Forensic Evidence - We Are Only Human

Forensic evidence can contribute positively to the criminal justice system, but acknowledgements should be made, and precautions taken

By Jessica Young, Featured Writer.

Forensic evidence refers to evidence obtained through scientific methods such as DNA testing, fingerprint analysis, blood samples and so on.

Since Goddard first utilised ballistics in 1835, connecting a bullet to a murder weapon, the use and elusion of forensic evidence has climbed. If you were told your neighbour has been arrested for murder, the police have found their fingerprints on the murder weapon and their DNA strands on the victim, what would you think?

The CSI effect encompasses how as individual’s we are inclined to trust and believe in forensic evidence - if the science points that way then it must be so? With TV programmes and media misrepresenting the reliability and validity of such evidence, there are misconceptions as to the surety of forensics. This has catastrophic consequences as highlighted by the Innocence Project (2020), 45% of wrongful convictions in the US can be related to misuse or misunderstanding of forensic evidence. The victim of the crime is not necessarily the only one to pay an unfair price.

Whilst forensics such as DNA can be extremely useful and utilised in a positive manner such as to release those wrongfully convicted, there have been numerous high-profile mistakes. In recent years the FBI’s rigorous pursuit of Branden Mayfield in response to the 2004 Madrid bombings is one such example. Despite fifteen other potential fingerprint matches being identified and against Spanish authority’s agreeance, the FBI arrested and detained Mayfield for two weeks, later released without charge. After international persecution in the media, Mayfield stood centre stage for the wrong reasons.

Nevertheless, forensic evidence can contribute positively to the criminal justice system, but acknowledgements should be made, and precautions taken. We are only human. There is no such thing as an absolute science when the collection, interpretation and analysis of evidence falls upon human shoulders. Our judgements are subjective and not necessarily reliable nor valid.

This article outlines how it is important to be aware of the different influences and biases that can play a devious role in-relation to the processing and utilisation of forensic evidence.

There are a variety of motivational factors that can influence human behaviours, for example: our own ambitions, personal gains, and even subconscious desires. This can be seen in any aspect of our lives but particularly in-relation to our jobs and careers, we work to achieve gains in our individual ways. New promotions. Monetary gains. Pride and gratification.

Research has indicated that such underlying motivations are prominent in the work of those handling forensic evidence, thus analysis can be influenced. Charlton et al., (2010), interviewed experts within the field of fingerprint analysis using semi structured questions to obtain personal insight into the driving factors relating to their work. Fingerprint analysis has been a key pillar of forensic evidence for over 100 years, yet it is associated with potential biases regarding the element of human interpretation. Charlton highlighted five main motivational associations including reward, satisfaction, fear, and need for closure. For example, individuals highlighted how their job entails “working towards an end goal”, in some ways painting print identification as a means to an end, with satisfaction and reward resting upon a match. Therefore, individual’s may be more inclined to find a match due to the influence of motivational factors. Whilst this study was conducted with a small sample, you can understand how these elements can impact the way we work in our employment.

However, the misplaced trust in the reliability and validity of fingerprint analysis can have negative repercussions. The McKie case indicated in Charlton et al., (2010), is a notorious example in which a lady was arrested for perjury on the stand for claiming a set of prints were not hers. Which were in fact later found to be invalid. There has been a wealth of further research and some measures taken since Charlton’s study to counter such influences.

Though, we must be aware that despite the ‘scientific’ label associated with forensic evidence such as fingerprints, our part in the process opens opportunity for motivational biases.

Our cognition relates to our mental processing, storing and utilisation of information. Decisions made utilising information from the world around us through our cognitive processes, are prone to human error. An inherent part of the way humans mentally process is that of cognitive contamination (Jeanguenat et al., 2017), referring to the impact of biases and errors.

The questionability of forensic evidence does not relate solely to fingerprints, but also to DNA. Individual’s decisions in-relation to DNA identification and matching can be influenced by the obtaining and processing of contextual information. One such phenomenon is that of target or suspect driven bias, in which individuals work from information obtained relating to the crime or suspect to understand the evidence at hand. This can contribute to bias as evidential information is processed and utilised, according to suspect information. Jeanguenat (2017), highlights several cognitive biases that should be addressed when working with DNA processing and analysis - target driven bias being a key area. Contextual information can influence decision making, this relates to how our cognitive processes handle and utilise information. DNA related information may be processed, stored and utilised considering pre-existing information. Identifying flaws in this manner enables measures to be taken to be made to ensure constructive progress.

Dror (2005), indicates that there are bottom-up processes (working from the data  and patterns up to other information to formulate a decision), and top-down processes (working from external and contextual information down to the data to formulate a decision), relating to fingerprint analysis. Dror suggested that cognitive biases such as expectancy bias, confirmation bias, selective attention, and over-confidence can have an impact upon top-down processing. However, if data and patterns are clear, they are not overridden by biases. For example, if analysers are aware one of the prints belongs to someone with previous conviction for GBH and the print in question is related to a GBH case, this can influence their interpretations due to expectation bias (though, according to Dror, not so if the data and patterns are clear).

Thus, there are vulnerabilities to bias in-relation to the human analysis of forensic evidence as our cognitive processes and decision making are vulnerable to errors.

Forensic evidence is predominantly utilised in-relation to occurrences of crime to be presented in court proceedings to determine innocence or guilt. Crimes can vary in severity and harmfulness; from vandalising someone’s car to the brutal murder of an unsuspecting victim. Likewise, the emotions evoked by the account of the crime can be of different intensities. What do you feel in-response to hearing of the vicious attack of an elderly man, resulting in his painful and slow death? Versus, hearing that a group of teenagers graffitied obscenities on someone’s wall?

Emotions can impact our ways of thinking and our actions, for example in-relation to mental state the five areas model highlights an interactive relationship between situations, thoughts, feelings, behaviours, and physical reactions (NHS, 2019). We are a cycle of interconnection and interaction; emotions can interact with other elements. Suggesting that the way crime related information makes us feel could impact the way in which we behave in-response.

Though research has been varied and limited in identifying emotional impact relating to forensic processing, there are indications that there is an impact worth acknowledging and studying further. Hall and Player (2008), compared the impact of crime context relating to fraud (cold condition: less emotional) versus murder (hot condition: more emotional), finding that 70 experts perceived the varying emotional impact to alter their perceptions of the fingerprint analysis. They thought their decision making had been impeded. Though identification of fingerprints was not swayed, crime context appears to alter perceived experience and emotional intensity as further supported by Osborne (2016).

Humans are social and emotional beings, inevitably contextual information relating to traumatic incidents and crime is going to have some impact. Further research can help to identify the ways in which this impact plays out.

Recognisably, forensic evidence is subject to flaws in-relation to the human involvement in the processing and analysis. We are only human. The ways in which we handle and process information and means we are inherently vulnerable to motivational influences, cognitive biases, and potentially emotional impacts. This raises questions in-regards to the level of reliance placed upon forensic evidence in real world applications such as in court cases. Despite the need for greater awareness and acknowledgement of potential issues, forensic evidence can be adapted and evolved in the ways it is handled to limit impacts and continue to contribute positively.

‘(a) and photographed using DCS-3 (b) and that image is then digitally enhanced to give a final black and white image (c) which is best for detailed examination’ (The Open University, 2020)

It should be recognised that perfect science does not exist when imperfect beings such as humans are involved in the processes. However, by raising awareness of the flaws in forensic evidence steps can be taken to help reduce the potential influences and biases, and to limit potential fallout impact upon individual’s lives.

References

Charlton, D., Fraser-Mackenzie, A, F, P. and Dror, E, I. (2010), ‘Emotional Experiences and Motivating Factors Associated with Fingerprint Analysis’, Journal of Forensic Sciences, vol. 55, no. 2, pp. 393 [Online]. Available at https://onlinelibrary-wiley-com.libezproxy.open.ac.uk/doi/full/10.1111/j.1556-4029.2009.01295.x (Accessed 11th May 2020).

Dror, E, I. Péron, e, A. Hind, S-L. and Charlton, D. (2005), ‘When emotions get the better of us: the effect of contextual top-down processing on matching fingerprints’, Applied Cognitive Psychology, vol. 19, no. 6, pp. 799-809 [Online]. Available at https://web-b-ebscohost-com.libezproxy.open.ac.uk/ehost/detail/detail?vid=0&sid=2ce16d89-23b8-47da-9cb2-ca49dda7ba1c%40sessionmgr103&bdata=JnNpdGU9ZWhvc3QtbGl2ZSZzY29wZT1zaXRl#AN=18277502&db=a9h (Accessed 11th May 2020).

Hall, J, L. and Player, E. (2008), ‘Will the introduction of an emotional context affect fingerprint analysis and decision-making?’, Forensic Science International, vol. 181, no. 1, pp 36-39 [Online]. Available at https://www-sciencedirect-com.libezproxy.open.ac.uk/science/article/pii/S0379073808003551 (Accessed 11th May 2020).

Innocence Project (2020), Overturning Wrongful Convictions Involving Misapplied Forensics [Online]. Available at https://www.innocenceproject.org/overturning-wrongful-convictions-involving-flawed-forensics/ (Accessed 11th May 2020).

Innocence Project (2020, b), Policy Reform [Online]. Available at https://www.innocenceproject.org/policy/ (Accessed 11th May 2020).

Jeanguenat, M, A., Budowle, B. and Dror, E, I. (2017), ‘Strengthening forensic DNA decision making through better understanding of the influence of cognitive bias’, Science & Justice, vol. 57, no. 6, pp. 415-420 [Online]. Available at https://www-sciencedirect-com.libezproxy.open.ac.uk/science/article/pii/S1355030617300898 (Accessed 11th May 2020).

NHS (2019), Cognitive behavioural therapy (CBT). [Online]. Available at https://www.nhs.uk/conditions/cognitive-behavioural-therapy-cbt/how-it-works/, (Accessed 11th May 2020).

Osborne, K, P, N. and Zajac, R. (2016), ‘An Imperfect Match? Crime-related Context Influences Fingerprint Decisions’, Applied Cognitive Psychology, vol. 30, no. 1, pp. 126-134 [Online]. Available at https://web-b-ebscohost-com.libezproxy.open.ac.uk/ehost/detail/detail?vid=0&sid=46f58a4c-cbf6-4005-b749-291994b22799%40pdc-v-sessmgr01&bdata=JnNpdGU9ZWhvc3QtbGl2ZSZzY29wZT1zaXRl#db=a9h&AN=112335662 (Accessed 11th May 2020).

The Open University (2020), The use of new technologies in fingerprint matching [Online]. Available at https://www.open.edu/openlearn/health-sports-psychology/health/forensic-science-and-fingerprints/content-section-1.2.4 (Accessed 11th May 2020).