As in every other realm of public speaking, most of the rules around what to wear depend on context: what sort of speaker are you, and in what sort of environment? If you are a man, then you may want to consider whether a tie is right or wrong for a particular platform; if you are a woman, the appropriate length of your skirt and the height of your heels may be an open question.
Your body language is not only made up of what you do on stage, it also includes what you wear. In just the same way that you should speak in a tone and style that is natural to you, your dress should reflect who you are. If you are comfortable and authentic in all aspects of your delivery, that will communicate confidence and authority to your audience – key impressions to make when you are asking them to listen, and learn, from you.
So the crucial question to ask when dressing for your presentation is: what is the right impression to make in this environment? You must ask yourself both about your own preferences and the audience’s expectations. Wearing a suit and tie in Silicon Valley won’t wash; but jeans and a t-shirt in the City of London will not win your presentation any converts, either.
Of course, in any context what you do not want is for the audience to be paying more attention to your dress-sense than your words. That means that in a conservative setting you should choose sober shades of blue and grey for your suit, and that even in a casual setting loud designs or fluorescent colours are still a no-no. Audience research shows that blue and grey are colours that generate a feeling of respect; bright orange is the most untrusted colour – so, if you wear that colour, statistically the audience are more likely to think you are a buffoon. Imagine your dress as the backdrop against which your speech will be given.
Dressing as your audience dresses, and doing so in a way that will draw attention to what you are saying, will enhance your credibility – and this will encourage your audience to put more store against what you are saying. It also demonstrates a respect for your audience, signifying that you have done your research and both understand their environment and share its values.
A good recent example of how dressing for public speaking can go badly wrong is the infamous shirt worn by scientist Matt Taylor to announce Rosetta probe’s successful comet landing. His brightly-coloured, noisy design featured scantily-clad women, caused an internet storm and no one heard anything Taylor said, despite the huge achievement the Rosetta Project had just enjoyed.
So dressing appropriately is absolutely crucial to the success of your speech. You must be comfortable in your clothes, of course, and there are often some practical considerations – if you’ll be wearing a microphone, where will it be clipped? Microphones come with a battery pack, too, so for women without a belt a jacket can be a good way to conceal a pack clipped to a dress; for men, clipping the pack to a belt rather than a waistband will look best.
Wear something you will feel good in, and dress for the environment. You want people to hear your words, not that loud pattern.