Read out all of the text on your slides

I have a simple rule for better public speaking: If you’re using slides that contain text, you must read it out, word-for-word. No paraphrasing or otherwise talking over a text-heavy slide. If there is text, read it. Exactly as written.

If your immediate reaction is “oh, that’s impossible, reading all the text would be so tedious and take way too long” then congratulations, you’re almost there. Just take that thought a little further. If you can’t read out all the text on your slides then maybe your slides contain too much of it. Strip the slides down. Simplify. But also, plan for the time needed to read out all of the remaining text.

Photo by charlesdeluvio on Unsplash

Take a look at the slide in the above image. Is it too text heavy? Probably not, as long as the speaker took the time to actually read it out. But now imagine the speaker showed you this slide but was paraphrasing—or worse, talking about something else entirely. What would happen? You’d likely either listen to the speaker and not be able to read the text or read the text and not listen. Either way, you wouldn’t be happy, and you’d feel you’re missing part of the presentation.

Keep different sensory channels in synch

We have different sensory channels through which we can receive information (including sight, hearing, touch, etc.) but our prefrontal cortex can only focus on one story at a time. If multiple sensory channels deliver congruent inputs, all is well and the inputs get integrated and processed jointly. For example, if you’re watching a fight scene in an action movie and at the same time you’re hearing the associated sounds of punches, screaming, and falling on the ground, your brain integrates these streams of information into a joint model of what’s happening in the movie. But if as you’re watching the fight scene all you can hear is a lecture about cooking omelettes, your brain won’t be able to integrate these two input streams and you’ll end up focusing on only one, either the fight or the cooking class, or you may jump back and forth between them and get confused.

Now think about what this means for giving a presentation. To keep your audience attentive and happy, you have to ensure that your audience’s visual and auditory channels are engaged and in synch at all times. The moment their channels go out of synch you lose your audience and your effectiveness as a speaker drops. Therefore, it is critical you don’t give your audience a lot of visual content¹ that can distract them and cause them to stop listening to you. Introduce the content as you speak, and keep the content and your voice in synch. And accordingly, if there is text, read it out.

Text on slides is not problematic per se

A common recommendation for making better slides is to avoid text-heavy slides altogether. In my opinion, this recommendation is too strict. While my personal style is image-heavy with few words, other styles exist and can work. Some people use text on slides almost like subtitles for their presentation, and there’s nothing wrong with that, as long as they read the exact text they have written and don’t paraphrase. The only recommendation I would make is to use animations liberally and have the text appear as you go. You want the audience reading exactly the same sentence you are reading out aloud, so only show one sentence at a time and advance once you’ve read it.

As an example of this style of presenting, check out talks by Steven Pinker². I found a recording³ that shows us his slide deck as we can hear him speak, so we can observe how he masterfully engages the visual and auditory channels at the same time. His slides are almost entirely text, he reads exactly the words that are written and then often adds a few more words or sentences to fill in gaps, and he uses fine-grained animations to never give the audience the opportunity to read ahead and lose connection.

Figures also contain text that must be read

People often forget that figures also contain text. At a minimum, there will generally be an x and a y axis label, and maybe a legend and some annotations highlighting specific parts of a figure. Take the time to read those out. It’s common for presenters to just throw up a figure—or, even worse, five figures at once—and assume the audience knows exactly what is shown and what the implications are. I have sat through far too many science talks, and I don’t know how many times I was still puzzling what quantities where plotted on the x and y axis when the speaker had already moved on to the next slide. Obviously, this is completely ineffective as a communication strategy and should be avoided.

My rules for presenting figures are to (i) only ever show one figure at a time; I can reveal multiple figures through animations but they must appear one after the other; (ii) always start out by saying “on the x axis, we see …; on the y axis, we see …;” (iii) spend some time describing the legend, if there is one; and (iv) call out any highlights or other annotations in the figure.

Yes, I realize presenting a figure in this way may take much longer than you’re used to. But it’s the time your audience needs to process the figure! Plan for it. Accept you need the time. Show fewer figures overall if necessary.

1. This includes text, but also complex diagrams or other information-dense visual displays.

2. I’m not necessarily a fan of Pinker, and I don’t endorse him or his positions. At a minimum, he seems to have poor judgement in who he chooses to associate with. None of this changes that he’s a master of presenting text-heavy slides.

3. Unfortunately the resolution of the video is rather low. If you know of a better recording that shows the same principle, please let me know in the comments.