A new model of Graph and Visualization Usage

We propose that current models of graph comprehension do not adequately capture how people use graphs and complex visualizations. Toinvestigate this hypothesis, we examined 3 sessions of scientists using an in vivo methodology. We found that in order to obtain information from their graphs, scientists not only read o# information directly from their visualizations (as current theories predict), but they also used a great deal of mental imagery (which we call spatial transformations). We propos