Cognitive Efficiency Considerations for Good Graphic Design
CARNEGIE-MELLON UNIV PITTSBURGH PA ARTIFICIAL INTELLIGENCE AND PSYCHOLOGY PROJECT
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Larkin and Simons 1987 analysis of how graphical representations support task performance is applied to designing graphical displays that streamlline information-processing tasks. Theoretically this streamlining is done by designing external data structures that a allow users to substitute less effortful visual operators for more effortful logical operators, and b reduce search for needed information. A design program called BOZ is used to produce four alternative displays of airline schedule information to support an airline reservation task. We postulate several procedures that use a set of visual operators to perform the task using the different graphics. The number of times each operator is executed provides one measure of task difficulty for a procedure and graphic. A second measure is the difficulty of executing each operator. Seven subjects performed the airline reservation task using each of the four graphics. Response times for the different graphics differ by a factor of two, and this difference is statistically highly significant. Detailed data analyses suggest that these differences arise through substitution of visual operators for logical ones and through the use of visual cues that help reduce search. The analyses provide quantitative estimates of the time saved through operator substitutions.