The Role of Informativeness in Eyewitness Memory Reporting

Author: Nicole Amy Reid

Reid, Nicole Amy, 2014 The Role of Informativeness in Eyewitness Memory Reporting, Flinders University, School of Psychology

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Koriat and Goldsmith (1996) proposed that, when determining whether information from memory will be reported, people go through a process of memorial monitoring and control. Monitoring involves ascertaining the likely accuracy of a piece of information by gauging confidence in the information, and control reflects the decision to report or withhold this information. However, research indicates that people do not always adhere to the monitoring and control model when deciding what information they will report. Coarse-grain (broad, general) information is at times withheld from eyewitness memory reports despite being available in memory, likely correct and potentially quite valuable (Ackerman & Goldsmith, 2008; Brewer, Hope, Gabbert, & Nagesh, 2014; Yaniv & Foster, 1995). The memory reporting literature suggests that coarse-grain information may be withheld from eyewitness testimony because people are motivated to be informative. Informativeness is defined in the literature as the amount of detail conveyed (Goldsmith, Koriat, & Panksy, 2005; Weber & Brewer, 2008; Yaniv & Foster, 1995). That is, an answer is considered informative if it is specific, capturing fine detail. Fine-grain information is more specific and thus more informative than coarse-grain information (Yaniv & Foster, 1995). Accordingly, people may withhold coarse-grain information because they have a preference for reporting fine-grain information and being specific. This thesis examined the role of informativeness in the withholding of coarse-grain information. Study 1 investigated social motivation for informativeness, exploring whether socially motivating conditions could overcome the preference for reporting fine-grain information. The results indicated that preference for specificity was resistant to social context. Study 2 ascertained whether this preference for specificity would remain, even under circumstances where coarse-grain information was potentially more valuable than fine-grain information. Preference for specificity again prevailed, demonstrating the pervasiveness of this bias. As Studies 1 and 2 were unable to increase reporting of coarse-grain information, I investigated participants' perceptions of informativeness in Study 3, in anticipation that this would provide an insight into why coarse-grain information is at times withheld. Results indicated that, when forming perceptions of informativeness, in addition to gauging the specificity of the information, participants also judged its value and the potential effect that volunteering this information would have on their image. Further, Study 4 results demonstrated that these perceptions of informativeness significantly predicted memory reporting. Finally, in Studies 5a-c, I attempted to manipulate, albeit unsuccessfully, perceptions of informativeness, to determine whether the nature of eyewitness memory reporting could be changed. Across all studies, confidence significantly predicted the accuracy of retrieved information, suggesting that coarse-grain information was not withheld through ineffective monitoring ability and that perhaps deficient control and poor decision making was responsible for this behaviour. Taken together, these results provide clear evidence that eyewitnesses withhold coarse-grain information from their memory reports because they are motivated to be informative and they do not want to volunteer information that they perceive to be uninformative. Further, perceptions of informativeness seem to affect reporting by influencing the process of control, prompting poor decision making. This thesis demonstrates why and how eyewitnesses sometimes withhold coarse-grain information from their memory reports and provides insight into fine-grain preference, perceptions of informativeness and coarse-grain withholding. Further, the findings from this thesis suggest that the conceptualisation of informativeness in the literature requires revision and that perhaps the monitoring and control model could be expanded to include the effect of informativeness.

Keywords: Eyewitness memory,memory reporting,informativeness,grain size

Subject: Psychology thesis

Thesis type: Doctor of Philosophy
Completed: 2014
School: School of Psychology
Supervisor: Neil Brewer