Speakers frequently ask me about what to wear for their big day. My advice is always the same. Now, a study has come along from Abraham Rutchick, a professor of psychology at California State University, that adds a new wrinkle.

First, there are the basic ideas I recommend that haven’t changed.

Number one, dress a little better than the audience.

You are the temporary authority as the speaker. Your clothes need to maintain that sense of authority. If the audience is business casual, and you show up in shorts and an Hawaiian shirt, you’re going to look like you crashed the party, not like the speaker. So don’t make that mistake. Do your research, find out what everyone in the audience will be wearing, and go one better.

Our first impression of you, the speaker, is visual, and so it’s doubly important that the first impression fulfill the audience’s expectations of a good thing coming, and the idea that there’s an expert in the house. Don’t dress like Dumb and Dumberer. You’re there to delight and instruct the audience, not to pander or disappoint them.

Note that I say “a little better” than your audience. If you’re talking on the west coast to a group of entrepreneurs in jeans and sneakers, showing up in a three-piece suit and tie is going to suggest that you’re hopelessly old-fashioned and out of touch to that audience. So dress it down a little, or add wacky socks, or something, to show that you’re not 150 years old.

Second, dress to fulfill your brand.

This bit of advice is trickier to follow, but just as important. Clothing represents you not only as an authority, but also as a unique brand. If you say, for example, that you’re an expert on creativity, but you show up dressed in the bland gray suit of a banker, you’re suggesting that your creativity is going to be on the bland side. Not good.

So spend some time thinking about how you can express your brand in some unique way in your clothing without breaking rule number one. If you’re an expert surfer, and you’re talking to New York bankers about the application of surfing insights to international finance, then you’ve got to find some way to express the surfing vibe within the context of a suit and maybe even a tie. That’s a challenge.

I’m speaking mainly from a male point of view here, but the issues for women are even more complicated because the options are so much more varied. That does give you, however, more ways to express your individual brand. So there are some advantages to being a woman in the still male-dominated speaking world!

Third, dress to kill.

My final bit of usual advice is to go high-quality and even expensive – you should feel and look great in what you’re wearing. The confidence that nice clothing imparts will give you a boost on the stage. Make sure it fits well and you can move in it. I’ve seen too many men and women wear suits that don’t allow them to raise their arms, for example, because they’re too tight-fitting. The result is awkward (and less authoritative) moving around the stage.

Finally, the results of the study. “Putting on formal clothes makes us feel powerful, and that changes the basic way we see the world,” says Professor Rutchick, and I love the insight because of the importance for a speaker of not only showing up strong, but feeling that way too. And, apparently, wearing more formal clothing helps people think more broadly and holistically, rather than too mired in the details. That can only be good for a public speaker.

I had to apply all this advice to myself recently when I did the filming for our new online course on public speaking. What was I to wear to show up on your computer screen in one or two-minute videos? I didn’t want to be too formal, because the little screen is inherently casual and I wanted to be able to connect. And yet, I’m the authority, the teacher, for the course, so I had to be authoritative enough.

A dilemma. I decided in the end to go with the jacket without the tie. You can be the judge of whether or not I succeeded, but now you know what I had to think about while getting ready!

So put on the glad rags when you get ready to speak. Dressing up will help both you and the audience accept you as the star of the show.