Effects of varying irrelevant information on adult age differences in problem solving.

Sixty young (M = 20.6), middle-aged (M = 52.4), and elderly (M = 72.6) men and women solved problems which required them to match one of two stimulus arrays to a standard. On each problem one dimension (color, form, number, or position) was relevant to correct matching, and three dimensions, which were either variable or constant, were irrelevant to solution. Age and the number of variable irrelevant dimensions were the best predictors of reaction time and error scores. Young were significantly faster than middle-aged and the middle-aged were faster than the elderly. The elderly made most errors, but the young and middle-aged were not significantly different from each other. Reaction times and errors increased as the number of variable irrelevant dimensions increased. For the elderly there was a disproportionate increase in both reaction times and errors as levels of irrelevancy increased. No reliable differences were found with regard to gender. The results were discussed in terms of an age-related decline in the ability to ignore irrelevant information.