Age and the allocation of attention across the time course of word recognition

Younger and older adults performed lexical decisions on ambiguous words, un ambiguous words, and pseudowords, and simultaneously responded to an audito ry probe presented at stimulus onset asynchronies (SOAs) of 90, 180, or 270 ms. For both age groups, lexical decisions and probe responses were faster for ambiguous words than for unambiguous words, and slowest for pseudoword s. For the older adults, but not the younger adults, lexical decisions were slower when the probe was presented (the dual-task condition), compared wi th a control condition in which the lexical decision was performed alone. T he older participants also showed slower tone-detection responses in the du al-task condition than when the tone was presented alone. For all participa nts, proportional tone-detection times (compared with tones in isolation) d ecreased with increasing SOA, but this decrease was less pronounced in the older group. Finally, the time between responses in the dual-task condition was longer for older than for younger adults. The results indicate that wo rd meaning influences the allocation of attention similarly for younger and older adults, but that older adults suffer a cost and become disproportion ately slower in processes related to response coordination and output.