Public speaking means – for most people – stress and a sudden flurry of decision-making under stress. The conference organizer tells you the audience is larger – or smaller – than expected. How should you adjust? The MC suddenly informs you that they’re running late, and it would be great if you could get your talk done in 30 minutes instead of 60. Do you adjust or insist on your full hour? You walk out to the podium and find that the stage people have put a plant in the way of half your sight lines. How do you work around the new vegetation?

And then, even more critically, there are the thousand little adjustments that you’ll need to make as you actually give your presentation. Are you pausing enough? Is the audience getting what you’re saying? Are they zoning out – would it be a good time to take a few questions in order to take the temperature of the assembled folks? And remember to wait for that joke – it always works. Whoops – they didn’t laugh. How to cover than one?

And on and on. One of the less heralded aspects of public speaking is that it involves non-stop decision-making in the moment on the day, as well as a series of less pressured decisions running up to the actual event.

As a speaker, I’ve felt that pressure. And as a coach, I’ve seen it affect speakers over the years in a variety of ways. Some people seem to do better under stress, of course, and some do worse – but is there any pattern to it? Is it all individual variation, or are there some general rules we can find that will help us navigate the treacherous terrain of public speaking decisions?

With these questions in mind, I was particularly interested to find a study that addressed decision-making under stress. Stress turns out to affect us in counter-intuitive ways. It’s not what you’d expect, and the insight contains a useful lesson for public speakers.

What the study found was that we tend to become more optimistic in our decision-making under stress. The gambler that bets it all. The politician that agrees to an unenforceable agreement. The public speaker that decides to do something dumb that he imagines will work beautifully!

What happens is that, like teenagers, we focus more on the positive aspects of the imagined outcome than the negative. We get unrealistically enthusiastic, in other words. We learn more from positive feedback than negative. We ignore the negative aspects of a choice in favor of the positive.

When I saw this study, something clicked. I was suddenly reminded of a pattern of behavior I have seen over and over again in my speakers – the tendency to make a last-minute change to the script, or some aspect of the presentation – imagining that the outcome will be vastly better.

My reaction has always been alarmed (at least to myself) because I know the benefits of putting on the show that you’ve rehearsed, and the dangers of last-minute changes that you don’t have time to adequately take on board.

My experience is that those last-minute changes produce minimal improvements at maximum risk to all concerned. It’s far better to rehearse the presentation you thought was good a week ago, and deliver it with confidence, than it is to wing it at the last minute with an ill-digested, tacked-on change made in the stress of adrenaline and the impending deadline.

Now I have neuroscience to back me up. Of course, there are times that last-minute changes do have to be made. Stuff happens, and has to be accommodated. But when in doubt, go with the plan. The one you know. The stress is warping your judgment and making that last-minute tweak look better than it actually is.

Steel your nerves, stay the course, and do your job. You’ll thank me later.