The mismatch negativity (MMN) of the event-related (brain) potential (ERP)
has been shown to reflect the storage of information in sensory memory and
is thought to reflect the operation of a mechanism that compares frequently
occurring standard with infrequently occurring deviant acoustic events. Th
e MMN was recorded from young (mean = 23 years) and elderly (mean = 72. yea
rs) adults to small (50 Hz) and large (300 Hz) frequency deviants and to a
variety of novel, environmental sounds. At each level of deviance, MMN ampl
itude was smaller in the ERPs of older relative to younger adults. Young, b
ut not older adults showed robust MMNs at the smallest level of deviance. M
oreover, a P3 component was observed in the ERPs of the young to both large
tonal and novel deviants, whereas a robust P3 component was evident only t
o the novel deviants in the ERPs of the old. The data suggest that older ad
ults demonstrate less sensitivity to stimulus deviance and that only highly
deviant events are likely to involuntarily capture their attention. (C) 19
98 Elsevier Science Inc.