Effects of Deception on Eyewitness Reports
Yarmey, Daniel, Canadian Journal of Police and Security Services
Lay persons were presented with a written description of an armed robbery and shooting and asked to assume that they were witnesses to the crime. Participants were randomly assigned to a truthful role playing condition or a deceptive condition, and asked to indicate how they would respond to questions about perpetrator characteristics and lineup identification. Both truthful and deceptive witnesses had a bias toward overestimation of perpetrator characteristics of height, weight, and age. As expected, the bias was greater for deceptive witnesses than for truthful witnesses. However, this result was influenced by the gender of participants in the deceptive condition, and the duration of the criminal incident. Most truthful witnesses expected to be highly accurate and confident in their identification of the suspect from a photo lineup. Most deceptive witnesses indicated that they would say either that the suspect was not present or that they did not know. Contrary to expectations, a substantial percentage of deceptive witnesses indicated that they would correctly select the perpetrator in spite of possible retribution from friends of the suspect.
The objectives of police interviews of eyewitnesses are to determine whether a crime has occurred; to obtain accurate descriptions and evidence which can identify the individual(s) involved; and to determine the credibility and truthfulness of the eyewitnesses (Gudjonsson, 1992; Kebbell & Wagstaff, 1997). Although eyewitness descriptions and identification are recognized to be fallible (Cutler & Penrod, 1995, Manitoba, 2001), it is also acknowledged that eyewitnesses are not always honest and cooperative with the police. Eyewitnesses may lie for a number of reasons, including fear of retribution if they tell the truth (Parliament & Yarmey, 2002; Yarmey, 2003a).
The present investigation examined citizens' anticipated responses regarding their eyewitness reports if coerced to lie to protect a perpetrator, in contrast to being truthful and accurate as possible. Participants were given a description of an armed robbery and shooting of a store clerk and asked to assume that they were the sole eyewitness to the crime. Half of the participants were instructed to adopt the role of deceptive witnesses. They were told that they and their family would be harmed if they did not protect the perpetrators in their eyewitness reports. The remaining participants were asked to respond as truthful witnesses. Participants were instructed to state their expected accuracy/distortion of reports in estimating the height, weight, and age of a male and female perpetrator, their estimation of the duration of the incident, and their identification decision regarding a male suspect in a photo lineup.
Because the information given to participants involved a written schematic description of an armed robbery and shooting, participants' reports about their likely behaviour would have to be based on their common knowledge of eyewitness testimony, personal values, and beliefs. Common knowledge understanding of the accuracy of eyewitness memory is dependant in part upon intuitions, past experiences, and confidence in perceptual and cognitive abilities (Yarmey, 2003b). Previous studies of common knowledge of eyewitness memory have followed a variety of approaches such as: the use of questionnaires (e.g., Brigham & WolfsKeil, 1983; Deffenbacher & Loftus, 1982; Rahaim & Brodsky, 1982; Yarmey & Jones, 1982, 1983); written descriptions of trials or videotaped trials (e.g., Hosch, Beck, & McIntyre, 1980; Wells, Lindsay, & Tousignant, 1980); prediction studies of the accuracy of eyewitness identification in staged crimes (e.g., Kassin, 1979; Leippe, Wells, & Ostrom, 1978); and the cross-examination of eyewitnesses to staged crimes (e.g., Wells, Lindsay & Ferguson, 1979; Lindsay, Wells, & Rumpel, 1981). These different procedures have found relatively consistent results, that is, laypersons (potential jurors) as well as police officers, lawyers, and trial judges have poor understanding of many issues involved in eyewitness memory (see also, Devenport, Cutler and Penrod, 1997; Stinson, Devenport, Cutler, & Kravitz, 1996,1997). …