The role of the social sciences in preventing wrongful convictions.

AuthorMcMurtrie, Jacqueline

The lawyer alone is obdurate. The lawyer and the judge and the juryman are sure that they do not need the experimental psychologist. They do not wish to see that in this field preeminently applied experimental psychology has made strong strides.... They go on thinking that their legal instinct and their common sense supplies them with all that is needed and somewhat more.... The Court would rather listen for whole days to the "science" of the handwriting experts than allow a witness to be examined with regard to his memory and his power of perception, his attention and his association, his volition and his suggestibility, with methods which are in accord with the exact work of experimental psychology.

Hugo Munsterberg, On the Witness Stand 10, 46 (1908)


    The legal profession's reluctance to acknowledge the findings of social scientists, while accepting other "sciences" on little other than blind faith has contributed to the phenomena of erroneous convictions. It is undisputed that people are convicted and sentenced, sometimes to death, (1) for crimes they did not commit. (2) The advent of deoxyribonucleic (DNA) testing and rapid improvements in DNA technology have resulted in the exoneration of over 163 people in the United States. (3) As forensic DNA technology continues to evolve and improve, other forensic sciences, long accepted by courts as scientific proof of identification in criminal cases, have come under scrutiny. Individuals convicted on the basis of expert forensic testimony on comparisons of bitemarks, (4) hairs, voiceprints, earprints (5) and fingerprints, (6) were freed after post-conviction DNA tests established their innocence and proved the "scientific" evidence wrong. In one example, prosecutors stated that hairs found at a rape scene were "indistinguishable" from Jimmy Ray Bromgard's. With faulty statistics to bolster this bold statement, Bromgard, at eighteen, was sentenced to forty years in prison. Fifteen years later he was exonerated when DNA evidence proved he did not commit the rape. (7) In another case, the prosecutor's use of voiceprint analysis to match David Pope's voice with threatening messages left on the rape victim's answering machine following her attack sealed his conviction. Post-conviction DNA tests freed Pope, but only after he spent fifteen years in prison. (8)

    At the same time, studies of DNA exonerations and other erroneous convictions have validated the research of social scientists, particularly in the areas of mistaken eyewitness identification, false confessions and suggestibility of children. Courts traditionally tended to exclude scientific evidence from expert witnesses in these disciplines, primarily on the basis that the testimony addressed matters within the common understanding of jurors, (9) was confusing, (10) or that it invaded the province of the jury to make credibility determinations. (11) However, with the increased awareness of the role that mistaken identification, false confessions and suggestive interviewing of children play in convicting the innocent, a new trend is developing regarding the admissibility of expert testimony. Courts have more recently acknowledged that the research of social scientists in these areas contains findings that are counter-intuitive and therefore expert testimony can assist the trier of fact. (12)

    Section II of this essay will provide an introduction (the literature is far too extensive to attempt a comprehensive treatment in this article) to the findings of social scientists in the areas of: a) eyewitness identification; b) false confessions; and c) suggestibility of children. In each section, it will also discuss efforts to implement reforms based upon the research of social scientists. Any meaningful reform must take place on two fronts. First, it is essential that "obdurate" lawyers and judges address their preconceptions about the social sciences and educate themselves about the findings of applied psychology. Second, and most importantly, systemic change must occur in the way evidence is collected and preserved during the investigation of a case that involves an eyewitness, a child witness, or an interrogation. (13) By incorporating lessons learned from the research of social science, we can improve the administration of justice and guard against conviction of the innocent.


    The legal profession's relationship with the discipline of social sciences is complex and has vacillated between integration and isolation. James Ogloff traces the development of the law and psychology movement over the past century in Two Steps Forward and One Step Backward: The Law and Psychology Movement(s) in the 20th Century. (14) He discusses the genesis of the movement in the late 19th century and the promising "first step" of integrating social sciences, including psychology, into the law school curriculum. According to Ogloff, the movement took "one step back" in the late 1940s and 1950s, when virtually no articles or books are written on the general topic of law and psychology. The "second step forward" in the movement occurred in the 1960s, with the development of numerous scholarly journals devoted to the field of law and psychology and with the increase in the number of graduate programs in psychology and law. (15) Much of the social science research in the areas of eyewitness identification, interrogations, and interviewing of children that provides the foundation for reform in the criminal justice system was developed during the "second step forward" period of the law and psychology movement.

    1. Eyewitness Identification

      Mistaken eyewitness identification has long been recognized as a leading cause of wrongful convictions. The Supreme Court acknowledged the grave role that misidentifications play in the criminal justice system, indicating that mistaken identification "probably accounts for more miscarriages of justice than any other single factor." (16) Statistics bear out this observation, showing that mistaken eyewitness identification is the leading cause of conviction of the innocent-misidentification played a major role in two-thirds of the first 138 DNA exonerations in the United States. (17) Even before the development of forensic DNA testing, mistaken eyewitness identification was responsible for the convictions of more innocent persons than any other combination of factors. (18)

      Although DNA testing is a powerful tool in exonerating individuals convicted on the basis of mistaken identifications, it is not a panacea for eyewitness error in criminal cases. In most crimes involving eyewitnesses, such as murders, robberies, burglaries, and thefts, the perpetrator does not leave biological material at the scene of the crime. (19) However, procedures for maximizing accurate identifications and minimizing erroneous identifications have been extensively and empirically tested by cognitive and social psychologists, peer reviewed, and thoroughly and scientifically studied.

      Research over the past thirty years has shown that expert testimony on memory and eyewitness identification is the only legal safeguard that is effective in sensitizing jurors to eyewitness errors. (20) A 1984 Massachusetts case provides an interesting example of how expert testimony on eyewitness identification could change the outcome of a trial. In Commonwealth v. Francis, the defendant was convicted in the Superior Court of Massachusetts for armed robbery. (21) An eyewitness testified before the grand jury, at the probable cause hearing, and at the first trial that the robber was wearing short sleeves, and had no distinctive features. The trial ended in a mistrial when the jury was unable to reach a verdict after the defendant showed that he had tattoos up and down his arms.

      At the second trial, after the eyewitness (who had been sequestered during the first trial) learned about the defendant's tattoos, she changed her testimony, suddenly remembering that the robber wore a long-sleeved jacket which concealed his weapon. (22) At this point, the defendant moved to allow expert testimony regarding eyewitness identification. The expert for the defense testified that high levels of stress and the presence of a weapon reduce the ability of an eyewitness to correctly identify a suspect. The expert also testified that when an eyewitness learns of inconsistent post-event information, she will often unconsciously alter her memory to resolve the conflict, incorporating this post-event information into her memory. (23)

      The trial judge refused to admit the expert testimony, stating that "the proposed testimony is not beyond the ordinary experience and knowledge of the average juror, and would not aid jurors in their deliberations." (24) The defendant, despite an alibi and the presence of the tattoos, was convicted. However, the undecided jury at the first trial, and the cross examination of the witness at the second trial, revealing her prior inconsistent statements, suggests that had the expert testimony been admitted, the defendant may well have been acquitted.

      In light of the research exposing the weaknesses of eyewitness identification, the Francis and other courts' traditional reliance on cross-examination and closing argument (25) and on the common sense of jurors to understand the flaws of eyewitness identification is misguided. Although cross-examination is a powerful tool for exposing lies, it is not particularly effective when used against eyewitnesses who believe they are telling the truth. (26) Further, reliance upon a fact-finder's common sense is misplaced when social science research concludes that many of the findings in the area of eyewitness identification are counter-intuitive.

      For example, extensive scientific research establishes that high confidence on the part of an eyewitness does not directly correlate with high accuracy. (27) Yet, the...

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