New research shows that formal business attire—suits for men and the equivalent for women—increases your ability to think big, abstract and creative ideas.
All of those are good for speakers, so suit up.
Be consistent, of course, with several other important aspects of dress: Dress better than the audience (but not too much better), and ensure your clothes are relevant to your talk.
For example, if you’re at an entrepreneurs’ conference in Silicon Valley and everyone is dressed in T-shirts and jeans, you might wear a sports coat. A suit would probably be overkill. Bankers, on the other hand, will expect you to wear a suit and a tie.
We negotiate better in suits than in casual clothing. If you’re undertaking significant audience interaction, keep in mind that dressing up empowers you in several ways.
If you’re speaking about creativity, however, a suit could indicate that you’re not a creative type. In that case, balance formal attire with the iconic statement you’re trying to make. Think of Steve Jobs’ black turtleneck and jeans. He was signaling that he was different from the typical corporate executive, and it worked well for him.