Implicit associative memory remains intact with age and extends to target-distractor pairs

Abstract

Past research has shown that older adults’ reduced inhibitory control causes them to hyper-bind, or form erroneous associations between task-relevant and -irrelevant information. In the current study, we aimed to extend hyper-binding to a novel, implicit memory paradigm. In two experiments, participants viewed pictures of objects superimposed with text and their task was to make speeded categorization judgments about the objects. The encoding phase contained three blocks that varied the potential for binding: no-binding, some-binding, and full-binding. During the no/some-binding blocks, participants decided if the pictured object alone could fit inside a common desk drawer while ignoring the superimposed text. In the no-binding block, the text was a nonword; in the some-binding block, it was an object word. During the full-binding block, participants attended to both the picture and word and decided if both items could fit inside a drawer together. After a delay, participants completed the test phase during which they viewed intact and rearranged pairs from the three encoding blocks and decided if both items could fit in a drawer together. In both experiments, older adults responded faster to intact than rearranged pairs from both the some- and full-binding blocks, suggesting that they had learned both target-target and target-distractor pairs. Young adults showed no difference in RTs to pairs from either block. These findings suggest that the binding mechanism itself is spared with age; what declines instead is inhibitory control, which serves to limit attention, and ergo binding, to task-relevant information.