Blog | Wednesday, May 18, 2011

PowerPoint bulleted list theorem (Why we should not use long bulleted lists)


Most of us associate PowerPoint with lectures in large darkened halls with many slides of bulleted lists accompanied by a droning voice. So what is wrong with the bulleted lists in PowerPoint? I was preparing to conduct a workshop on PowerPoint and Education and found some theoretical basis for why we should not use bulleted lists when presenting. As you see, I do use them freely in documents.

[Author's Note: This is presented as a theorem just to make it interesting. It is just my very simplistic interpretation of work done by many people and better presented elsewhere. See the references at the bottom. Readers should refer to the Atkinson, Mayer reference below for an excellent and more detailed description of these concepts. My hope here it to get readers interested both the cognitive theories related to this topic and the practical applications of these.]

Some of the biggest advantages of using tools like PowerPoint are:
1) use of multimedia elements,
2) integration with audience response systems,
3) creating branching/non linear presentations based on audience needs,
4) more legible text, clearer images,
5) ability to re-purpose/reuse material from other presentations (can be dangerous), and
6) options for distribution and sharing.

Thus, it is quite obvious, why PowerPoint (and other technology) is used so much in education. It is very important to remember the steps for using technology in learning:
1) understand how people learn,
2) think about how educators can facilitate this learning process, and
3) then think about how technology can help improve this facilitation process.

When we keep these three steps in mind while designing our presentations, it will lead to better use of PowerPoint. When the presentation "fails" it is most likely because we ignored one or both of the first 2 steps and jumped straight into the technology (PowerPoint).

Compare this bulleted list in PowerPoint:


To this:



Statement:
Using bulleted lists while narrating during presentations is detrimental to students' learning.

Axioms:
--Working memory (formerly called short-term memory)
---Processes incoming data/information
---Connects it with existing knowledge/wisdom
---Encodes it into long-term memory

--Working memory has limited capacity to process information
---It has two separate channels
----verbal/auditory input
----visual input
---Each channel has a limited processing capacity
---Text is processed by both visual and verbal channels (you know now where this is going, right?)

--Meaningful learning requires substantial amount of cognitive processing in both channels
---Select and pay attention to incoming data
---Organize the data
---Integrate it with prior knowledge


Argument:
Information presented in a manner that overloads the processing power of the Working Memory makes learning difficult.

Bulleted lists which are multiple concepts presented as text are processed by both the visual and verbal channels.

When you start talking around these lists, the words you speak are processed by the verbal channel.

The audience struggles:
--to correlate the text on the screen with the words you speak
--to grasp which bullet you are talking about
--to decide whether to just read the slide or listen to you talking

This struggle is not germane to getting a deeper understanding of the presented material. It actually takes away from the learning process.

Conclusion:
Presenting (long) bulleted lists while narrating during presentations is detrimental to learning.

Quod erat demonstrandum!

Corollary1:
While narrating in a presentation, showing an appropriate image on the screen is better than showing a bulleted list. This leverages the dual channels to facilitate learning.

Corollary 2:
Putting both an image and a lot of text on a single slide is detrimental to learning. This can overwhelm the visual channel.

References:
Working memory (Baddley and Hitch) [PubMed][Wikipedia]
Dual Coding Theory (Paivio) [PDF article][Wikipedia]
Cognitive Load Theory (Sweller) [EduTech Wiki]
Select Organize Integrate Theory (Mayer)
Cognitive Theory of Multimedia Learning (Mayer and Moreno)
List of learning theories at Learning-theories.com
Richard Mayer's full text article [PDF]
5 ways to reduce PowerPoint overload (Atkinson and Mayer)

Neil Mehta MBBS, MS, FACP, practices internal medicine at a large tertiary care hospital in Ohio. He is also the Director of Education Technology (Academic Computing) for his medical school and in charge of his hospital system's home grown Learning and Content Management System. He is interested in use of technology in education, social media and networking, practice management and evidence-based medicine tools, personal information and knowledge management. This post originally appeared at Technology in (Medical) Education.