Implanting rich autobiographical false memories: Meta-analysis for forensic practice and judicial judgment making

Abstract

Objective. The implanting of rich autobiographical false memories is crucial for judicial decision–making, and the forensic evaluation of a testimony. In order to assess this issue, a meta–analytical review of the probability of implanting rich autobiographical false memories was performed. Method. A total of 30 primary studies analysing the probability of implanting rich autobiographical false memories were retrieved. Random–effects meta–analyses correcting the effect size for sampling error were performed. Results. The results revealed a significant, positive, generalizable (the lower limit for the 80% credibility value was d = 1.13), and more than large mean effect size (d = 1.43[1.33, 1.53]) for the implanting of false memory. The moderating effects of stimulus type showed that the effect of the probability of implanted false memory was significantly higher in experienced events (d = 2.03[1.63, 2.43]) than in false narratives (d = 1.35[1.23, 1.47]), and in doctored photographs (d = 1.29[1.06, 1.52]). A similar effect for memory implantation was observed in both the underage (d = 1.44[1.29, 1.59]), and in adults (d = 1.36[1.22, 1.50]). The moderator techniques for implanting false memories revealed a significantly lower probability of implanting false rich memory with non–directive instructions (d = 0.90[0.53, 1.27]) than with guided imagery (d = 1.45[1.32, 1.58]), or with pressure to answer (d = 1.56[1.17, 1.95]) instructions. The event emotional valence moderator exhibited the same effect for positive (d = 1.27[1.09, 1.45]) and negative valence events (d = 1.30[1.17, 1.43]). Conclusions. The implications of the results for forensic testimony evaluation, police interrogations, and judicial cross–examination are discussed.