The goal of the present chapter is truly introductory. In it, I attempt to provide a theoretical context for the chapters that follow and to raise some general issues. The chapter first outlines a “modal model” of human information processing, particularly that related to memory and language. It then assesses weak and strong contributions that the information-processing approach could make to research on aging.

The modal model

Some 20 years ago, Murdock (1967) used the term “modal model” to describe the then dominant two-store conception of human memory. An important assumption of this model was that there existed two discrete functional units in the memory system, one for active storage and rehearsal of a limited amount of information (short-term memory), the other a more temporally extended, capacious repository of knowledge (long-term memory). This modal model has come under intensive fire, both for its limited perspective on what memory is, and for its rigid partitioning of the memory system. Nonetheless, the fundamental distinction of the model has persisted, in various forms.

In general, human information-processing theory provides two types of description: Structural descriptions pertain to the data stored in memory – both the functional components in which they reside, and the nature of the data themselves. Processing descriptions pertain to the use of those data – the states they may enter and the transitions between different data representations and stores. Any account of a behavioral phenomenon in information-processing terms must make assumptions about both structures and processes.