Age differences in recognition memory : the effects of stimulus presentation mode, stimulus type, and trial difficulty : thesis presented in partial fulfilment of the requirements for the degree of Master of Arts in Psychology at Massey University
Forty young and 40 older adults completed a verbal and non-verbal recognition task to determine whether there were age differences in recognition memory for three factors. The between-group factors included the age of the participant (young vs. older) and the mode of stimulus presentation (one-alternative, forced choice vs. two-alternative, forced choice). The within-group factors were the type of stimulus (words vs. shapes) and the level of trial difficulty, as indicated by the degree of target-distractor similarity (similar vs. dissimilar). Signal detection analyses indicated that recognition accuracy declined with age. Older adults showed consistently poorer recognition than their younger counterparts. In contrast to the pictorial superiority effect, recognition accuracy was impaired across the lifespan for non-verbal as opposed to verbal stimuli. In accordance with previous studies, items that were high in target-distractor similarity were recognised at lower rates than items that were low in target-distractor similarity. When the two-alternative, forced choice data were transformed to d' and adjusted for comparison with the one-alternative, forced choice data, the effect of Presentation Mode disappeared. This result is in accordance with the predictions of signal detection theory. In addition to the main effects, a significant Stimulus Type x Trial Difficulty x Presentation Mode, and Presentation Mode x Age interaction emerged, which qualified the interpretation of the main effects.