Crime-Topic 2-The collection and processing of forensic evidence (Bio)

Question 1

What is meant by Fingerprints and ridge details?

Answer 1

Fine patterns you see on the pads of fingers and thumbs.
Ridge-Line patterns on each finger/thumb.

Question 2

What is meant by fingermark (print)/ latent mark?

Answer 2

can be used to determine they match crime scene print.

Question 3

What is one motivating factor in the processing of forensic evidence?

Answer 3

The sense of reward when a forensic expert had helped to bring closure to a criminal case. motivating factors most often exist when the police and other experts investigate highly emotive cases. the increased level of emotion associated with such crime soften produce a strong desire/motivation to close the case. it is possible that the stronger the motivation the more likely that bias can contaminate any conclusions drawn.

Question 4

What is a cognitive bias?

Answer 4

When someone is not accurate or objective about the way they think about something. There are several types of cognitive bias that might influence whether a “match” is made or not.

Question 5

What is conformity effect?

Answer 5

If asked to agree or disagree with other people (like a supervisor) the expert won’t challenge a previous decision.

Question 6

What is need-determination perception?

Answer 6

If there is a strong desire to solve a crime, the expert may suggest that they have identified a match for fingerprints even when the more accurate outcome is that they cannot solve the crime.

Question 7

What is overconfidence bias?

Answer 7

experts who are overconfident may believe they are always right, even if others disagree.

Question 8

What is expectancy bias?

Answer 8

The expert anticipates the outcome and expects the analysis to come out a certain way.

Question 9

What was the aim and sample of Dror et al (2006) study?

Answer 9

Examined expectancy bias in the analysis of fingerprint analysts.
5 fingerprint experts with an average of 7 years experience each were studied for 12 months as part of their everyday work and were unfamiliar with the Mayfield case.

Question 10

What was the method of Dror’s study (2006)?

Answer 10

Each p was asked to examine a pair of fingerprints taken from a crime scene to see if there was a match. Each p had actually seen the fingerprints 5 years previously on a real case and recorded them as a definite match. In this study, ps were told they were wrongly identified and the expectation was that there would be no match

Question 11

What were the results of Dror’s study (2006)?

Answer 11

4 out of 5 changed their decision that the fingerprints were matched. Three even claimed it was a definite mismatch

Question 12

What was the conclusion of Dror’s study (2006)?

Answer 12

This shows that the contextual information (like the expectation given to the ps) stops experts from giving reliable information and that expectancy bias was truly at play.

Question 13

What was the aim and sample of Dror et al (2005)

Answer 13

Emotional context: manipulated the ps emotions regarding the processing of fingerprints in criminal cases. 27 university students (non-fingerprint experts) were given 96 pairs of fingerprints. Half were clear and relatively easy to match, the other half were more ambiguous.

Question 14

What was the method for Dror’s study (2005)

Answer 14

given 96 pairs of fingerprints. Half were clear and relatively easy to match, the other half were more ambiguous. the fingerprints were related to crimes-some crimes were low emotion e.g.bicycle theft, while others were high emotion e.g.murder//. Photos of the crime scene were also used to reinforce each type of crime. Ps had top press a button either for ‘same’ or ‘different’ to indicate whether they the thought the fingerprints were a match or not.

Question 15

What were the results of Dror (2005)?

Answer 15

Showed that when ps were shown high emotional cases they were more likely to find a match (58%) compared to low emotional cases (49%) especially when the prints were ambiguous. this suggests that an emotional context does influence fingerprint analysis.

Question 16

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

Answer 16

The aim was to see if fingerprint experts in the Metropolitan police can make the decisions about the match of prints when exposed to high-emotion background material.
looked at if this would bias material.

Question 17

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

Answer 17

Lab experiment

Question 18

What was the IV and DV of Hall and Player’s study?

Answer 18

IV-emotional context- low emotion condition (referred to forgery which said ‘suspect entered premises and tried to pay for goods with a forged £50 note. The forgery spotted by cashier. Suspect then decamped.’) and the high emotion context read the same except the last sentence which read: ‘suspect then fired two shots at the victim before decamping.’
DV- Whether the analysts reported feeling affected by the context- creating scenarios and whether this affected their final decision.

Question 19

outline the sample of hall and Player’s study

Answer 19

70 fingerprint experts working for the metropolitan police fingerprint bureau whose experience ranged from less than 3 months to over 30 years (mean=11yrs). most dealt with crimes ranging from burglaries to terrorism although 12 were managers (not active practitioners but on the UK register. All were volunteers who responded to take part in an experiment. The data collected was recorded anonymously using a unique reference number for each expert.

Question 20

What experimental design was used in Hall and players study?

Answer 20

Independent measures design

Question 21

Summarise the procedure used in hall and Player’s study

Answer 21

Ps looked at a fingerprint on a £50 note. This was an image that was scanned and superimposed. the latent mark was thus only identifiable.
each p was given an envelope with a test mark card, the 10-print fingerprint and the examiners report. They also had a fingerprint magnifying glass and a Russel comparator to compare images.
Assigned to groups of 8 and asked to treat the experiment like a normal case.
Ps were assigned to wither low-emotional context or high emotion context. After their analysis, the experts were asked to make a judgement about the print as they normally would.

Question 22

How many ps read the crime scene report overall in hall and Player’s study?

Answer 22

57 read the crime scene examination report
30= high emotion context read the report but 35 in group
27=read the low emotion context report but 35 in group.

Question 23

In Hall and Player’s study what did they find about the perceived effect of the crime scene report in the high and low emotion context groups?

Answer 23

52% of the 30 who had read the high emotion context scenario felt affected by the information compared to 6% in the LEC. Indicating a relationship between the type of context and the perceived effect on experts.
BUT the final decisions made by the experts were similar for the two emotional contexts and no significant difference was found.

Question 24

What conclusions can we draw about fingerprint analysis in relation to hall and Player’s findings?

Answer 24

Emotional context does affect experts’ feelings but it does not influence the final outcome of their analysis. In comparison to the findings of Dror et al (2005), this shows that experienced fingerprint experts are better at doing analyses in a detached manner.

Question 25

What is the application of blind testing mean?

Answer 25

In line with the evidence from Dror et al (2005) the forensic examiner should be unaware of the information about the case that might influence them and should avoid contact with the victims and their families. they should investigate evidence without context. being aware of such information could lead conformation bias.
Also if the expert is verifying a decision someone else had made they should also be blind to the conclusions of the initial examiner and even of who the examiner is, as this may result in conformity bias.

Question 26

What is the filler control application?

Answer 26

The examiner should be given not just one sample print for comparison but 6, consisting of the comparison print (from the suspect) and 5 plausible alternatives or ‘fillers’. Similar to line ups for eyewitnesses. the examiner is ‘blind’ to the information about which print belongs to the suspect.
by removing the focus on one particular print that might potentially be the suspect’s, this means the examiner can be more objective.
Research by Miller (1987) has shown that a ‘line up’ procedure for analyzing hair samples was less likely to produce false positives (misidentification) than the standard process= expectancy bias