We've seen that associative approaches dominated early thinking about memory, but that growing problems with this approach convinced most theorists that memory was not based simply on the formation of associations; other processes would have to be considered. The Atkinson–Shiffrin model provided a preliminary framework for understanding these processes, but the research it spawned gradually led to important changes. In this chapter and the following one, we'll look at some of the most important changes. We'll begin here by focusing on how sensory input is coded – that is, what happens from the time we receive sensory input to the time a representation of that input is stored in long-term memory. Then, in Chapter 10, we'll consider what happens to material once it reaches that long-term store.

Sensory memory

We have described the Atkinson–Shiffrin model as a two-store model, but they actually postulated three stores. When we perceive the written word cat, for example, extensive processing must occur before we recognize the lines on the page as representing this word, and Atkinson and Shiffrin suggested that during this preliminary processing material is held in a temporary store that they called sensory memory. In this section, we will outline the early stages in sensory processing and discuss the role of sensory memory in facilitating this processing.