Attention is the foundation of cognition. We use it to control everything we do: to focus perception, store information in and retrieve information from memory, make decisions, and direct action. A key to understanding attention is understanding its limitations. For a large class of the situations we face, the resources we have to deploy attention are limited – we can choose to attend to some things but not everything. When we start to learn how to drive, we can focus on steering, or braking, or accelerating, or the traffic in front of us, but not all at once. Yet practice and learning can cause such perceptions, decisions, and actions to become increasingly automatic, bypassing the initial limitations and allowing the implementation of ever-increasing expert behavior. The transition from resource-limited behavior to automaticity (also termed automatism), the processes involved in each, the mechanisms that produce learning, and a model framework in which to explain each of these were the foci of two articles we published back to back in Psychological Review in 1977. The titles were informative: Controlled and automatic human information processing: I. Detection, search, and attention; and II. Perceptual learning, automatic attending, and a general theory.

There are many ways attention is employed and assessed. To various degrees it can be focused narrowly, spread widely, maintained over time, and interrupted by distraction. All of these are made difficult because attentional capacity is highly limited, largely through its implementation in short-term memory, also called working memory. The short-term memory system has limited capacity. It can hold a limited amount of information, and can employ a limited number of processes that control cognition – not only attention, but also memory storage and retrieval (as discussed in the 1968 chapter by Atkinson and Shiffrin titled “Human memory: A proposed system and its control processes.”). It would be extremely difficult for us to operate in our daily lives if we had to employ limited attention to control all our activities. Thus, it is essential and fortunate that we have a means to overcome such limitations: Learning can produce automatic behavior that bypasses such cognitive limitations. Responses gradually come to be made by rote in response to consistently occurring environmental situations.