A number of years ago, I was working with a colleague in eastern Oregon, and he insisted on wearing a cowboy hat and boots to public meetings with local landowners. He felt that by looking the part that he would gain credibility and trust with the locals. It backfired because he wasn’t being authentic – and he never gained their trust.
Authenticity is being “true to one's own personality, spirit, or character” (merriam-webster.com). When someone is authentic, we trust what they say to be true. When we sense that someone is withholding information, or that they are trying to mislead us in some way, alarms go off in our head and we become suspicious.
If you want an audience to believe what you are saying, be receptive to your ideas, trust your data, and accept your conclusions, then you must be wholly authentic. If you are using borrowed slides, mimicking a mannerism, or imitating a style of dress, then you are not being you and the audience will instinctively know. Because you are putting on a show, you will probably feel uncomfortable, and the audience will be uncomfortable as well. So the next time you are watching a really good speaker, or are sitting through a training course, keep asking yourself “that looks like a great idea, but will it work for me?” Try it on – how does it feel? As you experiment with new presentation styles and ideas, you will know which ones work for you because they will simply feel right – like your favorite pair of jeans.