The information-processing approach uses a com­puter metaphor to explain how people process stimuli. Just as with a computer, information enters the system (people’s brains) and is transformed, coded, and stored in various ways. Information enters storage temporarily, as in a computer’s buffer, until it is sometimes stored more permanently, as on a computer disk. At a later time, information can be retrieved in response to some cue, such as a com­mand to retrieve a file. Let’s see how this works more formally.

The information-processing model is based on three assumptions (Neisser, 1976): (1) People are active participants in the process; (2) both quanti­tative (how much information is remembered) and qualitative (what kinds of information are remem­bered) aspects of performance can be examined;

and (3) information is processed through a series of processes. First, incoming information is trans­formed based on such things as what a person already knows about it. The more one knows, the more easily the information is incorporated. Second, researchers look for age differences in both how much information is processed and what types of information are remembered best under various conditions. Finally, researchers in adult development and aging focus on several specific aspects of information processing: early aspects, which include a very brief sensory memory and attention; and active processing, which transfers information into a longer term store (e. g., long­term memory).

Using the information-processing model poses three fundamental questions for adult development and aging: (1) Which areas of information process­ing show evidence of age differences (e. g., early stages of processing such as attention, working memory, long-term memory)? (2) How can we explain variability when we find age differences in information processing? (3) What are the practical implications of age-related changes in information processing?

In this chapter, we first focus on early aspects of processing, that is, attention. Then we consider dif­ferent domains of memory performance and how attentional systems influence memory. In doing so, we differentiate between short-term memory and working memory; processes involved in long­term memory, including implicit and explicit mem­ory; and episodic and semantic memory. Next, we address the reasons for age differences in these processes. Finally, we discuss the exciting new work on interventions to improve memory functioning similar to those described in Chapter 2. By the end of this chapter, we will have a relatively complete picture of how we have acquired, processed, stored, and will remember the information in this chapter.

Attentional and Perceptual Processing

All memories start as sensory stimuli—a song heard, a person seen, a hand felt. We need to experience these things for only a small fraction of a second
in order to process the information. This ability is due to the earliest step in information processing, sensory memory, where new, incoming information is first registered. Sensory memory takes in very large amounts of information very rapidly. It does not appear to have the limits that other processes do when attentional focus is applied. It is more like a very brief and almost identical representation of the stimuli that exists in the observable environ­ment. The representation exists in your mind in the absence of the stimuli itself.

However, unless we pay attention to sensory information, the representation will be lost very quickly. For example, try drawing either side of a U. S. penny in detail. (Those who are not from the United States can try drawing a common coin in their own country.) Most of us find this task difficult despite seeing the coins every day. Much detailed information about pennies has passed through our sensory memory repeatedly, but because we failed to pay attention, it was never processed to a longer lasting store. Age differences are not typically found in sensory memory (Poon & Fozard, 1980; Smith, 1975); however, they do begin to appear when attentional processes are applied to sensory memory.

As Joan McDowd and Raymond Shaw (2000) have maintained, attention and perceptual process­ing are best conceived from a functional perspective. Attention, for example, is composed of separable dimensions serving different functions. McDowd and Shaw note that the complex tasks we engage in when processing information usually require more than one attentional function. For example, in the case of Trey, he must selectively attend to or focus on the road and its obstacles while at the same time filtering out distracting information. In addition, attentional processes are influenced by the capacity to direct and sustain attention and the speed with which information is processed.

Concept Checks

1. What are the three assumptions underlying the information-processing approach?

2. What is the pattern of age differences in sensory memory?