Criminal Psychology - Collection and Processing of Forensic Evidence (Biological) Flashcards
Background;
According to Dror et al. these errors in identifying fingerprints can be explained by cognitive biases;
Confirmation bias: This occurs when people observe more, give extra emphasis to, or intentionally look for evidence that would validate their current beliefs. This bias makes people likely to excuse or completely ignore evidence that would contradict their beliefs. The Brandon Mayfield case was a classic example of this bias.
Observer or expectancy bias: this is when the expert anticipates the outcome as a result of information from and initial observer and the outcome (for example, if an officer informs the expert that the suspect has already been identified by an eye witness and the finger print analysis is just needed to confirm their identity)
Selective attention: prior expectation can lead to the ‘filtering out’ of ambiguous elements in a partial or ambiguous print where a ‘close call’ has to be made to create a match.
Conformity effect: if a fingerprint expert is asked to validate the decision of a peer, or of a superior, this effect may unconsciously bias them to agree with the original decision if they are aware of it.
Need determination perception: this bias arises from a strong desire to solve a particular crime.
Overconfidence bias: experts may experience overconfidence bias and this may make them believe that they are always right, even in the face of contradictory evidence. The more experienced and intelligent they are, the easier it is for them to defend their biases and beliefs.
These biases are more likely to occur when the evidence is ambiguous or imperfect. A study was used to investigate these effects, a long side the effects of top-down and bottom-up processes.
Top-down processes: You have evidence about a crime first and then you investigate. The phrase top-down refers to an approach, which starts with the big picture and then fills in the details. The Top Down approach relies on previous experiences of crimes.
Bottom-up processes: You look at the evidence first, then you build a case or theory of what happened. A bottom-up approach which starts with small details and creates the big picture. No initial assumptions are made about the offender. It can be the little details that are often overlooked that can be crucial to the success of a case.
Key Research;
The key research by Hall and Player has investigated whether finger print experts are affected by circumstances of a case (emotional context). The sample consisted of 70 Volunteer finger experts working for Met police fingerprint Bureau with a range of experiences. It was a Lab experiment, independent measures. IV = emotional context, (low = forgery, high =
murder). Materials: fingerprint from volunteer superimposed on a £50 note. Self-report stating
where they work, years of experience and whether they had ever presented evidence in court and whether they had read the context report for this fingerprint. The results showed that There was no significant difference between high and low emotional group. The conclusion that can be drawn from this is that Emotional context affects a fingerprint expert but this does not have any actual effect on their final decisions.
Applications;
Educating detectives, judges and juries and the general public: by educating the following groups of people about the strengths and weaknesses of forensic science it can help people become more aware of its subjective nature and vulnerabilities to bias. For example, in a court case it may be useful for a judge to ask what an examiner knew about the case, and when they knew it.
Cognitive Training: by training forensic examiners to acknowledge and minimise bias. Awareness of bias is an important step in dealing with it, but it cannot be turned off and on by willpower or awareness alone. Training by cognitive experts could make an important contribution in helping practitioners minimise the influence of cognitive bias on their decisions. For example, forensic science education could include training in basic psychology that is relevant to forensic work, such as the aspects of perception, judgement and decision making.
Blind testing: Prevent the Forensic experts to know the context of the crime. This way they will only perform in the way without knowing the emotional context meaning that they will perform truthfully and without the influence of the crimes surroundings.
