Toward a Psychology of Forensics

American lawyers like to ponder the reason for the extraordinarily high conviction rates in Japanese courts, which exceed 99 percent. Let us assume that it is probably not attributable to the unerring skill of Japanese prosecutors. It may be due to a policy of bringing to trial only those cases that are sure to win conviction. But it is also suspected, though not substantiated, that there exists an overwhelming pro-prosecutorial bias, perhaps related to the concern about “saving face.” Better to send an innocent person to prison for a few years than to embarrass the prosecutors.

Whatever the explanation, American law professors no doubt enjoy the invidious comparison to our system, where conviction rates are more credible. For example, in 2012, the U.S. Department of Justice reported a 93 percent conviction rate. In state courts, the rate varies, from approximately 84 percent in Texas to 72 percent in New York and 59 percent in Florida.

But even these rates may have to be revised downward in light of the shocking confession from the Federal Bureau of Investigation that much of its forensic wizardry has been a sham that has led to questionable convictions in hundreds of trials.

The Justice Department and FBI officially acknowledged at the end of last week that nearly every examiner in an elite FBI forensic unit gave flawed testimony in almost all trials in which they offered evidence against criminal defendants over more than a two-decade period before 2000.

The FBI’s use of microscopic hair analysis to incriminate defendants was “a complete disaster” according to Peter Neufeld, co-founder of the Innocence Project. The vaunted hair comparison unit was found to have overstated forensic matches that favored prosecutors in more than 95 percent of the 268 trials reviewed so far, according to the National Association of Criminal Defense Lawyers (NACDL) and the Innocence Project. In 32 of those cases, defendants were sentenced to death. Of those, 14 have been executed or died in prison.

The FBI errors do not necessarily exculpate the defendants, since other evidence may have been sufficient to establish guilt. But the admission has triggered a review of cases involving the now-tainted FBI forensics in states all over the country.

Few, if any, of us will ever sit on a jury where the fate of an accused person depends literally on a hair’s breadth. But we do sit in judgment as citizens and voters on myriad issues where technical expertise is essential.

For the average person — including the average senator or congressman — rocket science really is rocket science, whose equations are beyond his grasp. In order to determine whether an air defense system will work — or is worth the billions the Pentagon is asking for it — we must rely on the evaluations of actual rocket scientists.

It is much the same in medicine. The layman cannot make his own diagnosis, but must trust the x-ray and lab test readings of skilled professionals. A second opinion, if in conflict with the first, is not necessarily the right one, and may only necessitate a third opinion, for the sake of obtaining a majority. The procedure may be democratic, but it guarantees no happy endings.

Whatever our prejudices about environmental issues, again, special knowledge comes into play. Whether it concerns the parts per billion of toxins in the drinking water or the ultimate imponderables of global warming, we must rely on a specially-trained somebody to give us the numbers to argue over.

We can’t keep criminological techniques out of the courts, nor should we want to. The misrepresentation of evidence by the FBI does not invalidate microscopic hair analysis, any more than it means fingerprinting is a hoax.

However, a healthy downgrading of the FBI’s inflated reputation will certainly follow these revelations. Prosecutors, judges and juries will all have to treat the bureau’s expert scientific opinions with much more skepticism than in the past. They must bear in mind that there are subtleties to forensic science that can elude even the best-trained and most honest practitioners — just as doctors, physicists and climatologists are susceptible to error.

But that doesn’t mean there is no psychology of error. What motivated the FBI agents to so skew the evidence, perhaps even without realizing it? Pro-prosecutorial bias? Professional arrogance? Some hidden flaw in method? We don’t know, any more than we know the secret behind the 99 percent Japanese conviction rate.

Perhaps a cue can be taken from the field of medicine, where progress has been made in combating error. In some hospitals, the introduction of a simple pre-surgery checklist has helped to offset the fallibility of the surgeon and his team.

In recent years, doctors have surrendered much of the notorious arrogance that used to come with an MD degree. They have learned to recognize their own fallibility and to accept a second opinion. Some doctors even encourage it.

The FBI’s admission of error in these cases is a step in the right direction, for the admission of mistakes that have been made can generate that awareness of fallibility that can prevent mistakes in the future.

That much is certain, beyond the shadow of a doubt.