application of Hall and Player’s study?

Restores confidence in trained experts + evidence in courts

What is ACE-V?

A structured approach to fingerprint analysis

What does ACE-V stand for?

Analysis, Comparison, Evaluation + Verification

What happens in the Analysis phase of ACE-V?

Unsolved fingerprints are analysed for patterns

What happens in the Comparison phase of ACE-V?

Known fingerprints are examined to see if they share similarities with the unsolved print

What happens in the Evaluation phase of ACE-V?

Two prints are evaluated side by side

What happens in the Verification phase of ACE-V?

A second expert carries out the previous stages (blind) to see if they reach the same conclusion

Why would ACE-V reduce bias in the collection of forensic evidence?

The blind stage was found to reduce the probability of incorrect fingerprint identification in a crime scene training session 2011

What is bottom up processing?

Analysing the crime scene evidence first, give a confidence rating for the analysis then read crime report

What does bottom up processing avoid?

Confirmation bias

Why would bottom up processing reduce bias in the collection of forensic evidence?

The forensic evidence is interpreted the same way regardless of the context of the crime