Also called “how to do it” knowledge. The knowledge of which operators to perform to move from a known start state to a desired state in a problem space.
A mental representation of a problem, including the start state, the goal state, and the operators or moves that allow transitions between states. According to Newell and Simon’s (1972) theory of problem solving, humans solve problems by constructing and searching a problem space.
Searching through a problem space from a known start state to a desired end state, or one of a set of desired end states, applying operators of uncertain outcome to move from state to state. Problem solving typically refers to a path through the problem space that includes explorations of deadend paths and backing up to prior states. (see skilled behavior for a contrasting type of behavior)
Problem Behavior Graph
A graphical depiction of search through a problem space.
A model that allows metrics of human performance to be determined analytically without undertaking time-consuming and resource-intensive experiments.
The rapid detection of visual features theorized to occur in parallel before the operation of selective attention.
When being trained as a carpenter or a nurse, for example, one shares a practice. At the same time, each individual who possesses a practice keeps it up and changes it as well. It is practice that allows us to talk about more than just individual skills, knowledge, and judgment, and not just about a “generic” human being. Practice is shaped historically, which is of particular relevance for design and use of computer applications.
Something (a physical artifact, electronic record, or human memory) that explicitly or tacitly maintains the current position within a formal or informal process. See: http://www.hcibook.com/alan/topics/triggers/
An example of an abstract formal model—that is, one that is used to analyze a class of systems and usability problems rather than specifying a particular system. The PIE model was developed at York University in the mid-1980s and was one of the first steps in a new stream of formal method work in human-computer interaction (HCI) that began at that time. See: http://www.hcibook.com/alan/topics/formal/
Program Evaluation Review Technique, a methodology developed by the U.S. Navy in the 1950s to manage the Polaris submarine missile program. A similar methodology, the Critical Path Method (CPM), which was developed for project management in the private sector at about the same time, has become synonymous with PERT, so that the technique is known by any variation on the names: PERT, CPM, or PERT/CPM. These methods are used in cognitive modeling to depict the parallel operation of perceptual, cognitive, and motor operators, with resource allocation and information-flow constraints.