Co-Witness Confidence, Conformity, and Eyewitness Memory: An Examination of Normative and Informational Social Influences

Summary: We explored conformity and co-witness confidence in eyewitness memory. Confederates provided misleading information and confidence ratingsduring acuedrecalltest, and participants publiclyprovidedanswers tothistest inturn.Participantsperformed memory tests witha confederate, then completed individual memory tests. Results indicated that confederates who answered questions prior to participants impacted their public and private memory reports for accurate information but only impacted public reports for misleading information. Participants’ confidence in their performance in the presence of a confederate mirrored the confederate’s confidence levels, suggesting a confidence conformity effect. Results are explained in terms of differential effects of informational and normative influence for accuracy and confidence in co-witness memory reports. Copyright © 2012 John Wiley & Sons, Ltd. One factor that contributes to mistaken eyewitness identification is the commonly held belief that the more confidence a witness has in a memory for an event, the more accurate one’s memory is for that event. This generally accepted belief that confidence indicates accuracy was determined by the US Supreme Court in Neil v. Biggers (1972) to be a factor when determining the accuracy of a witness. However, empirical study of the relationship between eyewitness confidence and memory shows that the relationship between and confidence and eyewitness accuracy is weak, with many studies demonstrating that confidence in one’s memory does not consistently indicate memory accuracy (Bothwell, Deffenbacher, & Brigham, 1987; Leippe & Eisenstadt, 2007; Lindsay, Read, & Sharma, 1998; Luus & Wells, 1994; Penrod & Cutler, 1995; Read, Lindsay, & Nicholls, 1998; Shaw, McClure, & Dykstra, 2007). Another factor that pervades the eyewitness memory literature is the role of postevent information (PEI) in accuracy (Davis & Loftus, 2007; Ross, Read, & Toglia, 1994). Witnesses to an event often encounter PEI when speaking with other witnesses about an event before reporting it, and it is well established that such co-witness discussion can alter one’s memory for the original event (Memon & Wright, 1999; Wright, Self, & Justice, 2000). Acceptance of PEI provided by co-witnesses may be due to memory conformity, in which co-witnesses alter their memory reports to coincide with other witnesses’ reports (Gabbert, Memon, & Allan, 2003; Roediger, 2010). To assess the effects of discussing an event with others on memory, one approach has been to utilize a confederate to provide misleading PEI in order to sway the real participant to conform to the confederate’s answers. Often, participants conform to the confederates’ reports and provide inaccurate eyewitness reports (Gabbert, Memon, Allan, & Wright, 2004; Mudd & Govern, 2004; Wright, Mathews, & Skagerberg, 2005). What has not been demonstrated is the extent to which a co-witness who exhibits different levels of confidence would produce differential conformity effects on their fellow witnesses’ reports. Thus, the goal of our research was to examine the effects of confidence and conformity on memory for a witnessed event.