Even sermons can't save slides

I just came across a fascinating study on the use of PowerPoint. The purpose of the study was to determine if using slides would enhance recall of information presented in a non-classroom field setting—in this case religious sermons.

The study examined four test conditions to determine the congregation’s (audience’s) recall of information presented. They tested recall of:
  1. A sermon that used slides with words only.
  2. A sermon using visual images on slides.
  3. A sermon that used a combination of visual images and words on slides.
  4. A sermon that used spoken words only—no slides.
After each sermon, the congregation completed a quiz to determine how much they remembered.

When they completed their statistical analyses, the researchers concluded that their “results indicated that the form of PowerPoint presentation had some effect on recall of information communicated in the sermons.

“Interestingly, the most effective form of communication—insofar as enhancing recall was concerned—was the use of words only in the presentation, with some minor positive results for the use of words combined with visual images.

“Visual images alone were of limited value in enhancing recall, and were less effective in influencing recall than were sermons presented without the use of PowerPoint.

“Poor PowerPoint format detracted from recall, but positive PowerPoint formats were not effective in increasing recall.”

In other words, use as many slides as you wish, as long as you don’t want the audience to remember what you said.

If you want to increase what the audience remembers (and who on earth wouldn’t?), turn off the projector. Don’t share your slides. Simply carry on a conversation with your audience.


less presentation more conversation


Book encourages less presentation, more conversation

One Bucket at a Time shares secrets to informing, educating, influencing and persuading any audience

“The central theme of this book that a presentation should be a conversation is ingenious. Humans have evolved for hundreds of thousands of years to communicate by conversation. We are mentally structured to do so.

"For anyone seeking to set themselves and their ideas apart, this book is well worth the read. Eric Bergman’s techniques are a window to the future of this important human activity.”

One Bucket Cover vF

John Sweller, PhD,
Emeritus Professor of Education,
University of New South Wales,
Sydney, Australia

Whether a presentation is delivered in the room or via Zoom, a new book is encouraging those conveying their ideas to embrace more conversation and less presentation. In this, the science is clear. It’s the best way to have those ideas received, understood, retained and acted upon by the audience.

One Bucket at a Time is based on the assumption that the only reason for bringing people together is to listen to someone share something of value.

“You can have a presentation without slides,” author Eric Bergman writes. “But you cannot have a presentation without a presenter. At its core, therefore, the effectiveness of any presentation can be measured by what makes it from the speaker’s vocal cords to the long-term memory of those in attendance.

“Once you understand that thought, it becomes evident that feeding into how people listen is the most critical presentation skill to develop.”

Using an analogy of a tank, bucket and trough, the book provides guidance into understanding and developing that critical skill. The tank is the information the presenter plans to get across to the audience. The trough is the collective long-term memory of those in attendance. The goal of any presentation should be to get as much sustenance as possible from tank to trough.

The only way that happens, however, is if the audience engages working memory to transfer those ideas into long-term memory one small bucket at a time.

“The challenge is that the bucket of working memory is incredibly small, more like a child’s sand bucket than a milk pail,” Bergman writes. “And it’s easily overloaded. When that occurs, information spills out, never to be remembered.”

Using a combination of cognitive science and common sense, One Bucket at a Time makes the case that the best way to get meaningful information from tank to trough is through a relaxed, conversational delivery. The audience needs silence, and lots of it, in order to empty working memory into long-term memory before being ready to fill the bucket again.

While most presentations focus solely on attempting to teach others, Bergman’s approach is different. He advocates helping the audience teach themselves. The audience should have plenty of opportunity to ask questions to fill in understanding, which are best answered clearly and concisely.

For Bergman, tapping the potential of presentations boils down to engagement, which he defines along a spectrum. Engagement begins when working memory passes ideas to long-term memory, one bucket at a time. At the other end of the spectrum are presentations after which the audience can effectively convey the presenter’s ideas to others.

Most presentations are not engaging. In the vast majority of cases, a mountain of auditory and visual information is sent, but little is retained as soon as the presentation concludes.

“Most presentations today are like playing tennis with someone who has a large basket of balls and isn’t going to stop serving until the basket is empty, regardless of whether you show any interest in hitting one back,” Bergman explains. “In such situations, if you came to practice service returns, you might be interested in playing along for a while. But if you came to play a game of tennis, it won’t take long before you find something else to do. And this is how most audiences react.

“If the audience is reading, writing, texting, scanning their social media feed, sending an e-mail or reading a document, they cannot be listening. And, ultimately, if they’re not listening, what on earth is the point?”

One Bucket at a Time is available from Amazon, Kindle and Apple Books.

The "speech suppression effect of PowerPoint"

No substitute for simply talking to the audience

A slide from the Munich study with 35 words caused speech suppression in the lecture.
The only reason for bringing people together in any form of speech, lecture or presentation—whether in the room or via Zoom—is to listen to someone share something of value.

Without a speaker, lecturer or presenter, there simply cannot be a speech, lecture or presentation. Slides and decks are not presentations. They are written documents. If you don’t need to gather together, send an e-mail or a text. Send the slides. Write an article. Or post an item to social media.

Researchers at Ludwig-Maximilians-Universität München, led by Professor Christoph Wecker, tested two types of slides—what they called “regular” and “concise” slides—versus a control group of simply talking to the audience. They then tested the audience’s understanding and retention of what was presented.

The researchers concluded that the retention of oral information was significantly lower during lectures that used regular slides compared to lectures without slides, and that simply talking to the audience led to greater overall retention of the information presented.

Professor Wecker calls this a speech suppression effect. If you buy into the argument that presentation value comes from what the presenter says (otherwise, why have a presentation?), suppressing spoken information is counterproductive. Significantly less of what is presented makes it to the long-term memory of the audience, which negatively impacts communication effectiveness.

Unless, of course, the purpose was something other than having the audience remember what was presented.

But Professor Wecker and his team went a step further. If the audience loses a large portion of what’s said while slides are shown, is there an offsetting gain to using slides? In other words, if slides take away from communication effectiveness in one area, do they add value somewhere else?

Dr. Wecker’s team determined the answer to both questions is an unequivocal no. “It is remarkable, however, that this ‘suppressive’ effect of regular slides,” they said, “could not be demonstrated to be the downside of a trade-off in favour of the retention of information on slides.”

When presentations use what the researchers call regular slides (of precisely the same density—the same number of letters and words—as the slide above), audiences lose huge portions of what is said. And the communication effectiveness lost by showing slides is not regained anywhere else, leading to a net negative impact of using slides.

I changed the words on the slide into gibberish, but this was the exact density of a slide in the study. With about thirty-five words each, Professor Wecker’s regular slides are almost identical to the six-by-six guideline (six lines of text with six words per line) that many presenters have adopted as a rule of thumb. Dr. Wecker demonstrated that the six-by-six approach significantly decreases a presenter’s ability to move information to the long-term memory of the audience.

Words on slides simply do not work. The more the audience has to read, the less they hear. The less they retain. Period.

Even a slide with 13 words impeded the communication process. But Professor Wecker’s team didn’t stop there.
They also tested what they called concise slides. This test, using slides identical in density to the slide shown at the right (for which I’ve changed the words to gibberish once again), contained six slides (four fewer than the presentation with standard slides): a title slide, a structural slide, and four additional slides. None of the concise slides contained more than seven lines (excluding the heading) or five bullet points. The example on this page has twelve words.

The researchers also used “black” slides between the regular slides, removing all information from view. However, while the concise slides improved communication outcomes when compared to standard slides, nothing worked better than removing slides from view and simply talking to the audience. Bullet points, even those as skimpy as the twelve words shown on this second slide, overload working memory.

What does this mean for you? You have a choice. You can continue to show bullet points, quotes, sentences, charts, graphs and paragraphs to the audience while you’re talking. If you do, the message is one hundred percent clear: your communication effectiveness will be negatively impacted. The audience will be less likely to remember anything.

Alternatively, you can choose to set yourself and your ideas apart by focusing on having a conversation with the audience. Use notes to keep yourself on track and on time when you deliver your presentations. But don’t show your notes to the audience.

When you need a visual to aid understanding, use it. But when it’s no longer needed, remove it from view and carry on the conversation.

It is your best hope for having your ideas remembered after they have left the room or signed off Zoom.

most critical presentation skill