Isolating the age deficit in speeded performance.

The 'locus' of the age-associated behavioral slowing was investigated with Sternberg's additive-factor method of identifying information processing stages. The factor of adult age was found to interact with manipulations assumed to influence stages concerned with stimulus encoding, internal comparison, and response preparation or execution. Since age appeared to affect each stage of information processing, it was suggested that the age-associated slowing phenomenon is general rather than specific.