Memory mistakes and ageing : how susceptibility to false recognition and the illusory truth effect changes across the lifespan : a thesis presented in partial fulfilment of the requirements for the degree of Master of Arts in Psychology at Massey University, Manawatu, New Zealand

Abstract

The purpose of the current research was to investigate if there was a common susceptibility to false memories and the illusory truth effect, and how performance in these two tasks varied with age. False memories were investigated using the Deese (1959) Roediger and McDermott (1995) (DRM) recognition paradigm, and the illusory truth effect was examined by asking participants to read and rate a set of statements labelled as true or false, and then soon after rate the truth of a subset of the previously presented statements amongst a set of new statements. The study followed a quasi-experimental, within/between-subjects design. The participants were 161 individuals aged from 16 to 92 years old. The sample was divided into three similar-sized age groups: young (16-39), middle (40-60), and old (61+). It was hypothesised that there would be a common susceptibility to DRM false memories and the illusory truth effect, and that older adults would perform more poorly than the young and middle age groups on the two tasks, and that the middle age group would perform more poorly on the two tasks than the young group. The results showed that only the old group demonstrated a common susceptibility to the two tasks. Unexpectedly, there were no age-related differences in the DRM false recognition task. However, in the illusory truth effect task the older groups’ performance was poorer compared to the younger two groups, but performance did not differ between the young and middle age groups. These results (along with others) are discussed in relation to the mechanisms believed to underpin performance in the two tasks.