Effects of age and study repetition on plurality discrimination

Previous studies have shown that false recognition decreases with study repetition for young but not for older adults, suggesting a deficit in recollection but not familiarity in old age. It is unclear, however, precisely how false recognition changes over a series of presentation frequencies for young and older adults. The present study examined this issue using a plurality discrimination task in which young, young-old, and old-old adults studied singular and plural nouns 1, 2, 4, and 8 times. False alarms to plurality-reversed lures increased with repetition for all age groups, and then declined at higher repetitions for young and young-old but not for old-old adults. Recollection deficit thus occurred at a more advanced age than researchers had previously envisioned. Further, reducing recollection demand eliminated age-related differences in plurality discrimination.