Calibration of Confidence among Eyewitnesses and Earwitnesses

Abstract

One of the results in forensic psychology is the weak relationship between confidence and accuracy in experimental studies of eyewitness identification. This relationship has traditionally been measured by the point-biserial correlation coefficient rpb. In this chapter the confidence-accuracy relationship in witness identification was studied with 2 alternative indices, namely calibration and diagnosticity analysis. The results of 3 empirical studies are presented. In Study 1 (P. Juslin, N. Olsson and A. Winman, 1996) it was concluded from 2 experiments that eyewitness confidence can be both reasonably well calibrated and diagnostic, despite low rpb. Study II (Olsson, Juslin and Winman, 1998) showed that in comparison to eyewitness identification in similar circumstances, earwitness accuracy was poorer, with overconfidence and low diagnositicity of confidence, even in easy tasks. In Study III (Olsson, 2000), a meta-analysis showed that the measures rpb and calibration were weakly correlated. A modest relation was observed between the rpb and the diagnosticity index. The calibration and over/underconfidence scores co-varied with task difficulty. Overconfidence was again observed for voice identification tasks. (PsycINFO Database Record (c) 2016 APA, all rights reserved)