Students hear more by not attending class

Than attending a class with slides

students sleeping at desks
Researchers at Purdue University concluded it’s possible to “hear” more of what a professor says by not attending class, than attending a class in which slides are shown.

This study was conducted among students enrolled in a course entitled “Human Factors in Engineering,” which was delivered to students from four majors: engineering, humanities, management and technology. The course was attended by undergraduate and graduate students and was taught three times a week for sixteen weeks.

There were two separate streams of classes for the course, which was based on the textbook Human Factors in Simple and Complex Systems. For two identical lectures, two different delivery styles were used with exactly the same information presented. One lecture showed slides. One did not. The lecture that didn’t show slides employed a chalkboard where necessary to highlight visual concepts—commonly known as “chalk and talk” in academic circles.

Researchers used a twenty-question, multiple-choice quiz to test students’ ability to recall information from the lecture in four categories: oral information, graphic information, alphanumeric information, and information presented orally with visual support.

The researchers’ first hypothesis was that using slides would have a negative effect on what was said. They believed that students who saw the slides would have lower scores on oral comprehension. This was confirmed.

Students who didn’t see slides scored twenty-nine per cent higher in recalling oral information, and achieved higher overall scores with the recall of all information. “The presence of PowerPoint negatively affected the recall of auditory information,” the researchers said, adding that “graphic scores reveal there was no notable gain when using PowerPoint to display graphic information.”

Students scored just as high on graphic recall when professors used the chalkboard when needed, rather than showing slides. Slides added zero value, and had a decidedly negative effect on the ability to listen to what was said.

In addition to testing students who attended the lectures with and without slides, the researchers discovered they were testing a third group: those who didn’t attend either class but showed up to write the quiz.

Interestingly, those who read the textbook, did their work outside the classroom and showed up to write the quiz scored higher on oral comprehension than those who attended the PowerPoint lecture. They “heard” more by not attending class, than attending the class in which slides were shown.

Meme that says Eric Bergman's book, One Bucket at a Time,


Slides lead to lower retention

And, yes, they are boring

One person sleeping on a chair in a space filled with chairs facing a presentaiton.
Researchers from Universitat Autònoma de Barcelona in Spain concluded that slides impede communication, leading to lower retention by the audience.

Interestingly, this study also addressed the misplaced belief that, when using slides, the slides themselves are not the problem. If people knew how to use slideware properly, this argument goes, there wouldn’t be a problem. “PowerPoint doesn’t bore people,” these folks often say. “Using PowerPoint poorly is what bores people.”

I call it the gun argument of presentation delivery. You know. Guns don’t kill people (and all that foolishness). The simple fact is that jurisdictions with fewer guns have fewer gun deaths. Period.

Same with slides. Fewer slides equals improved engagement and less boredom—and greater retention by the audience. Best retention occurs when no slides are used.

The Barcelona study also demonstrated that eliminating slides improves both average and good presenters. In this particular study, two professors delivered identical presentations, each showing slides in one presentation and not showing slides in another. While one professor’s students scored higher overall than the other—i.e. one lecturer was a better presenter than the other—the students who saw slides from either professor scored significantly lower on a post-lecture quiz than those who didn’t.

The Barcelona study was conducted with a base of two-hundred-and-five students registered in a course entitled “The Psychology of Education.” This was a compulsory course for those working toward a bachelor’s degree in psychology.

Students were divided into four streams led by two professors. On different days, each professor taught one stream of students in the morning and one in the afternoon. For this study, each professor used slides for one class and a blackboard for the other.

The professors worked together to develop a nineteen-slide, forty-minute presentation for the class in which slides would be shown—fairly “standard” slides that all of us have seen more times than we can count. They also prepared a ten-question multiple-choice quiz to evaluate the knowledge students acquired from the lecture. The test was administered immediately after each of the four lectures and based solely on information taught during class.

Students who didn’t see slides scored twenty-two per cent higher on the quiz than those who did. In other words, by simply shutting off the projector (or simply not sharing slides in any form of remote presentation, such as a webinar), communication effectiveness can be enhanced by twenty-two per cent (and that’s without implementing a single additional idea from One Bucket at a Time).


Your audience is better off turning their backs

people turning back
The research is absolutely, unequivocally, 100 per cent clear. As humans, we cannot read and listen at the same time. Because of this simple fact, your audience will retain more of what you say if they turn their back on your slides, whether in the room or via Zoom.

Many of us already know that humans cannot read and listen at the same time. In other words, your spouse, partner or significant other is absolutely correct. You cannot be listening to what she or he is saying while also trying to read a text, even if your partner and the text are based on exactly the same subject.

The research is unequivocal. If you try attempt read the text while listening to your partner, you retain less than if you do either activity separately. You have to block out one or the other to get anything from either.

You cannot process written and spoken information simultaneously. Neither can your partner. Nor can any audience to which you present.

munich concise slide
Even a slide as simple as the one to the left overloads working memory. This slide was drawn from a research study conducted at Ludwig-Maximilians University in Munich. I changed the words to gibberish, but it has the same number of lines, words and letters as a slide that Dr. Christoph Wecker’s research team used in their study of presentation effectiveness.

During this study, the audience retained more information when no slides were shown than when even these sparse slides were shown. The slide to the left was what the research team called a “concise” slide.

The study also used “regular” slides, similar to the slide below, which contained an average of thirty-five words each. Again, I changed the slides to gibberish, but regular slides significantly decreased what the audience heard and retained from the presentation. This led Dr. Wecker’s team to coin the phrase “the speech suppression effect of PowerPoint.”

So what does this mean to you?

munich regular slide
If you apply the six-by-six guideline (six words per line and six lines per slide), you are showing thirty-six words at a time, one more than the slides that led to “the speech suppression effect of PowerPoint.” You are making it more difficult for the audience to listen to what you’re saying.

More words and more information to process (i.e. graphs, charts and tables) makes it even worse. The audience hears even less of what you say. Ultimately, this makes your ideas even less memorable for the audience. In the interim, it’s confusing them.

They will get more from your presentation if they turn their back to the slides and listen, rather than trying to follow along as you deliver your slides.

This phenomenon is nothing new. We’ve known about the folly of asking an audience to read and listen for some time.

In 2007, research conducted by a team at the University of New South Wales motivated the lead researcher to say: “The use of the PowerPoint presentation has been a disaster. It should be ditched.”

If you need a visual because you simply cannot explain yourself without one, introduce it. When it’s no longer needed, remove it from view.

And carry on the conversation with the audience. Less presentation and more conversation is the key to improving your success.

Turn standard presentations …
Into meaningful, memorable conversations with your audience

One Bucket Cover vF
One Bucket at a Time is designed to help you turn standard presentations into meaningful, memorable conversations with audiences.

For less than the cost of a single slide, you’ll gain insight into how audiences listen. You’ll learn how you can get more of what you say into the long-term memory of those in attendance, whether in the room or via Zoom.

You’ll learn to create presentations that tell a story with a clear beginning, middle and end. You’ll understand how to tell that story in a memorable way, delivering your ideas to the audience one bucket at a time. And you’ll gain insight into why answering questions is the magical topping to having your ideas understood and retained, long after your audience has left the room or signed off Zoom.

John Sweller, PhD, one of the world’s leading cognitive scientists, writes:

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

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Forbes: Stop using PowerPoint

This article in Forbes magazine suggests that presenters should stop using powerpoint because it may damage a brand.

Citing a study at Harvard, the author points out that in a business scenario, PowerPoint was rated as no better than verbal presentations with no visual aids.

The author says that research found “a more engaging and enjoyable experience for an audience with an oral presentation’s total lack of visual aids.”

Read the article.