always looks more like the perpetrator than the other people in the lineup, witnesses tend to choose that person rather than choosing no one. By using a sequential system, in which witnesses were shown a single pic-ture at a time without knowing whether they would see any more, the accuracy rate rose significantly.

Even after this finding had been established, however, the court system resisted any changes. Psychologists tried explaining it directly to the police, testifying as expert witnesses in court, and talking to the media. But general change did not begin until DNA testing arrived in the 1990s. It soon became apparent that DNA evidence had the capacity not only to convict but to exonerate those convicted mistakenly. Criminal justice researchers were able to show that 84 percent of these mistaken convic-tions were based on eyewitness evidence. In 1997, Attorney General Janet Reno, having seen this evidence, ordered the National Institute of Justice to develop the first set of national guidelines on eyewitness evidence and to include the substantial body of findings regarding eyewitness evidence produced by research psychologists. This set in motion the substantial change that has now taken place.

The social scientist listed several factors that finally led to change: (1) the scientists had clear experimental evidence; (2) they had publicized that evidence in leading, peer-reviewed psychology journals; and (3) they developed their own policy recommendations based on evidence, learned which policy makers could effect change, and lobbied those policy makers for change.


The session moderator, a scientist, suggested that courts may ask several questions about research whose results are used to influence court proceedings. First, does the content of the research meet the standards for scientific evidence discussed in Daubert? Second, is the provenance of the evidence appropriate: Is the organization or the person who did the research trustworthy? In what context was it issued?

The moderator went on to say that experts bringing evidence to trials may gather their information in two ways. The first is “before-the-fact” science, where the literature in the field is surveyed and presented by the expert. The second is “after-the-fact” science in which actual experiments or other research is done to answer a question in the context of particular litigation (such as the breast implant controversy). After-the-fact science has several virtues. It is relatively frugal, because the goal is clear and specific, and it is highly focused, so that the scientist can design the research to answer a specific question.

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