Hierarchical control of cognitive processes

Vanderbilt University, Nashville TN

Investigators

Abstract

Psychologist Gordon Logan at Vanderbilt University will use the deceptively simple task of typing to study "cognitive control," that is, how we plan and execute complex actions. Skilled typists appear to effortlessly use an external script (when copying) or an internally generated plan (when composing) to choose the appropriate movement in the form of a key-press 5-6 times per second. However, in a recent experiment, Logan showed that despite such virtuosity, skilled typists do not even know which hand they are using to depress a key at any given moment. The demonstration is clever and simple: try typing a sentence using only your left hand and typing only those letters normally typed with the left hand. Not surprisingly, this instruction slows people down, but it also renders them greatly less accurate (5-6 times more errors are produced), indicating that skilled typists are simply not aware of what they are doing at the most basic level. Logan's theory of cognitive control as applied to typing assumes that proficient typing is the result of the coordination between two "nested feedback loops." The "outer" loop determines the sequence of words to be typed and the "inner" loop translates the words into the appropriate keystrokes. This explains the paradox that skilled typists are not aware of something as basic as which hand they are using: the inner loop automatically and effortlessly determines the sequence of key presses needed to produce the sequence of words planned by the outer loop, but the outer loop does not know or care how the inner loop performs its separate task. This project will examine three aspects of this double-loop model of cognitive control: awareness (how much does the outer loop know about what the inner loop is doing?), structure (do words or some other level of organization, such as letters or phrases, serve as the interface between the two loops?), and feedback (the outer loop is hypothesized to rely on visual feedback while the inner loop is hypothesized to rely on kinesthetic feedback). A better understanding of the mechanisms of cognitive control could lead to improvements in the way complex skills are taught and practiced. In the domain of typing, a detailed understanding of the process could have implications for the design of keyboards and other text-input devices. With the proliferation of computers in modern culture, typewriting is an essential skill in the workplace, in schools and universities, and in leisure activities. This project will also have an important impact on the broader literature on cognitive control, which is embroiled in a controversy over hierarchical processing. The outer-loop inner-loop theory provides a new perspective on research on automatic and controlled cognitive processes, which are often regarded as opposites. This project shifts the research focus from whether processes are controlled to how processes are controlled.