Experimental evidence for differential slowing in the lexical and nonlexical domains

Older and younger adults were tested on lexical and nonlexical tasks. When lexical and nonlexical processing were compared across equivalent ranges of task complexity, the degree of age-related slowing in the nonlexical domain was much larger than that observed in the lexical domain. To determine whether this nonlexical disadvantage is specific to older adults or whether it is characteristic of any slow individual, subgroups of fast older and slow young adults were matched on lexical processing speed. Older adults who were fast processors of lexical information were much slower at processing nonlexical information, but this was not true of slow young adults for whom the speed of processing lexical and nonlexical information was equivalent.