The effect of imagery on explicit and implicit tests of memory in young and old people: a double dissociation

The use of imagery as an elaborative study task was examined to determine its effects on implicit and explicit tests of memory in both young and old adults. Both the implicit and explicit tests were word-stem completion tests, identical except for their instructional content. Results showed that imaging the referent of a visually-presented word during the initial study period significantly improved the performance of the young adults on the explicit test of memory, but reduced their performance on the implicit test. The test results of the elderly subjects showed a similar trend in that explicit test performance was significantly improved following an imagery study task whereas implicit test performance was reduced following this same task. These results did not, however, reach the level of significance, observed for young adults. The results are discussed within the framework of a processing account of implicit/explicit dissociations.