Memory Conjunction Errors in Younger and Older Adults: Event-related Potential and Neuropsychological Data

In a study/recognition paradigm, new words at test were recombinations of studied syllables (e.g. BARLEY from BARTER and VALLEY), shared one syllable with studied words, or were completely new. False alarm rates followed the gradient of similarity with studied items. Event-related potentials to the three classes of false alarms were indistinguishable. False alarms elicited different brain activity than did hits, arguing against the idea that conjunction errors occur during encoding and are later retrieved liked genuine memories. In Experiment 2, with healthy older adults, neuropsychological tests sensitive to frontal lobe function predicted false alarm rate, but not hit rate. Performance on standardised memory scales sensitive to medial temporal/diencephalic function influenced the pattern of false alarm rates across the three classes of new words. The experiments suggest that false alarms to conjunction lures are not similar to true recollections, but are products of faulty monitoring at retrieval.