In the aftermath of the Madrid train bombings on March 11th,
2004, the FBI quickly joined the Spanish police force to mount an international
investigation. Within days of the attacks, in which 191 people were killed and
2,000 more injured, Bureau investigators found an abandoned van near the crime
scene, containing a bag filled with bomb-making equipment and covered in
FBI fingerprint experts digitized the prints, ran them
through a computerized search of their database and matched them to those of 15
people, including lawyer Brandon Mayfield, a Muslim convert who lived in
Portland, Oregon, with his Egyptian-born wife. Mayfield was promptly arrested
and imprisoned, only to be released 2 weeks later, after Spanish police said
they had identified an Algerian named Daoud Ouhnane as the mastermind of the
Mayfield's is far from being an isolated case: Since 1989,
nonprofit legal organization The Innocence Project has documented the cases of 347 people who were wrongly convicted of
crimes and then later exonerated (usually on the basis of DNA evidence), often
after spending long periods of time behind bars.
In the David Kopf Lecture on Neuroethics at the 46th
annual meeting of the Society for Neuroscience in San Diego in
Albright of the Salk Institute for Biological Sciences argued
that it is time to reform forensic science to ensure that such miscarriages of
justice do not continue to occur. [See: Will Neuroscience and Law Collide?]
Tools aren’t the
science gives us a feeling that we have a leg up on the bad guys, and that with
sophisticated tools, we'll be able to figure out who the culprit is in any
given situation,” said Albright. “But this idea stands in sharp contrast to a
number of very notable and egregious failures in recent years.”
currently lacks rigor, he says, and is quite often poorly rooted in science,
being plagued by bad data analysis practices and poor use of statistics. What's
more, many forensic scientists seem to have little understanding of how human
vision and memory work.
described fingerprinting and eyewitness identification of suspects as processes
on which the criminal justice system is heavily based but which are prone to cognitive
biases that can influence decision-making in ways that can pervert the
course of justice.
experts make mistakes because of three types of cognitive bias, Albright said.
One is uncertainty, which arises because of the way the brain's visual system
works. The brain interprets visual stimuli on the basis of very limited
information; it “fills in the gaps” to predict what we are seeing. This
involves drawing on our past experiences, bringing another bias into play.
is plagued by noise from many natural sources, such as the poor optics of the
eye, dim lighting, and distracting features in the scene, so we're faced with a
lot of uncertainty about what we're actually looking at,” said Albright. “Our
biases pull everything together and help us to fill in the blanks about what is
likely to be out there given our prior experience of the world.”
biases can cause us to perceive meaningful patterns that aren't there and,
sometimes, to see things that actually do not exist. A good example of this is
pareidolia, or our
propensity to see non-existent faces in objects.
was because of such biases that Brandon Mayfield was misidentified as the
perpetrator of the Madrid train bombings. Mayfield’s print was in the FBI’s
database because of his military service, and was not an identical match to the
prints left on the bag of detonators. Even so, as a recent Department of Justice
review revealed, the FBI used expanded surveillance powers under the
Patriot Act to collect information about him and monitor his activities. Some
of his biographical information—such as his legal representation of an alleged
terrorist—confirmed the FBI’s biases and convinced them that he was guilty.
minimize these biases, fingerprint experts should analyse prints without having
knowledge of the case, Albright said.
Seeing is believing?
work of psychologist Elizabeth Loftus showed, eyewitness testimonies are
also subject to bias and memory errors. In a classic 1974 study,
Loftus showed film footage of car accidents to 150 undergraduate volunteers and
then asked them questions about the events that they had seen in the films,
including one about how fast the cars were going. She found that those asked “About
how fast were the cars going when they smashed
into each other?” gave consistently higher estimates than those asked the same
question using the verbs collided, bumped, or contacted instead of smashed.
recollections of events are not perfectly accurate; furthermore, memories can
be influenced significantly by the way questions are asked under
though our memories can be so easily contaminated, we tend to have a huge sense
of confidence in how accurate they are. Every time we recollect a memory, we
introduce new errors, according to our expectations and biases, and store this
altered memory. Even as this process corrupts our memories, our confidence in
them increases. [See examples in Brain Science and the Law]
courts of law place great emphasis on eyewitness testimonies and suspect
identification: About three-quarters of the 347 exonerations documented by The
Innocence Project involved convictions based largely on the accounts of
the goal is truth, then misinformed biases and over-confidence are the hidden
enemies,” said Albright. “As the old saying goes, seeing is believing. That may
be true some of the time, but neither seeing nor believing is equivalent to the
adds that the procedure for creating the photo arrays shown to eyewitnesses to
identify suspects can be inherently biased. The choice of non-suspect photos can
influence the outcome of the process, for example when none of them resemble
the description of the perpetrator, making the suspect seem more conspicuous.
is developing a less-biased approach of creating photo line-ups, so that at
least some of the fillers resemble the description of the perpetrator to a
greater or lesser extent. He recently co-chaired a National Academy of Science
committee that published a
report outlining recommendations on how to improve the accuracy of
a society we're very averse to sending innocent people to jail, so this has
become a high priority that the public is very concerned about,” said Albright.
“There is an unprecedented opportunity for science to intervene and correct