Diagrams
People
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Marie-Paule Daniele Sungll Kim |
Graphics, such as maps, diagrams, and charts, consist of elements in a spatial array. Both elements and spatial relations are used in cognitively compelling ways to suggest meanings (Tversky, 2001, 2002, in press). They have many uses: for long-term memory, to ease the burdens of short-term memory and information processing, for conveying information that is spatial or metaphorically spatial, for inferences, for collaboration, and for the generation of new ideas, especially in design. Experts/high ability are more adept at inferring functional information from structural diagrams (Suwa and Tversky, 1997; Heiser and Tversky, submitted). Structural diagrams can be enriched to convey functional information (Tversky, Zacks, Lee, and Heiser, 2000).
Effective visualizations conform to two principles:
Congruity: structure and content of visualization should match structure and content of desired representation.
Apprehension: structure and content of visualization should be readily perceived and comprehended.
Animations violate the apprehension principle as they are typically too complex and too fast. They also violate the congruity principle as continuous events are normally understood as sequences of discrete steps. These may be the reasons why animated graphics typically fail to instruct better than informationally comparable still graphics (Tversky, Morrison, and Betrancourt, 2002).
Diagrams are key to effective collaborative problem-solving as they allow efficient establishment of common ground and efficient problem solving via gestures on diagrams (Heiser, Tversky, and Silverman, 2004).
A collaboration with computer graphics has led to development of cognitive design principles for effective visualizations and their implementation in computer algorithms that generate visualizations on demand (Agrawala, Phan, Heiser, Haymaker, Heiser, Phan, Klingner, Hanrahan, and Tversky, 2003; Agrawala, Tversky, and Hanrahan, 2004).