Two psychological refractory period (PRP) experiments were conducted to examine overlapping processing in younger and older adults. A shape discrimination task (triangle or rectangle) for Task 1 (T 1 ) and a lexical-decision task (word or nonword) for Task 2 (T 2 ) were used. PRP effects, response time for T 2 increasing as stimulus onset synchrony (SOA) decreased, were obtained for both age groups. The effect of word frequency on T 2 was smaller at the short SOA than at the long SOA,

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... slack effects, which were larger for older than younger adults in both experiments. These results suggest that older adults can perform lexical access of T 2 in parallel with the processing of T 1 at least as efficiently as younger adults.