Intending to forget: the development of cognitive inhibition in directed forgetting.

The thesis of this research is that children's cognitive inhibition increases in efficiency with age over the middle childhood years, and this increasing efficiency contributes to developmental improvements in memory performance. To explore this thesis, the development of efficient retrieval inhibition, defined as the suppression of activation and retrieval paths to information stored in long-term memory, was investigated. In Experiment 1, first, third, and fifth graders and adults participated in a directed-forgetting experiment. Using a blocked-cuing procedure, subjects were given a "forget" or "remember" cue halfway through an unrelated free-recall list. At recall, subjects were asked either to remember all the words (even the ones they had been instructed to forget) or to remember only to-be-remembered words. The results suggested that the ability to intentionally inhibit the maintenance and recall of irrelevant information improves gradually over the elementary school years, but is not fully mature by fifth grade. Children were less able than adults to inhibit the to-be-forgotten words, and they were less able to withhold production of remembered to-be-forgotten words than were adults. Experiment 2 replicated the development effects found in the first experiment and demonstrated that the developmental differences in performance were due to differences in mnemonic processing rather than differences in the ability to understand the instructions of the tasks.