After all those principles, here’s a look at an arguably lighter issue:  speaker hairstyles.

Here’s the problem for the modern keynote speaker.  You’re most likely going to be beamed onto a giant IMAG screen, often two of them, on either side of you standing there on the stage.  You may actually be overwhelmed visually by a closeup of your face, or a head-and-shoulders shot of you magnified from your usual size to thirty feet high.

In High Definition. 

That means that your makeup, grooming, and hairstyle matters.

What should you do?  Fortunately, science comes to the rescue.  A delightful study recently found that hairstyles signal to others how smart, professional, and sexy we are.  So it’s just a matter of picking the right style to maximize your stage presence, right?

If only it were that simple.  Here’s the rest of the problem.  It’s different for men and women, but difficult for them both.

Medium-length, casual-looking styles make women look more intelligent, and more good-natured.  That’s good, right?

Well, yes, except that shorter, highlighted hairstyles make women look more outgoing and confident.

So you have a choice – intelligent and nice or outgoing and confident.

For men, medium-length, side-parted hair makes you look the most intelligent.  Phew.  I don’t have to change my do.

But there’s bad news here to:  that kind of hair makes you look narrow-minded.   Who me?

And something to avoid:  long hair makes men look good-natured, but less intelligent.

So it’s your call – pick your effect, style your hair accordingly, and get ready to test perceptions at twenty or thirty times your natural size.

And what about the rest of you?  What should you wear?  I’ve posted twice on this important subject earlier this year, here and here, but here’s a quick refresh:

1.Always dress as well or slightly better than the audience.  If you show up at a Silicon Valley start up dressed like a banker in the full regalia, suit, tie, and etc, you will be written off by that audience as a hopeless case.  The chance that you will connect with them becomes vanishingly small.  So you want to dress as well as the audience, or slightly better, but the emphasis is on slightly.  You don’t want a big mismatch.  If you dress worse than the audience, of course, you’ll simply look like you shouldn’t be there.

2.Dress consistently with your brand.  This one is tricky, because there are times when that entrepreneur may want to put on the suit and tie – such as when you’re meeting with a banker.  But to the extent that you can, you should dress to mirror your brand, or embody it.  I’ve seen wildly uncomfortable entrepreneurs in an ill-fitting suit and tie who would have looked better in something closer to their normal garb.  So if you’re a creative type, wear something that signals that.  If you’re a boring banker, then wear the gray suit.  If you’re a creative banker, please wear a little sign that says, “Don’t invest with me,” so that I can see you coming.  Which leads me to my third rule….

3.Dress to feel like a million dollars.  Whatever costume you end up with, you should think about how it makes you feel.  If you feel great in a suit, or in a Versace dress with mile-high heels, then you should consider wearing that because if you feel confident, that will spill over into your presentation and your persona and you will present better.  But….

4.Dress in something that allows you to move.  A speaker needs to be able to move on stage, and some fashions restrict movement so severely that you’ll look ridiculous when you try to walk.  That won’t work.  You have to be able to get on and off – and around – the stage.

5.Dress like a grownup.  Unless you are 12.  Your costume needs to be appropriate to your age, ilk, and style.  Don’t try to dress like a hip teen if you’re over 30 and are talking to a high school audience.  The results will be tragic.  Act and dress your age.  What you wear signals your tribe; don’t try to join one through costume if you don’t really belong.

6.Dress strategically. Think about the audience.  What accessory can you wear, or slight change can you make, that will allow you to stand out from the crowd, without looking freakish?  A lot of Silicon Valley types wear suits (to show that they’re successful) but add brightly colored sneakers (to show that they’re still hip and rebellious).  The costume you wear sends a message; figure out what you want to say with your style.

My advice is that every speaker needs to create a minimum of three on-stage wardrobes, consistent with your brand and the other rules I’ve outlined.

First, The Full Fig.  This is your top-of-the-line outfit, appropriate for the meeting with your bankers, or talking to Really Important People at Davos or the Real TED.  It’s probably a suit or dress, but if it’s not, it should at least be – and look – expensive.

Second, The Upscale Casual.  This outfit will work for many a speech and conference that takes place in a resort location with an audience that will be dressed in a variety of styles, with an emphasis on the casual and comfortable.  It might be a sport coat, dress shirt no tie, and (expensive) jeans or trousers for the men, and the moral equivalent for women.  But be very careful.  I recently spoke to an IT group in Upscale Casual, and was astonished to find about half the audience wearing the Full Fig.  Were they all coming from job interviews?  I had to work twice as hard to establish my authority — my right to speak to them — at the outset.  Clearly, my sense of the IT crowd needs updating.

Third, The Among the People.  This is the outfit to wear when you’re going as native as you can, among the entrepreneurs, or the SXSW crowd, or any group that includes people who actually think about wearing Onesies outside.  The audience will be dressed in ripped jeans and t-shirts, so if you show up in a suit you’ll feel alien and the audience won’t listen to you.  You might wear expensive jeans, a casual shirt, and a sports coat or the moral equivalent.

The idea is that you are a temporary authority as a speaker and as such you need to signal that sartorially.  The audience will expect you to do so.  But if you show up wildly mismatched with the audience, communication will be difficult and your performance will not be judged on its merits.

All of this is terribly far from thinking great thoughts about your subject and changing the world with your speech.  But if you don’t get the hair and clothes right, no one will hear you.  So get to work.