Confidence of older eyewitnesses: Is it diagnostic of identification accuracy?

Since the late 1980s evidence has been accumulating that confidence recorded at the time of identification is a reliable postdictor of eyewitness identification. Nonetheless, there may be noteworthy exceptions. In a re-analysis of a field study by Sauerland and Sporer (2009; N = 720; n = 436 choosers between 15 and 83 years old) we show that the postdictive value of confidence was reduced for participants aged 40 years or older. Different calibration indices and Bayesian analyses demonstrate a progressive dissociation between identification performance and confidence across age groups. While the confidence expressed following an identification remained unchanged across the lifespan, identification accuracy decreased. Young, highly confident witnesses were much more likely to be accurate than less confident witnesses. With increasing age, witnesses were more likely to be overconfident, particularly at the medium and high levels of confidence, and the postdictive value of confidence and decision times decreased. We conclude that witness age may be an important moderator to take into account when evaluating identification evidence.