The cognitive science behind effective ppts

I thought my slides for important presentations and lectures were good. Clean, to the point, sometimes even beautiful.

Not so.

After reading Paul and Cecik (2021) [1], I realized I often make 2 mistakes when designing and presenting slides:

Mistake 1: I read aloud bullets on a slide

Mistake 2: I often look for nice images to make the slides look good. 

These are mistakes – and I am sure I am not alone in making them. 

Why are they mistakes, you ask? I’m glad you asked. It has to do with attention and working memory. 

For mistake 1., audience members can’t listen and read at the same time – either it’s one or the other, or even worse, neither. Instead of reinforcing the message on the slide – the reading aloud can actually distract and make the message even less likely to sink in.

For mistake 2., nice images that do not directly reinforce the slide message will distract the audience from it. This strains the working memory and makes it more difficult to remember the message.

Caveat

We first need to clarify the type of presentations and teaching that benefits most from the following article. It is not the persuasive presentations in marketing and sales, for example, that require images, emotional response, storytelling, and that should have fewer than 7 words per slide. Some presentations are by their nature informative and require more words on a slide and sometimes less emotion and fluff to achieve clarity of understanding. These presentations are found in university lecture halls and highly technical trainings.  

Many business and communications gurus have long talked about bad slides, good slides and how to make them and what their role is in preparing for a presentation. Even in the academic community, “death by Powerpoint” has been a buzz word for almost 20 years [2]-[6]). 

However, Paul and Cecik analyze Powerpoint uses and abuses through the lens of cognitive science and use instructive slide examples to demonstrate their points. Paul and Cecik (2021) show us the dos and don’t of Powerpoint slide design according to four principles of cognitive science and working memory:

1. Cognitive load theory: our working memory is limited and can only attend to a certain amount of information 
2. Dual channel theory: our working memory consists of 2 mechanisms to process information – visual and verbal (language) 
3. Gestalt theory: our minds process information according to patterns, like spacing, color and shapes 
4. Constructivism: new knowledge is built on old knowledge.

This article is essentially a summary of the main points from Paul and Cecik (2021).

Cognitive load theory 

The big challenge for many educators and presenters is awareness of just how large the knowledge-gap is between the presenter expert and audience learner. And often, too much information is presented at once. This leads to an information overload that prevents understanding and thus prevents entering the working memory.

The following slide is a very complex flow chart diagram of the information processing model. For most people unfamiliar with all of the components and subsystems, it is nearly impossible to understand, even though it is a clear and logical diagram.. 

A much better representation of the model is the following model of Short term (aka working) memory. This model has less information, is simpler in direction and uses a vivid metaphor of a needle to represent working memory.

The conclusion here is to reduce the information and make the main idea clear and accessible to the audience. They don’t need to know or understand all the details.

Dual channel theory

Our working memory consists of 2 parts – the visual and verbal processing mechanisms. Understanding is made easier if both the visual and verbal work together and reinforce each other. The following slide is an example of something that I may have created previously: succinct bullets and a nice picture for aesthetics. The problem is that the “nice picture” does not reinforce the main message about short term memory. In other words, the picture detracts from the message and makes it less likely to enter the working memory.  

The next slide is text heavy. And if the presenter reads the slide text out loud, the audience may experience an interference between their reading and listening. 

A better slide design would be to offer 2 definitions with colored highlights add a visual element to reinforce the verbal one (Fig 9). And if the definitions were being read aloud, the presenter can use animations to let the first definition appear first, and then as it is being read, use animations again to highlight the key words when spoken. And then repeat for the second definition. This takes more time to design the slide, and more effort when presenting, but the audience’s working memory would benefit greatly.  

So, don’t overload verbal and visual information. Instead use both to reinforce the message.

Gestalt theory

Our minds are built to recognize patterns. This helps us to take advantage of our limited working memory. In the classic gestalt images below, our minds will perceive different patterns. 

When designing powerpoint slides, we should take advantage of our ability to create and recognize patterns to help the audience process information (our message) as easily as possible given the limitations of our working memory. The slide that follows contains a lot of phrases and dates, but it is difficult to process quickly. 

Once the slide is redesigned with spacing and font sizes to separate types of information, we can quickly get the story of the development history of the Defence procurement strategy.

We need to organize our slide information in patterns that our audience’s minds naturally look for. Once we do this, the message will probably stay longer in their working memory.

Constructivism

Finally, if we want our audience to learn something, we must understand that new knowledge only takes root in the context of old knowledge. This means we need to leverage opportunities to make learners interact and actively do something with the new knowledge. 

The next slide is a typical 7-point informative slide. It is a lot of knowledge that is expected to magically enter the learners’ heads. This will not happen by itself.

Instead, the slide contents can be reorganized spatially, with visual representations and a call to action to get the audience to do something with the information (Fig 14). This call to action makes the audience an active participant in the receiving of knowledge: they have to search their memories for examples of the types of “lean waste” and in doing so, they begin to integrate the new knowledge into their old knowledge.

The key takeaway here is that slides and presenters should give a chance to the audience to compare the new knowledge with their old knowledge to enhance the learning potential – if that is the goal of the presentation.

Conclusion

Depending on the goal of the presentation and its slides, these four principles should ideally be combined and exploited to increase the odds of the learning going from short term working memory to long term memory. This is, after all, the main goal of education. 

References

[1] Paul, J. W., & Cicek, J. S. (2021). THE COGNITIVE SCIENCE OF POWERPOINT. Proceedings of the Canadian Engineering Education Association (CEEA). 

[2] Winn, J. (2003). Avoiding death by PowerPoint. Journal of Professional Issues in Engineering Education and Practice, 129(3), 115-118.

[3] Taylor, D. (2007). Death by PowerPoint. Developmental medicine and child neurology, 49(5), 395.

[4] Tsang, O. W. (2007). Avoiding’Death by PowerPoint’and Its Impact on Teaching and Learning. LEARNING, 11(2).

[5] Clark, R. (2009). Some thoughts on writing slide presentations: Avoiding ‘death by PowerPoint’. Journal of the European Medical Writers Association, 2, 78-81.

[6] Rosler, R. (2011). How to avoid” death” by PowerPoint. Revista Argentina de Cardiología, 79(5), 1-6.