In a 2004 study, Elizabeth Sillence and her colleagues found that when it comes to evaluating health websites, the factors that caused people to distrust a website related primarily to the visual appeal of the website, including: busy layout, lack of navigational aids, boring colors, small print, and too much text. The factors that caused people to trust a website, on the other hand, were primarily related to the content of the website, i.e., whether it presented informative, relevant, unbiased, audience-specific information in clear, simple language.
While these findings were generated in a web design context, they’re also quite relevant to presentation design. Just as there is a two-stage process for evaluating whether to trust a website (in which websites are eliminated based on design before they are chosen based on content), there is also a two-stage process for evaluating whether to trust a speaker. Even if you have the best content in the world, if your delivery and visual aids aren’t up to snuff, these factors can cause the audience to immediately distrust you and disregard your message before they’ve even heard it. As always, it’s not enough to have good ideas—you also need to know how to present them effectively.