Notes from 55th International STC Conference
Philadelphia, Pennsylvania, June 1-4, 2008

The Structure of PowerPoint Presentations:
The Art of Grasping Things Whole

Alan Gross

Gross is a professor at the University of Minnesota. His research has centered around three areas: scientific communication, rhetorical theory and, most recently, visual communication. Currently, he is completing a manuscript on scientific communication, in the midst of a book on Juergen Habermas, viewed from a rhetorical prospective, and putting the finishing touches on a prospectus for a book on visual communication in the sciences.

Session Description: This presentation showed how famed technical illustrator Edward Tufte is right most of the time, but not all of the time. Drawing upon Jean Luc Doumont’s guidelines for individual charts and for presentations (cross-link to previous conference), the presenter showed and analyzed two PowerPoint lectures by good scientists who are also good communicators. Both concern the eruption of Mount St. Helens – one for a general audience, one for an audience of professional volcanologists. He showed how both presenters applied Doumont’s guidelines but also how each made judicious exceptions to tailor their presentations to their respective audiences.

• Tufte: How is that each elaborate architecture of thought always fits exactly on one slide? The rigid slide-by-slide hierarchies, indifferent to content, slice and dice the evidence into arbitrary compartments, producing an anti-narrative with choppy continuity.
• What does Tufte’s criticism imply?
• The focus should not be only on the individual slide.
• The focus should also be on whether that slides furthers the overall messages of the presentation
• We’ll look at two treatments of the same event (eruption of Mount St. Helens)
   
• A narrative in the case of general audiences
• An argument in the case of professional audiences
• When does an individual slide further the presentation as a whole?
• According to Jacques Bertin, graphs are well constructed if we can grasp their point in a single image.
• By analogy, slides are well constructed if we grasp each as a single thought, while at the same time, we grasp their relationship to a narrative and an overall message.
• We can accomplish this task if we follow Doumont’s guidelines
• His guidelines for individual slides
   
• Clear message supported by visual evidence
• As little text as possible
• Headlines not more than 2 lines
• Full sentences with subjects and verbs
• No distractions
• Ruthless self-editing.
• Are deviations from Doumont’s guidelines permissible? By all means.
   
• Remember: “The letter killeth but the spirit giveth life.”
• No deviation is justified if your audience cannot grasp the slide in a single thought (gestalt).
• Presenter provided examples of justifiable deviations from Doumont’s guidelines (where the spirit of a single, gestalt impact is still preserved)
• He then provided examples of non-justifiable deviations, with recommended fixes
• Doumont’s guidelines for whole presentations
   
• Adapt to your audience
• Integrate verbal/visual elements
• Maximize “signal,” minimize “noise” (eschew what Tufte terms “chartjunk”)
• Employ effective redundancy
• Gave two applications, both on Mt. St. Helens
   
• One for general public (Dzurisin)
• One for volcanologists (Iverson)
• General audience
   
• Narrative is the organizational choice.
• Presenter applied a story grammar to The Little Engine and then to a dramatic narrative of the Mount St. Helen’s eruption, for the general public
• Professional audience (volcanologists)
   
• The presenter developed an argument for a particular form of volcanic activity. He used an abductive argument... Charles Abners Peirce
• An act of insight
• The different elements of the hypothesis were in our minds before
• But the concept was never before put together before into a new suggestion before our contemplations
• Iverson’s model:
   
• Act of insight
• Scattered facts
• No way of putting them together
• A new explanation of why and how the eruption took place.
• After the abductive leap, he now deduces sets of empirical consequences
• Iverson followed Doumont’s guidelines for whole presentations... difference is that he makes redundancy crucial as a way of keeping the audience on track.
• Many adults can follow only the simplest arguments: Aristotle’s Rhetoric
• The problem lies in the difference between implication and inference (Euclid’s Model)
• Deduction confirmed the plausibility of the mechanical model that abduction has created, tying together science and math
• Conclusions
   
• Dzurisin relies on a story grammar to optimize this audience’s ability to follow his narrative
• Iverson relies on a logical structure to optimize his audience’s ability to follow his argument, to integrate the verbal and visual, to maximize signal and minimize noise, using redundancy to keep the logical in the forefront
• In PowerPoint, the crucial variable is the extent to which slides are integrated into whole presentations
• For general audiences that integration is achieved through the structure that narration imposes
• For professional audiences, that integration is achieved through the structure that argument imposes
• To realize these goals, presenters should still follow Doumont’s guidelines: to the letter if possible, to the spirit regardless

Contact: grossalang@aol.com: Will provide presentation and paper upon request.