Hierarchical Control of Cognitive Processes

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Many studies have shown that novice performers in demanding tasks (e.g., driving, carpentry, typing) are conscious of each step, attending to the details one by one. On the other hand, skilled performers are only conscious of high-level goals, leaving the details to lower-level processes (hierarchical control). These studies leave an important question unanswered: How does this hierarchical control emerge with practice? How do experts develop lower-level control processes that take care of the details? The proposed research focuses on skilled typewriting, where associative learning causes all the keystrokes in a word to be activated in the motor system at the same time, so the motor system must decide when to make each keystroke. Novice typists activate one keystroke at a time, using higher-level processes to control serial order. As typists acquire skill, words are associated with each of their constituent keystrokes, so the presentation of a word activates all of its keystrokes at once, forcing the motor system to control serial order. This creates a lower-level control process that produces keystrokes, which is distinct from the higher-level control process that produces words to be typed, resulting in hierarchical control. The proposed research will test this proposition in four projects in which the investigators will present typists with novel types of keyboards and tasks, and examine learning over many sessions. They will measure the emergence of hierarchical control in terms of parallel activation and the conscious awareness of the details of the task. The project will have an important impact on basic and applied research. Typing has now become a ubiquitous activity in modern life, and understanding the science behind the skill will have a broad impact on education as our workforce ramps up for the 21st century. The proposed research may also provide new criteria for evaluating successful training in other areas requiring expertise, going beyond simple tests of speed and accuracy to more sophisticated tests for the emergence of hierarchical control. More generally, the projects will promote new connections between research on cognitive control and research on motor control, since both are required in typewriting.