Principle 2 - Use Black Slides

I once knew a famous developmental biologist who would sit in the front row at talks, bow his head low, and shield his eyes from the slides with his hands. He would listen intently to the description of the problem and the experimental approach and then cautiously peek up from above his hands to glance at the data when he thought the results were being shown. He would then quickly nestle his head back into his hands. He always asked the best questions after the talks. This biologists came up in the era before Powerpoint and I believe he was deeply distracted by all the graphics that are now displayed on slides. He wanted to understand everything the speaker said, so he did what he had to do to focus his attention on the speaker's words. 

The best way to convince the audience to listen to what you are saying is to eliminate any distractions. Remove extraneous visual stimuli and everyone in the audience will look at you and listen to what you are saying. Remember, they came to hear what you are saying and they are on your side, so don't be afraid to capture their full attention with your words. I admit that it can be somewhat unnerving to look at the audience and to realize that everyone is looking directly at you. A normal response is to want to look down or to look away. Resist this temptation! Look back at the audience. You will get used to this and you will soon learn that seeing everyone looking at you is the best sign that you are truly communicating with your audience. If you have lost your audience, you will see many heads not looking at you and not looking at your slides. Your "listeners" will be looking instead at whatever electronic device they brought with them. They are bored and they are not learning anything from your talk.

In the first entry, Principle 1, I provided the simplest way to focus the audience on your words and the relevant data, by removing words from slides. In later posts I will discuss other ideas to improve these data slides. But now I want to introduce you to my favorite "trick" for keeping the audience's attention. Insert black slides whenever you can explain things more clearly with words than you can with images. For example, I almost always start my talks with a black slide. When I start talking, everyone is looking at me and I know I have their attention from the beginning. I start by describing the problem. That is, I start, immediately, by talking about the science. Often I start with a very big picture view of the problem. Sometimes I start by discussing a commonplace observation that is related to the topic. Only rarely is an image required to introduce the broad view, but then, I quickly move to images that help me to explain the problem under study.

Later during the talk, I use black slides periodically as a visual pause. In these interludes, I review what I have presented so far. I try to use plain language to make sure that everyone in the room is following the major implications of each set of experiments or observations. Then, before I click to the next slide—which might show data, or a model, or some complex image which I will explain in detail—I say something along the lines of "Now, to test this idea we did experiment X" or "This raises an interesting issue, which is illustrated clearly in the following image." Then, I click to the next slide and we get back into the experiments.

These black slides also give me an opportunity to check on the state of the audience. Of course, when I present data slides, I usually point at specific items in the slides. This means I am not looking at the audience. With a black slide up, I can turn to the audience and discover if people are still interested. Are people looking at me or are most people looking at their iPhones? If they are looking at their iPhones, then I need to do something to recapture their attention. (I hope, though, that by the time I finish this blog you will have all the skills and tricks required to keep everyone's attention through the entire talk.) One simple trick to recapture the audience is, simply, to pause. Just stop talking for a few seconds. Everyone will look up to see what happened. Then, when everyone is looking at you, bring everyone back by summarizing what you have shown so far. 

It takes a little practice, but don't overstay your "visit" to the black slides. Don't launch into a huge monologue. The black slides provide a break from the visuals, and the visuals provide a break from the black slides. Everything in moderation.

Note, I said black slides, not blank slides. I have argued with some folks who feel that a blank white slide is just as effective as a blank black slide. They may be right, but I am not so sure. My impulse when I see a white slide is to look at the slide expecting something to appear on the slide soon. In contrast, my impulse when I see a black slide is to think "Oh, there is nothing to see here" and I automatically look at the speaker and listen to what they are saying. I would love to see a controlled study of the effect of white slides versus black slides on audience attention! For now, I encourage you to use black slides.

One technical note. If you do decide to start with a black slide, which I strongly encourage, be sure to alert the audio-visual experts who are helping you with your slides that your first slide is black. Otherwise, they may automatically start clicking through your talk looking for the "real" first slide. Needless to say, this will distract the audience from what you are saying!