One of issues evident in this week’s readings was the concept of visual rhetoric as a function of the knowledge a viewer already has. In “Visualizations and Historic Arguments”, Theibault summarized this concern succinctly: “…authors have to consider how much background information the readers bring to the visualization…complex visualizations has increased the gaps between expert and novice interpreters, which raises challenges for historians who seek the most effective visual approach”. This struck me as a particularly important consideration from the stand point of public history, which frequently has the opportunity to engage an audience with very diverse backgrounds and levels of education.
Familiarity with the theory and methods of scholarly inquiry and interpretation, and the assumptions that are made in the construction of a visualization, is much less relevant to the tourist playing with the light up map of the Freedom Trail in the Old State House or following a time line of Midde Eastern history in the Museum of Science’s Dead Sea Scroll exhibit. To this public, Johanna Drucker’s visualizations of temporality exceed casual understanding, even as they reflect important considerations regarding the interpretation and use of qualitative concepts in visualizations as a scholarly activity. Martyn Jessop notes this disparity: “years of school life, and many of adulthood, are spent mastering written language but the western education system places little effort, or value on, teaching visual literacy” (288). Jessop is also understanding visualizations as a scholarly activity, but his treatment is more inclusive due his broadly stated purpose (“discovery of new knowledge” (282)) and use (if it generates insights (287)), and this has more purchase in public history. At this point, in visual literacy, Drucker’s visualizations require substantial explanation, relating to another concept introduced by Tufte when he discusses “Layers and Separation”, “confusion and clutter are failures of design, not attributes of information” (53).
Also for use in public history, a viewer’s background factors into creating effective visualizations by appealing to a customized experience. In describing the use of courtroom graphics, Tufte acknowledges their appeal to a jury: “visual displays of information encourage a diversity of individual viewer styles and rates of editing, personalizing, reasoning, and understanding …simultaneously a wideband and a perceiver-controllable channel”(31). I like the courtroom scenario for the treatment of an audience, because there is no doubt regarding what the lawyer is trying to do. There is clearly a visual rhetoric intent on persuading the jury to a particular point of view and in order to appeal to the jury, the lowest common denominator of visual understanding has to be constructed. The “perceiver-controllable channel” is a method of achieving this commonality between diverse individuals, which is a guiding principle that could definitely be used to develop visualizations for public history.