Item analyses of age relations on reasoning tests.

Analyses at the level of individual items were conducted on 11 data sets representing various combinations of participant samples and tests of reasoning. The magnitude of the relations between age and solution accuracy did not vary systematically across a wide range of item difficulty, although there was some evidence for independent age-related influences on the more difficult items. The results were tentatively interpreted as reflecting the operation of at least 2 types of age-related effects on tests of reasoning, 1 common to all items and 1 sensitive to the greater processing demands associated with more difficult items.