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Monday, November 27, 2006

The purpose of the Detail is to help keep you informed of the current state of affairs in the latent print community, to provide an avenue to circulate original fingerprint-related articles, and to announce important events as they happen in our field.
Breaking NEWz you can UzE...
compiled by Jon Stimac

Faster Fingerprints as Cops try Roadside Test GLASGOW EVENING TIME, UK - Nov 22, 2006 means officers won't have to take suspects to the station for fingerprint identification...

Fingerprints Lead Cops to Alleged Killer DETROIT NEWS, MI- Nov 20, 2006 ...fingerprints on a flashlight used to kill a father of two helped find his killer...

Suspect Surfaces in '03 Homicide ROCK HILL HERALD, SC - Nov 18, 2006 ...fingerprints and cooperation between federal and local police led to the arrest in Missouri...

New Fingerprint Technology IDs the Bad Guys Faster than Ever POLICE NEWS, CA - Nov 17, 2006 ...fingerprint technology has developed more in its past 15 years than it did in the first 100 years...

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Last Week's Board topics containing new posts
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Internship in Forensic Science
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Neville 21 Nov 2006 01:21 pm



Updated the Smiley Files with two new smiley's... the latent has a neat story associated with it from Michael Williams in NY:  I had a fun one the other day.  I developed a fingerprint on a paper note from a burglar.  This time was not a burglary – just a stupid criminal note after a larceny which he quoted himself as saying he would never be caught, that he is a “thief” and a “scumbag.”  I can’t wait to see the court reaction to his admissions.  I could see the smiley when developing with Ninhydrin.  When I hit on SAFIS I confirmed it was a smiley and also found he had around nine pages on his rap sheet for burglary, aggravated harassment and some violent felonies.  We are still waiting on the submitting agency to confirm he was not the victim – which is not likely.


Last week

we took a look at a recent article that is critical of latent print examination, as well as two replies to the article.

This week

we hear from Dave Charlton and Itiel Dror on psychology research involving fingerprint examination.

Forensic Expertise and Self-Trust
by David Charlton
from Forensic Update 87 - October 2006
Division of Forensic Psychology Awards

Much of the discussion within this paper is based upon my experiences as a fingerprint expert and latterly as a research student with Dr Itiel Dror at the University of Southampton. My initial concerns and research interest in my own professional methodology compelled me to conduct a literature search on psychological influences on decision-making. I contacted Dr Dror at the University of Southampton and was invited as a PhD research student to conduct and assist in various research threads associated with cognition and decision-making using fingerprint analysis as a central theme to these studies. This work has highlighted that the decision-making of fingerprint experts can be influenced by external factors such as emotional responses to evidence placed before the expert in a certain context. The notion of contextual bias within the identification sciences has now become an accepted terminology and has entered the mainstream forensic literature as a way of explaining in part some highly publicised erroneous fingerprint calls over recent years.

This brief paper outlines a few basic concepts behind my research which has recently culminated in my receiving the Division’s Junior Award.

As a nationally registered fingerprint expert working with the police service I have become increasingly uneasy with the apparent ease with which both the judiciary and the wider general public accept evidence without huge cross-examination and interrogation. Some years ago I prepared a case for a murder trial that involved the identification, compilation and presentation of literally hundreds of latent finger marks form a myriad different but associated crime scenes. Expecting many hours of court questioning by defense barristers, I prepared tirelessly for many weeks to learn my case, fully familiarise myself with the evidence and generally prepare to answer any question put before me as the expert witness in the case. I was at the same instant relieved yet horrified to spend less that four minutes under oath. Both prosecution and defense, without testing the evidence in the court, accepted my evidence in chief. This troubled me. As an expert witness my duty to the court is to inform and to educate so that jurors should make informed decisions as to guilt or innocence. Could it be that my general demeanor, my suit and tie, my qualifications, my employer and the very nature of the evidence was actually influencing the course of justice to a point where fingerprint evidence was accepted without question?

In many countries the individualisation of a single finger mark from a crime scene to a suspect can lead to the conviction of a perpetrator of a crime, and in some cases can mean long terms of incarceration and even execution. The burden and responsibility placed upon a latent print examiner is great. In the compilation of evidence and the ultimate presentation of that evidence in the courts, the fingerprint expert is a figure of some respect and authority. The judicial system places trust in the ability and competence of the expert witness. Jurors place their faith and confidence in the word and opinion of the individual presenting fingerprint evidence. To demonstrate that expert witnesses are credible they must be sure and resolute in their decision making skills, and be certain in the knowledge that what is presented as evidence is in fact the truth, the whole truth and nothing but the truth. Fingerprint experts are indoctrinated from the earliest days of training to be certain in their decisions, never waver and to understand that there is no grey area in a fingerprint comparison. The conclusion reached can only ever be individualisation, or exclusion, or that the clarity within the comparison is so poor as to make the decision inconclusive. Either way, the fingerprint expert is expected through training and experience to be able to differentiate between finger marks of varying quality thresholds. The expert is expected to reach an absolute conclusion that when explained to the court will leave the judiciary and jurors in no doubt as to the accuracy of the evidence being presented.

If we assume that the acceptance of fingerprint evidence, or any other form of forensic evidence, is based on trust by the judiciary and public in the credentials of the practitioners and scientists, then what happens to the weight of that evidence when the levels of self-trust within the individual fingerprint examiner wavers?

From my own experience it is troubling that fingerprint examiners are sometimes unable to make a decision on a particular fingerprint comparison on one particular day, only to be able to make a clear and cogent decision the very next day on the same piece of evidence. Such daily variables in ability to make a decision cannot be acceptable if it is acknowledged that fingerprint expert training, experience and adherence to strict examination protocol and procedure should negate such swings in decisiveness. If all known procedures are applied diligently it must be conceded that other factors are relevant to the decision making process.

Fingerprint expert examiners are not supposed to exhibit behavioral traits associated with uncertainty or self-doubt. It is a sign of weakness in the eyes of many within the fingerprint profession to display anything other than absolute certainty. Through objective analysis using a methodology known as ACE-V (Ashbaugh, 1999), that is to say through careful assessment, comparison and evaluation, the expert is expected to reach a conclusion as to individualisation or not, as the case may be,
with absolute certainty. These findings are then verified through repeatable procedure by fellow expert examiners, who will confirm or counter the original examiner’s decision.

As well as objectivity in the processes and procedures of fingerprint analysis, there is also an element of subjectivity in the interpretation of minutiae within the detail that constitutes friction ridge skin. This conflict between objective analysis methodology and the visual subjectivity of the examiner has not until recently been explored in the domain of forensic science. This divergence of philosophy has contributed to recent controversies within the fingerprint analysis domain. Controversy that has led to the criminal justice system, academics, the public and the media questioning the very fabric of fingerprint evidence as a reliable and trustworthy science.

The case of Shirley Mckie in Scotland has sent shock waves around the world amongst the fingerprint and wider forensic scientific community, and has indicated to an increasingly skeptical public the level of subjectivity that is applied to the science of fingerprint analysis. Shirley McKie, a police officer, was arrested for perjury after she made denials in a murder trial that she had left her thumbprint at a crime scene associated with the investigation. The normally routine act of eliminating by way of fingerprints of police and others who have legitimate access to crime scenes had resulted in a dispute of individualisation that goes on to this day. Fingerprint experts from around the world have asserted that a mistake has been made. Indeed, Shirley McKie has been acquitted of the crime. But a not insignificant number of individuals from the fingerprint community still assert that the finger mark is indeed that of the aforementioned former police officer. Michael Mansfield QC has called for a public inquiry, stating that ‘the whole so-called science of fingerprints needs to be re-examined’ (O’Neill, 2006). Academic critics of fingerprint science have also been vocal on the evidential reliability of the processes and methodology. Simon Cole, a criminologist at the University of California, has stated: ‘fingerprint matching is undoubtedly a valuable tool for catching criminals but nobody knows how often examiners make a wrong call’ (Bamber, 2005).

Dr Itiel Dror suggests, ‘the mind is not a camera. It is a dynamic machine that can distort what it sees. Perception is far from perfection’ (Dror et al., 2005). If Dror is correct in this statement, then how can a fingerprint examiner have total faith and trust in what they see? This premise may lie at the heart of the very subjectivity to which I alluded to earlier. Friction ridge skin is elastic and malleable. Deposition pressure can affect the way friction ridge skin may present itself to the examiner. Likewise, movement and slippage at the time a latent print is deposited on a surface will affect the appearance and quality of the crime scene mark. All such factors require interpretation and understanding by the examiner before a conclusion on individuality can be reached. Relative correlation between points of reference on a finger mark from a crime scene are used during the comparison process when comparing features on the crime scene mark with a known exemplar of a suspect taken under laboratory conditions. The relative configuration of such reference points is important to the identification process. Figure 1 [on the website version of the Detail] shows an example of a comparison chart using relative features in friction ridge skin from a known exemplar and an unknown source.

Ridge detail such as distance between individual features, ridge thickness and ridge counts between minutia all influence the decision of the examiner. Should the quality of a crime scene mark be very poor then it can be argued that the human eye could be fooled into seeing something within the print that is not there?

While such visual illustrations are fun to look at, they do at their core have a very serious message for fingerprint experts. Namely, that what is in the mind’s eye is not always what is actually there. This is a fundamentally dangerous phenomenon for any scientists involved in visual interpretation, whether it be fingerprint recognition, facial recognition or trying to recognise a bomb in a suitcase at an airport security lounge.

Such visual effects are in themselves enough to potentially influence the decisionmaking processes of fingerprint experts. But research has also identified another potentially dangerous influence on the expert, namely contextual top-down processing. Dror et al. (2005) suggested that emotions of individuals at the time of a fingerprint comparison could indeed influence their end decision. Dror et al. (2005)showed that
participants were affected by top-down manipulations on emotional responses engendered by disturbing crime scene imagery. Where the fingerprints to be compared were classed as difficult, or ambiguous, then the participants in the study were more likely to make affirmative judgement calls if associated within a disturbing context.

The study results, while interesting, required confirmation within the fingerprint expert domain. Since the findings mentioned above were derived using laypeople (students), it was important to confirm these findings within a real-world forensic environment.

A further investigation took place to see whether fingerprint experts could objectively focus on feature information within a fingerprint analysis without succumbing to misleading extraneous information such as context (Dror, Charlton & Peron, 2006).
Figure 2 [on the website version of the Detail]: Visual interpretation of the central figure in the chart above will depend on the visual context
placed before the examiner

Fingerprints that had previously been examined and assessed by latent print experts as a positive match were re-presented to the same experts, but within a context that the correct conclusion should be a negative match. Within the new context most experts made differing judgements to their original conclusions thus contradicting their own earlier findings. This study was repeated with a new set of fingerprint experts and produced the same end result (Dror & Charlton, 2006) – namely that contextual bias was a key driver in the decision-making process.

Findings in earlier studies have highlighted that fingerprint experts are vulnerable to contextual influences. It will be important to try to ascertain how these influences manifest themselves, how such influences might be minimised or eradicated, and what steps could be taken to enhance training, accreditation and methodology to improve the resistance of experts to such influences. To begin to understand the emotional drivers of fingerprint experts I have embarked upon qualitative studies of fingerprint experts to better understand the motivational factors that experts experience during the process of fingerprint examination. Only by isolating the core emotions and motivations and then placing those emotions within a specific context can we better understand what it is that is influencing experts at the time of decision. For example, are expert examiners more emotionally driven by serious crime like rape or murder, or are they just as likely to be motivated to examine evidence from a vehicle break in or burglary with the same set of professional values applied to each scenario?

Future research will further investigate the training of forensic experts to identify how such training might be improved through better understanding of the psychological influences on the human being. By understanding how humans and especially forensic experts visualise images we can be better placed to offer enhanced training packages for fingerprint experts to alleviate many of the potential weaknesses in the methodology of fingerprint comparison. Finally, it will be important to investigate the decision-making processes of fingerprint experts within the real-world domain where technology is playing an increasingly prominent role. It will be important to assess how new technologies are either strengthening or diluting the decision-making abilities of experts. Another key strand of investigation will be the way in which forensic evidence is both served on the court and how the public and judiciary alike receive it. For example, should fingerprint evidence be presented using word of mouth only, or do visual presentations
convey the message within the evidence more effectively?

Ditto and Lopez (1992) have shown that information consistent with a preferred conclusion is examined less critically than information that is inconsistent with a preferred conclusion. This is interesting when applied to the verification process for fingerprint matches mentioned earlier in this paper. It could be that knowledge of a positive outcome or identification of a fingerprint may influence the verifier. It could be that they would look at the detail within the fingerprint less critically on verification if they prefer to see a positive outcome – for instance, in a murder case where the conviction of the ‘bad guy’ is paramount by the public, police and wider judiciary. This merits further

Only then, as a psychologist and as a fingerprint expert can I regain my own selftrust in my abilities to accurately interpret fingerprint evidence. By conducting such research the fingerprint profession as a whole can engage the trust of the public and wider criminal justice system that fingerprint science is as reliable and methodologically sound as it can be.

David Charlton
University of Southampton
School of Psychology, University of Southampton, Southampton SO17 1BJ;


Ashbaugh, D.R. (1999). Quantitative-qualitative friction ridge analysis: An introduction to basic and advanced ridgeology. New York: CMC Press.

O’Neill, E. (2006). Mark of innocence. Guardian, 18 April, 6–9.

Bamber, R. (2005). Fingerprints fail reliability test. The Times, Public Agenda, 20 September Dror. I.E. ( 2005). Fingerprint doubt. Forensic
News, Police Professional, 3 November.

Dror, I.E., Peron, A., Hind, S. & Charlton, D. (2005). When emotions get the better of us: The effect of contextual top-down processing on matching fingerprints. Applied Cognitive Psychology, 19(6), 799–809.

Dror, I.E., Charlton, D. & Peron A. (2006). Contextual information renders experts vulnerable to making erroneous identifications. Forensic Science International, 156(1), 74–78.

Dror, I.E. & Charlton, D. (2006). Why experts make errors. Journal of Forensic Identification, 56(4), 600-616.

Ditto, P.H. & Lopez, D.F. (1992). Journal of Personality and Social Psychology, 63(4), 568–584.


Too often scientific work fails to impact the real world. Three main reasons for this dichotomy are:

■ The scientific work is too abstract, academic, and remote from the practicalities of the real world, and thus it is not applicable and able to make an impact.

■ People in the real world do not want to hear about scientific research; this may be due to the lack of respect for basic science and scientists, wanting to stay in charge and keep control over their domain and not have outsiders tell them what to do, or that they just do not like what scientific research has to say.

■ Real-world settings conduct their own research, which in practice is often too narrow, not derived from theoretical understanding and conceptual framework, is self-interested and motivated to promote specific agendas, is too close to the politics, ideology or people at the workplace and is thus influenced and biased.

This partial list illustrates the grave challenges and obstacles in bridging scientific research and the real world. In areas of forensics these issues are further exacerbated and additional issues arise (such as legal and social ramifications).

It is thus rare to see how scientific research really impacts on the world of forensics, and especially in problematic issues of human error and misidentifications of suspects.

David Charlton, this year’s recipient of the Division of Forensic Psychology’s Junior Award, is a par excellence example of achieving this highly challenging goal. He has been engaged in conducting scientific research about errors in fingerprint identification. As he is a fingerprint expert himself, this topic is highly sensitive and he has had to endure defensive and even personal responses from some of his colleagues in the fingerprint world. However, he has continued with his objective scientific research, pursuing it with personal integrity, professionalism and perseverance.

David Charlton came into the academic world through his interest in understanding the underpinning of his work in the forensic domain. His intellectual curiosity and intellect pushed him to go beyond being a practitioner. However, his academic work did not cause him to abandon the real world either. David continues to keep his feet on the ground in forensic work.

The research of David Charlton has already impacted on the work of forensic experts worldwide. There is no question that this is due to the high quality and excellent research he has conducted, but that would Junior Award: David Charlton only be enough to receive academic recognition. David’s work has gone beyond academia because of his dedication and concern about the real world of forensics.

Bridging academic research and the real world is not only important in terms of the impact and improving practical things, but because the relationship is reciprocal. The transfer of knowledge is bidirectional: not only do findings from scientific research impact the real world, but the application of the research then feeds back to the academic domain and contributes back to the scientific research. Thus, rather than a dichotomous or a one-way parasitic relationship, bridging research and the real world should be a symbiotic relationship where all sides benefit and contribute to each other.

David Charlton has built such a bridge in the fingerprint identification domain. I want to personally congratulate him on this achievement and I am sure we are going to see David continuing his productive and interesting work for many years to come.

Itiel E. Dror
University of Southampton
Forensic Update 87 – October 2006
Division of Forensic Psychology Awards

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Until next Monday morning, don't work too hard or too little.

Have a GREAT week!