There was a great New York Times piece on Jerry Seinfeld last month. You should read it. Here are some of his musings:
I had a joke: “Marriage is a bit of a chess game, except the board is made of flowing water and the pieces are made of smoke.” This is a good joke, I love it, I’ve spent years on it. There’s a little hitch: “The board is made of flowing water.” I’d always lose the audience there. “Flowing water? What does he mean?” And repeating “made of” was hurting things. So how can I say “the board is made of flowing water” without saying “made of”? …
The breakthrough was doing this (Seinfeld traced a square in the air with his fingers, drawing the board). Now I can just say, “The board is flowing water,” and do this, and they get it. A board that was made of flowing water was too much data. Here, I’m doing some of the work for you.
So what does Jerry Seinfeld have to do with PowerPoint?
Properly used, PowerPoint can convey meaning. It can shorten your spoken words, making them more powerful and easy on your audience. And you can let your slides do some of the work.
Notice that Jerry didn’t put his spoken line into his visual. That would be redundant. And it would confuse his audience trying to comprehend spoken words and reading simultaneously. Nor should your spoken words be in your slides.
A picture says a thousand words. Don’t make your audience read them.