The Province of the Jurist: Judicial Resistance to Expert Testimony on Eyewitnesses as Institutional Rivalry

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I. INTRODUCTION

Expert testimony on eyewitness identifications is one of the most controversial issues in evidentiary procedure today. (1) With false identifications recognized as a leading cause of wrongful convictions in the United States, (2) numerous commentators have urged courts to expand the use of expert testimony to educate jurors about the shortcomings of eyewitnesses. (3) The Supreme Court's recent decision in Perry v. New Hampshire (4) heightened the stakes of the debate, identifying the availability of expert testimony among its reasons for refusing to strengthen judicial filters against admittedly unreliable identifications. (5) Yet admission of expert testimony on eyewitness identifications remains the exception rather than the rule. (6) Because the unreliability of eyewitness testimony is a matter of "common knowledge" among lay jurors, courts insist, juries are competent to evaluate eyewitnesses without the benefit of any specialized expertise -- to impeach faulty evidence "using their common-sense and faculties of observation" alone. (7)

While courts formally justify their exclusion of experts based on the sufficiency of the jury's common-sense authority over eyewitness evidence, even judges who acknowledge the dramatic deficiencies in jurors' knowledge on eyewitness identifications resist admitting expert testimony on the subject. (8) Instead, these judges insist on addressing the limitations of lay juror knowledge through traditional safeguards, most notably cross-examination by opposing Counsel (9) and cautionary jury instructions issued by trial judges. (10) Especially in light of emerging research on the substantive shortcomings of such procedures, courts' insistence on the inability of scientific experts to contribute meaningfully to the trial process presents a marked contrast to courts' typical humility about their institutional competence. (11)

This Note suggests that the traditional concern with preserving the so-called "province of the jury" - that is, with defending the lay competence of the jury against the denigrations of scientific expertise - may not be the only, or even the leading, motive behind courts' continued aversion to expert testimony on eyewitness identifications. While presented as a core site of the lay jury's democratic authority in the courtroom, eyewitness testimony in fact provides a central arena for courts to affirm the rarefied expertise of trained jurists at trial - to defend the professional authority of lawyers and judges against encroachment by a rival body of experts in their traditional sphere of competence. Commentators have characterized courts' traditional resistance to expert testimony, and the continuing exclusion of eyewitness experts specifically, as a struggle against the "professionalization" by scientists of factfinding duties formally vested in the lay jury. (12) This Note suggests that the continuing exclusion of expert testimony may seek less to protect the lay authority of the jury within the American trial system than to affirm the professionalization of American trial procedure by lawyers and judges.

Before continuing, a word on methodology. This Note examines a set of federal opinions on eyewitness identifications as a case study of the role of expertise and professionalization in the courtroom. (13) It does not attempt to suggest that the broader trends of professionalization or institutional rivalry examined are limited to the context of eyewitness identifications. As discussed below, however, eyewitness identification provides a particularly salient window into these trends due to the mass of accumulating scientific research on the subject, the persisting assumption that visual memory is a uniquely common-sense phenomenon, and courts' traditional authority over witness credibility. (14)

The remainder of this Note proceeds in four parts. Part II examines the traditional justification for excluding expert testimony on eyewitness identifications: protecting the province of the jury. …