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In the contest between heart and head, clinicians often listen to whispers from their experience and vote with their hearts. They prefer not to let cold calculations decide the futures of warm human beings. Feelings trump formulas.

when pitting an interviewer’s predictions of academic achievement against a formula based on grades and aptitude scores), the stunning truth is that the formula usually wins. Statistical predictions are, as you would expect, fallible. But when it comes to predicting the future, human intuition—even professional intuition—is even more fallible. Three decades after demonstrating the superiority of statistical pre- diction over intuition, University of Minnesota clinical researcher Paul Meehl, in a retrospective essay on what he called ‘‘my disturbing little book,’’ found the evidence more convincing than ever:

There is no controversy in social science which shows [so many] studies coming out so uniformly in the same direction as this one. . . . When you are pushing 90 investigations, predicting everything from the outcome of football games to the diagnosis of liver dis- ease and when you can hardly come up with a half dozen studies showing even a weak tendency in favor of the clinician, it is time to draw a practical conclusion.

The evidence continues to accumulate. In 1998 a Canadian Solici- tor General research team combined data from 64 samples of more than 25,000 mentally disordered criminal offenders. What best pre- dicted risk of future offending? As in studies with other types of criminal offenders, it was the amount of past criminal activity (il- lustrating once again the maxim that the best predictor of future behavior is past behavior). And what was among the least accurate predictors of future criminality? A clinician’s judgment.

A more recent review by a University of Minnesota research team combined data from 134 studies of clinical-intuitive versus statistical predictions of human behavior, or of psychological or medical prog- noses. Clinical intuition surpassed ‘‘mechanical’’ (statistical) predic- tion in only 8 studies. In 63 studies, statistical prediction fared better. The rest were a draw.

Would clinicians fare differently when allowed to conduct a first- hand clinical interview rather than just a file to read? Yes, reported the research team: allowed interviews, the clinicians fared worse. Many of these studies don’t engage the everyday judgments com- monly made by mental health professionals. Moreover, the studies often lump judgments by experienced and inexperienced clinicians.

Nevertheless, ‘‘it is fair to say that the ‘ball is in the clinicians’ court,’ ’’ the researchers concluded. ‘‘Given the overall deficit in clinicians’ accuracy relative to mechanical prediction, the burden falls on advo- cates of clinical prediction to show that clinical predictions are more [accurate or cost-effective].’’

In some contexts, we do accept the superiority of statistical predic- tion. For life insurance executives, actuarial prediction is the name of the game. Or imagine that someone says, ‘‘I just have a feeling about today’s presidential election. Something tells me X is going to win it.’’ If you have the same feeling, but then learn that ‘‘the final Gallup Poll is just out, and Y is ahead,’’ you probably know enough to switch your bet. Gallup Polls taken just before U.S. national elections over the past half-century have diverged from election results by an average of less than 2 percent. As a few drops of blood speak for the body, so a random sample speaks for a population.

But when it comes to judging individuals, intuitive confidence soars. In 1983, the U.S. Supreme Court ruled on a petition of mur- derer Thomas Barefoot. The petition challenged the reliability of psy- chiatric predictions of his dangerousness. Justice Harry Blackmun expressed skepticism of the clinical intuitions of two psychiatrists who testified for the prosecution. Although neither had examined Barefoot, one had testified with ‘‘reasonable medical certainty’’ that Barefoot would constitute a continuing threat to society. The other psychiatrist had concurred, noting that his professional skill was ‘‘par- ticular to the field of psychiatry and not to the average layman’’ and that there was a ‘‘one hundred percent and absolute’’ chance that Barefoot would constitute a continuing threat to society. Their clini- cal judgment carried the day, and on October 30, 1984, Texas officials executed Thomas Barefoot. Such testimony is junk science, argues experimental psychologist Margaret Hagen in Whores of the Court. Hagen grants a place for expert testimony about such things as the accuracy of eyewitness recall. But ‘‘psychobabble’’ by self-important experts is to psychological science what astrology is to astronomy, she says.

The limits of clinical intuition have also surfaced in false memory experiments. In three different studies, psychiatrists, psychologists, social workers, attorneys, and judges have evaluated children’s video-

taped testimonies. Could they discern which children were report- ing false memories formed during repeated suggestive questioning? The consistent finding: although often confident in their ability to winnow true from false memories, professionals actually did so at no better than chance levels. False memories feel and look like real memories.

What if we combined clinical intuition with statistical prediction? What if we gave professionals the statistical prediction of someone’s future academic performance or risk of violence or suicide, and asked them to improve on the prediction? Alas, notes Carnegie-Mellon Uni- versity psychologist Robyn Dawes, in the few studies where this has been done, prediction was better without the ‘‘improvements.’’

So what has been the effect of these studies on clinical practice? ‘‘The effect . . . can be summed up in a single word,’’ says Dawes. ‘‘Zilch.’’ Clinical researcher Paul Meehl, for example, was honored, elected to the American Psychological Association presidency at a very young age, elected to the National Academy of Sciences, and ignored.

Meehl himself attributed clinicians’ continuing confidence in their intuitive predictions to a ‘‘mistaken conception of ethics’’:

If I try to forecast something important about a college student, or a criminal, or a depressed patient by inefficient rather than effi- cient means, meanwhile charging this person or the taxpayer 10 times as much money as I would need to achieve greater predictive accuracy, that is not a sound ethical practice. That it feels better, warmer, and cuddlier to me as predictor is a shabby excuse indeed. . . . It will not do to say ‘‘I don’t care what the research shows, I am a clinician, so I rely on my clinical experience.’’ Clinical experience may be invoked when it’s all we have, when scientific evidence is insufficient (in quantity or quality) to tell us the answer. It is not a valid rebuttal when the research answer is negative. One who considers ‘‘My experience shows . . .’’ a valid reply to research studies is self-deceived, and must never have read the history of medicine, not to mention the psychology of superstitions. It is absurd, as well as arrogant, to pretend that acquiring a Ph.D. somehow immunized me from the errors of sampling, perception,

recording, retention, retrieval, and inference to which the human mind is subject.

Given our capacity for social intuition (Chapter 2) and intuitive expertise (Chapter 3), why does professional intuition fare so poorly?