Effects of distinctive encoding on source-based false recognition: further examination of recall-to-reject processes in aging and Alzheimer disease.

OBJECTIVE To examine the use of distinctive materials at encoding on recall-to-reject monitoring processes in aging and Alzheimer disease (AD). BACKGROUND AD patients, and to a lesser extent older adults, have shown an impaired ability to use recollection-based monitoring processes (eg, recall-to-reject) to avoid various types of false memories, such as source-based false recognition. METHOD Younger adults, healthy older adults, and AD patients engaged in an incidental learning task, in which critical category exemplars were either accompanied by a distinctive picture or were presented as only words. Later, participants studied a series of categorized lists in which several typical exemplars were omitted and were then given a source memory test. RESULTS Both older and younger adults made more accurate source attributions after picture encoding compared with word-only encoding, whereas AD patients did not exhibit this distinctiveness effect. CONCLUSIONS These results extend those of previous studies showing that monitoring in older adults can be enhanced with distinctive encoding, and suggest that such monitoring processes in AD patients many be insensitive to distinctiveness.