In recent research, two qualitatively different classes of mental operations have been identified. The performance of one type of cognitive task requires attention, in the sense of mental effort, for its execution, while the second type can be performed automatically, independent of attentional control. Further research has shown that automatic cognitive operations can be performed without attentional control when three criteria are met: an independence of performance and processing load; the presence of benefit without cost in the use of advance information; and the lack of an instructions effect. Research gerontologists have proposed that deficits in effortful processing occur during normal human aging, whereas the efficiency of automatic processes remains relatively constant over age. However, relatively little evidence has been found to support this theory. In tasks that are not affected by instructions, such as judgments regarding frequency of occurrence, age differences are reported in some experiments but not in others. In experiments that have examined age differences in visual search and the use of advance information, the criteria for identifying performance as automatic have not been met. As a result, it is too early to add developmental invariance as an additional criterion for automaticity. (BL)