Fingerprints, Experts and Emotions

Fingerprints
[Photo by Happy to be]
We all rely on experts to make correct and consistent decisions: from medical professionals to fingerprint experts. We'd like to think these decisions are unaffected by their often highly charged emotional contexts, but is that really the case?

On the 11 March 2004 thirteen bombs were loaded onto commuter trains at Alcala de Henares station, 40km outside Madrid. Not long after, ten of them exploded killing 191 people and wounding more than 1,700. Using a fingerprint found on a plastic bag filled with detonators, the FBI, with automated computer matching and experienced experts, obtained and confirmed a positive identification with a US citizen, Brandon Mayfield. Mayfield, a recent convert to Islam, appeared to fit the bill perfectly and he was immediately arrested and imprisoned.

Nevertheless, two weeks later, Mayfield was released after Spanish police announced they had caught the real owner of the fingerprint. Mayfield was completely innocent, having simply been the victim of two misfortunes: firstly to have a fingerprint similar to the bomber and secondly to already be in the US fingerprint database (currently totalling around 10 million entries). So, is this an isolated case, or are there systematic problems in the way fingerprint experts work? Dr Itiel Dror, provides challenging evidence of systematic problems.

Initially, Dror, Peron, Hind & Charlton (2005) examined contextual effects in a student population. It was found that participants cued with emotionally charged contextual information, such as gruesome crime scene photos, were more likely to indicate a match between ambiguous fingerprints than uncued control participants.

But, more impressively, using a within-subjects design, Dror & Charlton (2006) actually re-presented experienced fingerprint experts with cases in which, five years previously, they had confirmed positive matches. This was carried out covertly so the experts themselves were in their normal work environment, and were unaware they were examining prints they had previously analysed. Contextual information was then provided to the experts in order to attempt to replicate the findings of the earlier study in a naturalistic setting. In an admittedly small sample size (n=6), two-thirds of the experts made decisions inconsistent with their own previous judgments.

So, what's going on here, is fingerprinting fundamentally flawed? According to Dr Dror: No. In this BBC Newsnight interview, Dr Dror points out that while fingerprint evidence can sometimes be criticised, it is significantly more reliable than eyewitness testimony, which can be notoriously shaky. It is certainly not the case that fingerprinting is a fundamentally flawed process. Instead fingerprint agencies around the world should take into account new findings from cognitive science in the recruitment, training and procedures of experts.

At present many agencies give fingerprint experts contextual information about the crime, which may, clearly, bias their decisions in marginal cases. One simple recommendation would be to just provide experts with the fingerprints and no other contextual information.

Perhaps if the FBI fingerprint experts had been unaware the print they were attempting to match was allegedly one of the Madrid bombers, they wouldn't have pronounced Brandon Mayfield a perfect match. As a result, major embarrassment and law suits would have been avoided.

Of course, as a result of this case and others like it blame has been apportioned onto individuals, where in fact it lies diffuse throughout the system. A system that, if these findings are further replicated, clearly needs a helping hand from cognitive psychology.

Acknowledgement: This post is based on a presentation given by Dr Itiel Dror on fingerprint identification at a UCL Departmental seminar. My thanks to Dr Dror for an enlightening talk.

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. [Abstract | PDF]

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

Barely intelligible report from the FBI on the 'Erroneous Fingerprint Individualization' which apparently was their first mistake. Ever.

J. G. Ballard, The Psychologist

J. G. Ballard
[Photo by Catfunt]
The beauty of a novel is it can transport you inside someone else's mind. Even the dreariest hack has to be on nodding terms with human psychology in order to pump out a half-decent airport novel. Few novelists, though, worship at psychology's altar with the vehemence of J. G. Ballard. And few others can, in my view, match Ballard for his uniquely exhilarating and often equally disturbing results. Frequently referred to as the 'Seer of Shepperton' Ballard is a keen observer of all that makes us human, using his novels almost as laboratories in which he can pose questions about humanity.

What does it really mean to live in a modern consumer society, a position so familiar we barely notice its presence? What does it mean that everyone is trying to sell you something? What does it mean to live in a morally and aesthetically sanitised environment? Why do we behave the way we do? What does it mean to be human now, and what will it mean in the future? These are just a few of the questions Ballard's work addresses. Take two of these: violence and our motivations.

Violence has always been an important theme in Ballard's work. What is our fascination with violence? A fascination so potent, it is both denied and tacitly accepted at the same time. In 'Super-Cannes' Ballard foresees a time when late capitalist societies will begin tapping this vein of psychopathy in human nature in immediate ways. In the imagined French town of Super-Cannes, violence is marketed to the willing consumer in a novel way, not just through the television and cinema, but in real life, as a form of therapy for the increasing boredom of everyday experience.

For motivation take 'End-Game', written by Ballard in 1963, also collected in 'The Complete Short Stories'. It tells the story of a man, living in some strange alternate reality, who is imprisoned with his executioner. There, in a grey villa, a typically featureless Ballardian space, he awaits his execution for some obscure and unmentioned deed. First we see the convicted man try to extract the exact date of his execution from his executioner, then begin to question his own guilt.

Within the first 500 words, the prose is already redolent of psychological and psychoanalytic literature with mention of introversion, extraversion, transference and sublimation. But really the story is about how our most solid perceptions of the world and ourselves can be changed if the motivation is strong enough. If, for example, your life depends on it. And this is precisely what happens to the protagonist as he moves from being convinced of his own guilt to being convinced of his own innocence. Ironically, in the story, it is this shift which dictates the moment of his execution.

It comes as no surprise, then, that Ballard is an avid reader of both psychiatric and medical journals. Indeed, while Ballard's stories often contain psychiatrists and psychologists, his own writing is ripe for analysis itself, a task to which many have warmed.

If I had to suggest one feature of Ballard's prose I find particularly attractive, it is the mutability of both his characters and the societies they inhabit. We tend to think of ourselves, others, society in general, as something monolithic or at least only undergoing very gradual change. Reading Ballard is something akin to making counter-intuitive discoveries in psychology; it's about discovering that the rules people unconsciously follow don't always make sense.

Ballard goes further, by highlighting the possible worlds of human behaviour - for example people gaining sexual excitement from car crashes - while still adhering to an internal logic, he casts light on our current world of human behaviour. Like all the best science fiction, it's not about the future, it's about the present.

'Ballardian' is a fabulous site with interviews, reviews and features.
Profile of Ballard (The Independent)
Review of his new novel (The Independent) 'Kingdom Come'
Wikipedia has a short biography
Spike Magazine article focussing on Super-Cannes

PsyBlog Evolves: Status Report

Evolves
[Photo by WASABldesign]
PsyBlog has evolved considerably over the last year and I wanted to highlight a few of these changes and get some feedback from you, dear reader. Perhaps regulars will already be aware of the changes, perhaps not. I'm not even sure I've been aware of many of the changes myself! To me, the shifts in content, as well as an ongoing redesign project, have happened at an almost imperceptible rate. But, I can deny it no longer, the PsyBlog baby has shot up into a spotty adolescent. As part of taking stock, I'd like to run a few things by you. So, all constructive criticism is welcome.

Looking back at posts from a couple of years ago, I notice these tended to focus on linking to items from news articles, and sometimes providing a little critical commentary. Nowadays the focus is much more on summarising and commenting on current academic journal articles. Even now I'm noticing a shift away from summarising and towards commenting and integrating. I'm assuming you are happy to scan the abstract. If that's not the case, please let me know!

I've introduced the 'Stream', the column to the right of this, to allow me to link directly to stories on other blogs and snippets that I've picked up. The Stream is really a record of the things I've read and I think are worthy of passing on. With the increasing numbers of psychology bloggers out there, this is continually growing.

As a result of starting the Stream, there are now two 'site feeds' (RSS feeds) for this blog, which you can see linked up at the top of the left-hand column. Follow the 'What is RSS?' link to find out more about 'subscribing' to these feeds. If you're not already using some kind of news reader then I'd strongly advise you to start as it makes keeping up with the blogs in which you're interested much easier.

Unfortunately a natural result of these shifts, as well as my limited time, is that the post frequency has gone down. Hopefully, though, the quality of both the content and writing is going up - that's my overall aim for the site. For PsyBlog I believe less frequent but slightly longer and more considered posts better serve both you and me.

One thing that hasn't changed much over the last couple of years is the wide variety of topics PsyBlog has covered. Despite my recent obsession with unity in psychology, it seems likely the variety will continue. I like to post about things I'm interested in, and, naturally, I'm interested in a lot of things!

Finally I'd like to say thanks to everyone for reading, and encourage you to post comments on the stories as well as email me. So, if you've got any points you'd like to make about any aspect of PsyBlog (as long as it's not typo related!) then please do leave a comment below.

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