Confirmation Bias

[Jackpine Radical]

6. No foolin'. Here's an intresting recent study.

The forensic confirmation bias: Problems, perspectives, and proposed solutions
Saul M. Kassin, Itiel E. Drorb, Jeff Kukuckaa

Journal of Applied Research in Memory and Cognition
Article history:
Received 28 October 2012 Received in revised form 29 December 2012 Accepted 3 January 2013

No link because it's behind a paywall, but the lead author will likely send you a copy of thw whole thing if you email him.
E-mail address: [e-mail] (S.M. Kassin).

On March 11, 2004, a coordinated series of bombs exploded in four commuter trains in Madrid. The explosions killed 191 people, wounded 1800 others, and set into motion a full-scale international investigation. On the basis of a latent fingerprint lifted from a bag containing detonating devices, the U.S. Federal Bureau of Investi- gation (FBI) positively identified Brandon Mayfield, an American Muslim from the state of Oregon. Subsequent to 9–11, Mayfield had been on an FBI watch list. Following standard protocol, a num- ber of FBI fingerprint examiners independently concluded that the fingerprint was definitely that of Mayfield. After being arrested and appearing in court, Mayfield requested to have a fingerprint examiner on the defense team examine the prints. That fingerprint examiner concurred with the judgment that the print was Mayfield’s. Soon thereafter, however, the Spanish authorities matched the prints to the real Madrid bomber, an Algerian national by the name of Ouhnane Daoud. Following an internal investigation at the FBI and a report by the Office of the Inspector General (OIG, 2006), “confirmation bias” was listed as a contributing factor to the erroneous identification. At that point, the U.S. government issued a formal apology, and paid two million dollars in compensation.

The FBI has rigorous standards of training and practice and highly competent forensic examiners. It is considered one of the best, if not the best forensic laboratories in the U.S., if not in the entire world. Thus, it was not easy to dismiss the error and claim it to be the product of mere “bad apples.” The Mayfield case (preceded by a decade in which the U.S. Supreme Court had sought to curb the introduction at trial of experts in junk science—see Daubert v. Merrell Dow Pharmaceuticals, 1993; Kumho Tire Co. v. Carmichael, 1999), along with improprieties discovered in various state laboratories, have come together to draw attention to forensic science and to the fact that is not infallible. Forensic science errors have also surfaced with alarming frequency in DNA exoneration cases and other wrongful convictions (Garrett, 2011; http://www.innocenceproject.org/fix/Crime-Lab-Oversight.php). In “The genetics of innocence,” Hampikian, West, and Akselrod (2011) found that several types of forensic science testimony had been used to wrongfully convict innocent individuals. In cases where trial transcripts or reliable forensic science data were avail- able for review, 38% contained incorrect serology testimony, which is highly regarded. In addition, 22% involved hair comparisons; 3% involved bite mark comparisons; and 2% involved fingerprint comparisons.

The National Academy of Sciences (NAS, 2009) published a scathing assessment of a broad range of forensic disciplines. Included in this critique were toolmarks and firearms; hair and fiber analysis; impression evidence; blood spatter; fibers; hand- writing; and even fingerprints—until recently considered infallible. NAS concluded that there are problems with standardization, reliability, accuracy and error, and the potential for contextual bias. Specifically, the NAS report went on to advise that: “These disci- plines need to develop rigorous protocols to guide these subjective interpretations and pursue equally rigorous research and evaluation programs. The development of such research programs can benefit significantly from other areas, notably from the large bodyof research on the evaluation of observer performance in diagnos- tic medicine and from the findings of cognitive psychology on the potential for bias and error in human observers” (p. 8).