Background: While laboratory tests indicate that older adults typically perform more poorly than do younger adults on many types of memory tasks, the question arises as to whether, or to what extent, it is valid to attribute these differences to ageing per se or to some variable or class of variables that intervene between age and remembering.
Objective: The purpose of this review is to present three current views that might explain the relationship between age and remembering. They can be construed as variants on resource theories and include: the processing speed hypothesis, the executive function hypothesis, and the common cause hypothesis.
Methods: The review samples results pertinent to these hypotheses that derive from behavioural research. Studies involving various imaging techniques were considered beyond the scope of the review.
Results: The balance of research strongly implicates reductions in the speed of information processing as a fundamental contributor to normal age-related memory loss. Nonetheless there are circumstances where other mechanisms, such as working memory, executive function, and sensory processes, are important.
Conclusion: Despite the phenomenological and empirical reality of age-related memory loss and the breadth of attempts to explain it, much work remains to be done to understand why it occurs. Contemporary debates about the nature and means of identifying shared and unique effects promise to shape future directions for research on memory aging.