Process dissociation procedure reveals age differences in unconscious influences on memory for possible and impossible objects

Abstract
Forty-eight younger and 48 older adults performed inclusion and exclusion tasks for line drawings of possible and impossible objects that were encoded semantically or globally. Participants' performance was transformed into estimates of conscious and unconscious influences on memory via the Process Dissociation Procedure (PDP). Five major findings were obtained. First, developmental differences were observed in the relative strength of conscious and unconscious influences on memory such that conscious influences were stronger for younger than older adults, whereas unconscious influences were stronger for older than younger adults. Second, unconscious influences on memory were demonstrated for possible and impossible objects. Third, unconscious influences on memory were obtained for objects that were encoded in both a global and a semantic fashion. Fourth, age-related differences in conscious and unconscious influences on memory were unaffected by object type. Fifth, estimates of conscious and unconscious influences on memory were unrelated to scores on psychometric measures of visual-spatial ability: Primary Mental Ability-Space (PMA-Space) and Benton Facial Recognition Task (BFRT). Collectively, these findings have implications for our understanding of the relative strength of conscious and unconscious memory processes in younger and older adults as well as the different types of unconscious memory processes that are recruited by the PDP in comparison to the traditional priming methodology.