Stronger Mnemonic Prediction Errors Can Disproportionately Impair Memory Updating in Older Adults

Mnemonic prediction errors are discrepancies between memory-based expectations and actualevents that can trigger memory updating. However, the conditions under which these predictionerrors result in successful memory updating, and whether these effects vary between younger andolder adults, remain less understood. In two experiments, the present study investigated howprediction strength affects memory for events that violated memory-based expectations inyounger and older adults. Prediction strength was manipulated by first presenting three-wordsequences (i.e., trains), each with exemplars from the same category (Bluejay–Hawk–Eagle),either once or four times. Predictions based on memory for trains were then confirmed byrepeating sequences entirely (Bluejay–Hawk–Eagle) or violated by repeating the first two wordsand changing the ending word (Bluejay–Hawk–Robin). Differences in prediction strength,created by varying repetitions, were validated using retrospective judgments (Experiment 1) andprospective predictions of original train endings along with confidence ratings (Experiment 2).Prediction error effects on memory updating were assessed by presenting the first two words oftrains as cues for recalling changed ending words. Stronger predictions impaired memory forchanged endings disproportionately for older adults, and older adults were less able to recollectthat endings had changed when asked directly. Regardless of prediction strength and age, changerecollection was consistently associated with better memory for changed ending words.Collectively, these findings suggest that stronger mnemonic predictions exacerbate the negativeimpact of prediction errors on the resolution of proactive interference, an ability that is oftenimpaired in healthy aging.