"The certainty of the eyewitness has been enshrined by the U.S. Supreme Court as a primary factor for judges to consider in deciding whether the identification by an eyewitness is accurate," write Gary Wells, Ph.D., Elizabeth Olson, Ph.D. student and Steve Charman, Ph.D. student, of Iowa State University. Knowing that immediate feedback after identification (confirming, disconfirming or neutral) could distort things in witnesses' minds in a way that ultimately determines whether their testimony is accepted, police had curbed on-the-spot comments such as "Good, you identified the suspect," or "No, that person was just a lineup filler." However, law enforcers (including the FBI) allow feedback later -- perhaps on a ride home from the police station, in a later interview with an agent, or in a pre-hearing briefing from a prosecutor -- contending that the delay softens the power of feedback.
To investigate whether that was true, psychologists Wells, Olson and Charman showed staged crime videos to 253 participants and then had them single out a suspect -- from a lineup lacking the video culprit. The researchers then gave the participants (who didn't know they were mistaken) either immediate or delayed 48-hour feedback that confirmed, disconfirmed or was neutral about the identification.
Confirming ("Good, you identified the suspect") but not disconfirming ("It was really #3") feedback led to significant distortions. Witnesses given confirming feedback overestimated how confident they were at the time of the identification, how much attention they paid while witnessing the crime, how good their view was of the video culprit, their ability to make out facial details, and other measures related to the witnessing experience. Clearly, delaying feedback did not moderate the power of post-identification feedback.
Wells and his colleagues make the case that eyewitnesses do not form clear impressions of how confident they are, how good their view is and so on, during the actual crime or event. "Instead," the authors say, "eyewitnesses construct impressions of these matters at a later time when they are asked retrospective questions about their witnessing experience."
What's more, eyewitnesses have no awareness that feedback has shaped their highly malleable impressions. Thus, the authors strongly support recommendations for double-blind lineup procedures and securing confidence statements at the time of the identification, prior to feedback.
Article: "Distorted Retrospective Eyewitness Reports as Functions of Feedback and Delay," Gary L. Wells, Ph.D.; Elizabeth A. Olson, Ph.D. student, and Steve D. Charman, Ph.D. student, Iowa State University; Journal of Experimental Psychology: Applied, Vol. 9, No. 1.
Full text of the article is available from the APA Public Affairs Office or at http://www.apa.org/journals/xap/press_releases/march_2003/xap9142.html.
Gary Wells can be reached by email at glwells@iastate.edu, or by phone at 515-294-6033. The American Psychological Association (APA), in Washington, DC, is the largest scientific and professional organization representing psychology in the United States and is the world's largest association of psychologists. APA's membership includes more than 155,000 researchers, educators, clinicians, consultants and students. Through its divisions in 53 subfields of psychology and affiliations with 60 state, territorial and Canadian provincial associations, APA works to advance psychology as a science, as a profession and as a means of promoting health, education and human welfare.