Expert Testimony: Does Eyewitness Memory Research Have Probative Value for the Courts?
Yarmey, A Daniel, Canadian Psychology
Case studies, and more recently DNA testing in the United States, have shown that mistaken eyewitness identification is responsible for more wrongful convictions than all other causes combined. It is argued that scientific laboratory and field research can contribute to the court's better understanding of those factors which contribute to both accurate and mistaken eyewitness recall and identification. Attention is given to the value of common knowledge in prediction of eyewitness memory performance, to the major critiques of expert eyewitness testimony, and to the worth of legal safeguards designed to prevent false identification leading to wrongful convictions. Expert eyewitness testimony provides an opportunity for the trier of fact to be assisted in decision-making such that convictions of innocent suspects may be minimized, and the just conviction of guilty suspects maximized.
Eyewitnesses have been giving testimony in Englishspeaking courts since the late 16`" century. Expert testimony on eyewitness memory, however, is relatively recent and still an infrequent event. In fact, following the Ontario Court of Appeal decision in Regina v. McIntosh and McCarthy (1997), expert eyewitness testimony in the province of Ontario appears to have been put on hold until further notice. The trial judge and the Court of Appeal in McIntosh and McCarthy concluded that expert testimony would not be more than common knowledge, and would not assist the jurors in their deliberations. The major purposes of this paper are to present an overview of some of the challenges an expert witness in eyewitness memory typically faces, some of the responses that can be made to these challenges, and some data from a recently completed study which addresses the notion that we have more to offer the courts than mere common sense.
Nearly 100 years ago, Hugo Munsterberg (1908) argued that because experimental psychology concerns itself with the scientific study of human behaviour and experience, the results of laboratory studies on human perception and memory should be especially relevant to American courts' evaluations of witness testimony. Unfortunately, Munsterberg's proposals lacked sufficient empirical support and attacked the legal establishment for their lack of appreciation and endorsement of psychology's offerings. Justice Wigmore (1909) answered Munsterberg by writing a satirical and crushing review of his thesis. In spite of this relatively poor introduction to an integration of the psychology of testimony and law, Wigmore and other legal scholars of that period encouraged the application of scientifically valid research findings to the courts' better understanding of witness testimony (Sporer, 1982). Unlike Europe, there was little interest in America in developing a rapprochement between the psychology of testimony and the courts until the 1970s (e.g., Buckhout, 1974; Clifford & Bull, 1978; Loftus, 1979; Yarmey, 1979). Furthermore, unlike Munsterberg, contemporary psychology has not suggested that the courts submit to an alternative authority. Over the last two decades, valuable advances in the scientific understanding of eyewitness perception and memory have been made which can assist the court in their evaluations of eyewitnesses' reports. Furthermore, Canadian psychology students and law students now have a textbook (Schuller & Ogloff, in press) which emphasizes Canadian perspectives on an integration of the law and psychology, including eyewitness testimony (Read, Connolly, & Turtle, in press).
The reality that eyewitnesses make errors and innocent people are convicted based upon faulty identifications is accepted by Canadian legal professionals (Brooks, 1983). Perhaps what is not fully appreciated is the fact that eyewitness misidentifications are the single most common cause of wrongful convictions (Huff, Rattne, & Sagarin, 1986). Next to an actual confession, eyewitness testimony has been described as the most incriminating evidence that can be introduced against an accused (Brandon & Davies, 1973). …