Age differences were examined in 18 young and 18 older adults in perfo
rmance for a sequential letter-matching task in which stimulus onset a
synchrony (SOA) was varied from 0.2 s to 7.5 s (0.2, 0.5, 1, 2, 5, and
7.5 s). The same-different matching task used Posner's Task (Posner &
Mitchell, 1967), where both physical identity (e.g., A-A) and nominal
identity matches (e.g., A-a) are considered same stimuli and where le
tters with different identities (e.g., A-B; A-b) are considered differ
ent. Results indicated that older adults were slower and made more err
ors than young adults did. Young and older adults both made more error
s and responded more slowly at longer SOAs than at shorter SOAs. An Ag
e x SOA interaction showed older adults' latencies to be more adversel
y affected than those of young adults by the longer SOAs. Letter-match
condition affected performance, but neither age nor SOA interacted wi
th type of letter match. These results suggest an age-related deficit
in speed of delayed letter matching, where older adults have more diff
iculty than young adults in maintaining and/or retrieving information
necessary to make a delayed letter match.