Picture tomorrow鈥檚 detective, armed with his arsenal of hi-tech gadgets:
instant DNA analysers on a chip, instantly scannable molecular and fingerprint
databases of entire countries, implants that pinpoint a convicted felon.
As scientists toil to bring this vision closer, cynics might wonder when
research will be widely applied to a somewhat low-tech but equally crucial
matter: interviewing witnesses to crimes. Accurate and complete witness
testimony is the number one factor in the solving of crimes, say criminologists.
And police officers can spend up to 80 per cent of their time talking to
witnesses. Yet as recently as the 1980s, surveys showed that only 2 per cent of
officers in the US received interview training.
Ronald Fisher, a psychologist at Florida International University in Miami,
and fellow psychologist Edward Geiselman of the University of California, Los
Angeles, have been in the vanguard of efforts to change that. More than a decade
ago, they set out to turn scholarly research into what best jogs human memory
into something eminently practical鈥攁n interviewing strategy based on as
much lab-based science as they could muster. They christened it the 鈥渃ognitive
interview鈥� and have been spreading the word ever since.
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In the US, Geiselman and Fisher have conducted more than 100 courses in the
method down the decade, mostly to law enforcement trainers. And in Britain
today, nearly every policeman is trained in the rudiments of the cognitive
interview.
FALSE LEADS
So far so good. The trouble is that the police鈥檚 conversion to the ways of
psychology is far from complete. Even now the cognitive interview is only
patchily used in the US, and British police officers often don鈥檛 apply what they
have been taught. To compound matters, some psychologists have recently been
voicing reservations about the method. They worry that it might produce false
leads or witnesses who feel overly confident about the accuracy of their
recollections.
So what鈥檚 the fuss about? At Geiselman and Fisher鈥檚 courses, detectives learn
that 鈥渟tandard鈥� interviewing techniques, which officers seem to adopt
intuitively, have many pitfalls. Interviews might start with the injunction to
鈥渢ell me in your own words鈥�. 鈥淏ut quite often the witness will get out less than
a sentence before the officer interrupts and starts guiding the
interview鈥攁nd that鈥檚 bad,鈥� says Geiselman. Too often, questions are
focused on little pieces of information the detective wants to know, such as
鈥淗ow much did he weigh?鈥�, 鈥淒id he have a beard?鈥�. This way you鈥檇 never find out
if he had a wooden leg unless you asked.
The cognitive interview doesn鈥檛 just avoid such traps, it also consists of
ploys designed to jog the memory of a witness. Item number one: recreate,
somehow, the 鈥渟cene of the crime鈥� in the witness鈥檚 head. Witnesses are asked to
close their eyes and imagine where they were at the time, what they were
thinking, and what they were feeling. They鈥檙e also told to disclose any detail
they recall, even if it seems irrelevant. Irrelevant details could well trigger
relevant ones in their minds.
SCUBA DIVERS
The approach is based on the ideas of Endel Tulving, of the University of
Toronto. Memories, said Tulving, are coded into our heads in very specific,
personal ways, depending on our outlook at the time and what we paid attention
to. It鈥檚 an elaboration of the Proustian notion. Which one of us hasn鈥檛 suddenly
been transported back to a long-forgotten event by a certain smell, taste, or
sound? And to retrieve such memories, one or more of the cues we used to code
the event at the time must be present again.
Such 鈥渃ontext reinstatement鈥�, as it鈥檚 technically known, has certainly jogged
the memories of many a human guinea pig. In one study, a group of scuba divers
was asked to learn a set of words under water, while the other group learnt them
on land. Those who were allowed to recall the words in the environment in which
they had memorised them remembered 46 per cent more words than those who were
made to recall them in the unfamiliar environment. In other studies, people
asked to learn lists of words while drunk or high on marijuana displayed sharper
recall later when they were given the intoxicant.
Of course, in real life there鈥檚 no easy way to predict what cue will jog a
person鈥檚 memory. Thus, item two of the cognitive interview has the witness
recount the robbery or murder in a variety of ways in the hope that each version
would yield some extra information. One time, the tale would be told in
chronological order, another time in reverse order. And a third time, from the
perspective of someone else.
This second approach does have research data backing it up. One university
study had people recall the details of a house from a story they鈥檇 been read
from the point of view of a home-buyer. Additional facts, such as the presence
of jewels and a colour TV, came to light when the subjects were asked to recall
again, this time from the viewpoint of a burglar.
And even if a witness can鈥檛 for the life of them remember a number plate, or
some other detail, they should be encouraged to tell any fragment that they do
know. Even when a name, or a number, is beyond recall, certain details remain in
our heads. In one study, undergraduates viewing picture slides were 22 per cent
more likely to recall a number plate correctly when they went through a
cognitive interview holding a 鈥渇ake鈥� number plate into which they could snap
letters and numbers, than if they went through a standard police interview. Even
when letters were wrongly identified, the correct letter often turned out to be
next to it in the alphabet. Even partial information, points out Geiselman, will
greatly cut down on the possible cars involved in that drive-by shooting.
Another big problem for interviewers is that it鈥檚 possible for people to end
up recalling with conviction events that never happened. According to its fans,
the cognitive interview helps here as well, by discouraging officers from asking
questions such as 鈥淵ou did see him, didn鈥檛 you?鈥�.
All this theory is very nice. But how does the cognitive interview actually
measure up from an information-gathering point of view? Guenter Koenkhen, a
psychologist at the University of Kiel in Germany, has completed a careful
analysis of 42 university studies of the technique. Overall, he found, the
approach gleaned 41 per cent more pieces of information than more traditional
interviewing methods. In some studies, twice as many details were generated. 鈥淢y
feeling about the technique is very positive,鈥� he concludes.
Better still, the error rate is no worse than expected: 15 per cent of all
information, be the interview traditional or cognitive, turns out to be false,
says Koenkhen.
Even so, these are only lab studies. Many of them involve undergraduates
sitting in a room watching a video and coming back a few days later to be
cognitively (or non-cognitively) grilled. It鈥檚 a far cry from being caught up in
a crime, where things happen lightning-fast and emotions are running high or
just plain out of control. Will such traumatic circumstances help, or hinder, a
person鈥檚 memory?
On the one hand, memory researchers Larry Cahill and Jim McGaugh at the
University of California, Irvine, have shown that people are more likely to
remember details of stories and colour slides depicting gruesome things such as
bloody car crashes than to remember stories and slides with neutral subject
matter.
On the other hand, there鈥檚 the phenomenon known as 鈥渨eapon focus鈥�. Often, a
crime victim will be so preoccupied by the gun poking in his or her face that he
or she is hard pressed to remember much else.
Because of this complexity, some teams have sought to test the cognitive
interview out in the field. Once in London, and once in Miami, researchers have
trained up detectives, followed them around and then compared cognitive
interviewing against more traditional police practice. In both cases the
cognitive interview came up trumps.
HYPNOSIS CHALLENGE
In the Miami study, for instance, police trained in the cognitive interview
gleaned 63 per cent more pieces of information than did those who were not
trained in the technique. 鈥淎nd from what we could gather from corroboration,
such as suspects confessing, or the testimony of other witnesses, over 90
per cent of the details were accurate,鈥� says Fisher, who conducted the Miami
study with Geiselman.
So what about the down side? Obviously, if you need to gather information
quickly at, say, a crime scene, then it鈥檚 not the method of choice because it
takes time. More seriously, the cognitive interview was challenged in 1995 in
the California courts, after a defence lawyer argued鈥攗nsuccessfully in the
end鈥攖hat being directed to close one鈥檚 eyes and visualise events was
tantamount to hypnosis. Hypnotising witnesses isn鈥檛 allowed in California and
other states, and is banned in Britain.
Critics also worry that if witnesses know they鈥檝e been questioned using a
new, scientifically-based interviewing technique, they might appear overly sure
of their facts in front of juries, which could lead to miscarriages of justice.
But in a recent study, Fisher and his colleagues showed that mock juries found
witnesses who had been cognitively interviewed no more persuasive than witnesses
who hadn鈥檛.
Still, concerns remain. 鈥淚 do worry about one part of the technique,鈥� says
pioneering memory researcher Elizabeth Loftus of the University of Washington in
Seattle. 鈥淭he part where you鈥檙e instructed to say anything that comes into your
mind. I wonder if it might be encouraging guessing.鈥�
Psychologist Amina Memon of the University of Southampton is another who is
worried about errors. True, says Memon, the error rate is no worse than
expected鈥攂ut the fact is that the absolute number of errors is greater.
鈥淥ne piece of incorrect information could really lead investigators up the wrong
path,鈥� she says. Fisher, Geiselman and Koehnken don鈥檛 buy this argument. 鈥淭o
take it to a ridiculous extreme, you could argue that the only way to get no
errors is not to interview the witness to begin with,鈥� Geiselman says.
None of this would be an issue if the accuracy rate was better than that for
traditional interviews, rather than merely equivalent. Is this achievable?
Psychologists are working hard to find out, testing each feature of the method
to see which parts generate new facts, and which new errors. If the two aren鈥檛
the same, the error-generating parts could be removed.
The cognitive interview is even being adapted for studies of food poisoning
outbreaks and studies of risk factors for disease. The idea is to give
epidemiologists tools for jogging people鈥檚 memories about their diet and
exercise habits down the years. 鈥淭he cognitive interview should work for most
kinds of autobiographical experiences,鈥� says Fisher.
While the psychologists work at writing papers and police work at catching
criminals, maybe we can all make use of these cognitive techniques. We can cast
our minds back to what was running through our heads when we left the car in
that car park. Or where we were when we swotted for that algebra test we鈥檙e now
taking.
鈥淚 suppose I could go into business鈥攜ou know, `Have you misplaced your
glasses recently?鈥�,鈥� says Fisher, 鈥渂ut it鈥檚 hard to make a living at that.鈥�