Age-related differences in semantic priming: Evidence from event-related brain potentials

Hasher and Zacks (1988) suggested that aging may affect processes involved in the inhibition of irrelevant information during language processing. Our experiment tested this hypothesis using the N400 event-related brain poten tial in a priming paradigm and assessed whether older subjects could benefi t from the constraints of a sentence context. Twenty older (63 to 88 years) and 70 young (19 to 29 years) subjects read sentences and word pairs. Each final word varied on the degree of relatedness to the preceding context, w ith some being highly related (BC), moderately related (R), or unrelated (U ) Younger subjects showed the expected N400 effect gradient (U > R > BC) in both the sentence and word-pair contexts, while older adults showed no dis crimination between the conditions (U = R = BC) for the sentence and limite d discrimination (U > BC) for the word pairs. These results support the inh ibition-deficit hypothesis, whereby older adults fail to inhibit related it ems in working memory, and suggest that older adults do not benefit from th e constraints of a sentence context. (C) 2000 Academic Press.