Category Archives: Forensic science

Science and Law: Open access section in the June issue of Isis

justiceisblindThe June 07 issue of the History of Science Society journal Isis (vol 98 no 2) has an open-access focus section about Science and Law.

The Isis press release (11 July) explains that the collection of papers:

…draws together scholarship about the intersections of science and law, exploring what happens when science enters the courtroom or the course of scientific inquiry is determined by legal outcomes… “Evolving legal systems have consistently been forced to draw on (or defensibly away from) scientific knowledge, scientific methods, and scientific experts in the pursuit of truth and justice,” writes D. Graham Burnett … in his introduction to the Isis collection. “At the same time, courts . . . have to a significant extent shaped both the theories and the practices of knowledge production central to the emergence of modern science.”

The article of most interest to forensic psychologists is probably Alison Winter’s paper A Forensics of the Mind, which

…discusses the yoked history of witnessing in science and the law and examines the history of attempts, over the past century, to use science to improve the surety of witness testimony… It concludes that a key feature of modern disputes over the legal relevance of psychological techniques is not the quality or character of the expertise being offered to the court but, rather, the question of whether expertise is needed at all and under what circumstances it should impinge on the jury’s decision making.


Photo credit: RaeA, Creative Commons License

Does the ‘CSI Effect’ Exist?

CSIManitobaThe ‘CSI effect’ apparently occurs when jurors, witnesses and others have raised expectations about the amount and quality of forensic evidence available during trials, as a result of watching CSI, Law and Order and similar crime entertainment shows. The term has also been used to refer to the way in which criminals apparently change their modus operandi to take account of forensic science advances.

According to Donald Shelton and colleagues from Michigan, the ‘CSI effect’ might be a misnomer. The researchers surveyed more than 1000 real jurors about their expectations of forensic evidence, and about their TV habits.

The authors explain in their abstract:

… While the study did find significant expectations and demands for scientific evidence, there was little or no indication of a link between those preconceptions and watching particular television shows. The authors suggest that to the extent that jurors have significant expectations and demands for scientific evidence, it may have more to do with a broader “tech effect” in our popular culture rather than any particular “CSI effect.” At the same time, this article contends that any such increased expectations and demands are legitimate and constitutionally based reflections in jurors of changes in our popular culture, and that the criminal justice system must adapt to accommodate jurors’ expectations and demands for scientific evidence.


Hat tip to the Freakonomics blog (29 May).

Photo credit: Samboomba, Creative Commons License

Articles of forensic interest in June’s Monitor

jun07thumbThis month’s APA Monitor on Psychology magazine (Vol 38, No. 6, June 2007) includes several stories of interest in a forensic context.

The cover story is a triple-bill of short articles on psychology in the courtroom:

    • Order in the court: The best way to educate juries on the pitfalls of eyewitness evidence? Teach judges, say psychologists.
    • To ask or not to ask: The practice of allowing juror questions gains momentum.
    • The problem with DNA: Forensic evidence increasingly includes genetic fingerprinting, but researchers worry that juries put too much stock in the results.

Also in this issue, an articles on:

All this and reminiscence by rats

Study questions reliability of fingerprint evidence

header2We featured news of research by Dr Itiel Dror from Southampton University (UK) last year on Psychology and Crime News. Dr Dror presented his findings at the recent British Psychological Society annual conference, resulting in a couple of news stories about the research. This from the Guardian (23 March):

[…In] 2004 Brandon Mayfield was wrongly linked to the Madrid train bombings by FBI fingerprint experts. Fingerprint examiners say these are isolated mistakes and claim that the science of fingerprint matching is sound.

[…Dror] presented six fingerprint experts from various countries including the UK, the US and Australia with eight marks from crime scenes (called latent prints) and eight inked marks from suspects. The experts, who had 35 years experience between them, had all given judgments on the pairs of prints in previous court cases – four as matches and four as exclusions.

But Professor Dror engineered the experiment so that none of them knew they were participating in a study, something that he says makes the study much more powerful. “If people know they are studying them they behave differently, especially if you are studying errors,” he said.

Of the 48 tests, the experts changed their decision in six cases and only two of the experts were consistent with their previous decision in all of their eight cases. They were more likely to change their decision if given contextual information, such as “the suspect has confessed”, that conflicted with their previous judgment.


How do forensic scientists learn to become competent in casework reporting in practice?

forensicbookFrom the latest issue of Forensic Science International (vol 167, issues 2-3, April 2007), some new research on how forensic scientists develop expertise. From the abstract:

[…] We show that tacit knowledge is an integral part of the activities of expert forensic science practitioners who continually add to their knowledge repertoire by engaging other scientists through communities of practice. We wish to shed fresh light on the gaining of tacit knowledge by forensic scientists during their apprentice formative years, termed as legitimate peripheral participation. In quantifying tacit knowledge exchanges, we use social network analysis, a methodology for the analysis of social structures, to map relational knowledge flows between forensic scientists within communities of practice at the Forensic Science Laboratory, Ireland. […]


Photo credit: Tojosan, Creative Commons License

Cognitive science and the law

The always-interesting Trends in Cognitive Sciences carries a review article this month on Cognitive science and the law by Thomas Busey and Geoffrey Loftus. From the abstract:

Numerous innocent people have been sent to jail based directly or indirectly on normal, but flawed, human perception, memory and decision making. Current cognitive-science research addresses the issues that are directly relevant to the connection between normal cognitive functioning and such judicial errors, and suggests means by which the false-conviction rate could be reduced. Here, we illustrate how this can be achieved by reviewing recent work in two related areas: eyewitness testimony and fingerprint analysis. We articulate problems in these areas with reference to specific legal cases and demonstrate how recent findings can be used to address them. We also discuss how researchers can translate their conclusions into language and ideas that can influence and improve the legal system.


Talking security cameras has an article (22 Dec) from Nick Allen on crime prevention in the UK, and the implications for privacy, in George Orwell Was Right: Spy Cameras See Britons’ Every Move:

It’s Saturday night in Middlesbrough, England, and drunken university students are celebrating the start of the school year, known as Freshers’ Week.

One picks up a traffic cone and runs down the street. Suddenly, a disembodied voice booms out from above: “You in the black jacket! Yes, you! Put it back!” The confused student obeys as his friends look bewildered.

“People are shocked when they hear the cameras talk, but when they see everyone else looking at them, they feel a twinge of conscience and comply,” said Mike Clark, a spokesman for Middlesbrough Council who recounted the incident. The city has placed speakers in its cameras, allowing operators to chastise miscreants who drop coffee cups, ride bicycles too fast or fight outside bars.

Hat tip to Slashdot!

Is CSI to blame for a drop in solved rape cases?

Newsday (19 Sept) reports that:

The percentage of rape cases going unsolved nationwide is increasing, according to an FBI crime report released yesterday, and bleach, condoms and gloves are among the tools used by rapists in recent years to escape punishment.

[…] “I think criminals are becoming more cognizant of technological advances,” says Kenneth Rau, Suffolk chief of detectives, who adds that some criminals “are reacting to shows.”

“They’re making their victims shower or bathe,” adds former FBI profiler Clint Van Zandt, who cites crime shows as one possible reason for this trend. “It gives the criminal with any common sense pause to think, ‘Hey, there’s a way to cover my trail or conceal my DNA.’ “

Report finds fingerprint experts swayed by background information

An interesting report in The Scotsman (31 July) featuring research carried out by Dr Itiel Dror, a psychologist at the University of Southampton (UK), on cognitive bias in fingerprint experts:

Fresh doubts over the accuracy of fingerprint evidence in courts has been raised by new research showing experts can be easily swayed in their judgements by “background” information. The study found that experts can unwittingly “see what they want to see” when looking at scene-of-crime prints, resulting in wrong decisions which potentially could lead to miscarriages of justice.

[…] In Dr Dror’s experiment, six fingerprint experts from around the world were given eight “latent” crime-scene prints which they were asked to compare with sets of elimination prints. The experts were unaware that they had previously examined the latent prints. Before viewing four sets of prints, each expert was given false information – it was either suggested to them that the prints were from the criminal or were eliminated from the inquiry when the opposite was true. This “biasing context” led four of the six anonymous experts to change their minds and come to a different conclusion. One expert changed his mind three times.

The study is rather small n, which I suppose one could quibble about. But, to me, the more interesting aspect of this news item is how a committee of Scottish members of parliament has picked up on the research and believes it to be relevant to their policy making:

Members of the Scottish Parliament’s justice committee yesterday said the research has major implications for their inquiry into the Scottish Criminal Records Office […] Bruce McPhee MSP, who sits on the committee, said the research provided scientific proof for the growing belief that fingerprint experts are subject to unacceptable levels of influence. He added: “I think [the study] has major implications for the Scottish fingerprint service. This is very useful information. Dr Itiel Dror should be encouraged to submit his findings to the committee.”

Dr Dror’s report is available as a PDF download here. His university webpage indicates that he has published several articles on this topic.


  • I.E. Dror and D. Charlton (2006). Why Experts Make Errors. Journal of Forensic Identification 56 (4), 600-616.

Using DNA to predict the race of an unknown offender

Picking up on an article by Sheri Fink in the latest issue Discover Magazine (Vol 27, 7, July 06) which raises “questions about the forensic infallibility of DNA”, Rebecca Skloot writes (Culture Dish, 13 July) on DNA and racial profiling:

A while ago, I posted about my wariness of using DNA testing for genealogy research –– specifically my frustration with the fact that these tests are over-hyped by the media and sold as being able to say things like, you are or aren’t African-American, which simply isn’t scientifically possible at this point.

[…But] Turns out, police departments are now using the exact tests (and companies) I wrote about in my earlier post and my Popular Science article to try and identify the race of potential suspects based on DNA samples.

For Skloot, the key issue is the dataset that the analysis is based on, and whether those who supplied DNA for such a dataset gave informed consent to it being used to help determine the race of an offender:

When they send out those profiles of people with genetic makeups similar to the criminals, they’’re using information they’ve collected in a database from testing many people. I wonder if this includes the DNAPrint database, which houses genetic information from thousands of people who submitted their samples for genealogy testing.