This paper describes an experimental attempt to measure the impact on human performance of the relationship between a set of motor tasks and two different physical system interfaces. The surficial intent of the experiment was to determine the extent to which similarity of characteristics between vehicle control tasks and physical interfaces improved human performance. The deeper intent was to show that research in this area could derive results that may someday fit into a larger framework describing the general relationships between task characteristics and physical interface characteristics.
Three primary controlling elements are related to human task performance (Farina & Wheaton, 1971). The first concerns the traits and abilities of the system operator and includes items such as the user's age, manual dexterity, emotional mood, and training/experience. The second relates to attributes of the task to be performed and consists of items such as the number and duration of output units, rate of response, number of steps in the procedure, and oral/written instructions. The third is associated with the characteristics of the environment in which the user-system operates and includes factors such as temperature, humidity, and noise as well as interface hardware, software, and processing.
Fidelity Stimulus-Response Compatibility, and control-Display Compatibility
An environment that supports task-interface concordance should allow the user to complete that task more quickly and/or accurately. The concept of task-interface concordance is related to, but slightly different from, the concepts of fidelity, stimulus-response (S-R) compatibility, and control-display compatibility. The Handbook of Human Factors and Ergonomics (Salvendy, 1997), defines fidelity as the extent to which a training interface corresponds physically or functionally to an operational interface. S-R compatibility refers to "the degree of congruence in the pairings of the elements in a stimulus and response set" (Fitts & Deininger, 1954, p. 483). "Control-display compatibility" is referred to as "the congruence between control and display movements" (Worringham & Beringer, 1989, p. 387).
The term task-interface concordance, as used in this paper, is related to the three concepts just discussed but differs slightly from them. Whereas fidelity refers to the concordance between a test and an actual interface, S-R compatibility refers to the concordance between a stimulus and a response, control-display compatibility refers to the concordance between a control movement and a display movement, and task-interface concordance refers to the similarity between the control characteristics inherent in a task and those inherent in an interface.
The theory of cognitive fit, originally proposed by Vessey (1991), was based on a meta-research study of the "graphs versus tables" literature. It generally states that human performance is enhanced when there is a cognitive fit between a task and the strategies used by the decision maker. The term cognitive fit refers to the similarity between the mental strategies used by a decision maker and the method of data display. For example, if decision makers are tasked with identifying trends or patterns (a spatial task) in a data set, they will perform better if the relevant data is presented in spatial form, such as a graph. Conversely, if their task is to specify a particular numeric value (a symbolic task) from a data set, they will perform better if the relevant data is presented in symbolic form, such as a table of values.
From the perspective of industrial engineering, one experiment (Andre, Haskell, & Wickens, 1991) investigated the effects on human performance of orthogonal stimulus and response arrays. …