A draft chapter on Corrupt Techniques is currently available online, in which he discusses several modes of presenting misleading or corrupt evidence.
|Effects without causes||Beware of presenters using the passive voice or bullet lists.|
|Cherry-picking||Presenters pick and choose, select and reveal only the evidence that advances their favored point of view.|
|Punning||Puns enable over-reaching, as sharply focused ideas tend to sprawl, grow mushy and collapse into vague metaphors when applied to content outside their original domain.|
|Chartjunk||Chartjunk develops from the premise that audience can be charmed, manipulated or fooled by means of content-free misdirection: garish colors, generic decoration, phoney dimensionality, corny clip-art.|
There is nothing wrong with trying to persuade people - within a framework of trust and mutual respect. Corrupt persuasion is an abuse of trust.
Corrupt persuasion also carries a metacommunication, for those able to pick it up. Tufte writes: "For consumers of presentations, gratuitous and cartoonish decoration of statistical graphics has the redeeming virtue of providing insight into the presenter's integrity and analytical skills: no integrity, no analytical skills." In other words, it ain't what you say, it's the way that you say it.
Update (August 2005): See also review by Graham Shevlin of Tufte's essay The Cognitive Style of PowerPoint.
Related Posts: The PowerPoint Collection