Better PowerPoint Slides - Coherence

I recently gave did a short training session on how to more effectively use slides to encourage learning.  Powerpoint (or like software) is prevalent in college courses, but slightly less so at the K-12 level.  The most recent numbers I could find for K-12 were from 2009 survey of teachers.  This study reported that 63% of teachers said they “sometimes” or “always” used software to make presentations.  It’s hard to say whether this report accurately reflects current use levels, but when I asked teachers during my recent training session they said it seemed reasonable given what they had seen among colleagues.

It is even less clear from published research whether using PowerPoint leads to increased learning.  In fact, at the very best research has pointed to mixed success with PowerPoint.  In some cases there appears to be a learning advantage from using PowerPoint while in other studies results suggest that it might actually hinder learning. 

One way to approach this problem is to simply ban PowerPoint from classrooms.  This argument has been made for classrooms specifically, but also for meetings (see this article).  However, what this approach ignores is that there is research showing that learning increases if visuals are used effectively.  

The multimedia principle tells us that people learn more and are better able to apply what they have learned when they are instructed with both words and pictures than when they are instructed with words or pictures alone (Mayer 2009).  This makes sense when we consider the dual coding assumption.  According to Paivio (1971), there are two ways people learn new material: verbal associations and visual imagery. The theory, called dual-coding, proposes that both visual and verbal information is used to represent information in memory. However, visual and verbal information are processed through distinct channels in the human mind, creating separate representations.  Either or both visual and verbal codes can be used when recalling information.  When asked to recall the stimulus, such of an animal, the person can retrieve either the word representing the animal (e.g. “cat”) or the image of the animal individually, or both simultaneously.  Dual coding postulates that storing stimulus two different ways increases probability that the stimulus will be remembered.  If this is true, why isn’t a visual tool like PowerPoint more effective?

The reason the research on PowerPoint is more mixed is probably due to the way it is applied in the learning environment.  In many cases PowerPoint is used to display large amounts of text with no picture or a small (and not always relevant) picture.  Pollock et. al. (2002) argue one of the biggest issues with PowerPoint might be the combination of narration (voice) and text at the same time, which has been referred to as “cognitive load”. 

So, how do we maximize the learning potential that PowerPoint offers us (by using “words and pictures” to increase learning)?  Richard Mayer (2009) came up with twelve principles that can be applied to using multi-media in the classroom to improve learning.  In this post I will cover the first five: coherence, signaling, redundancy, spatial contiguity, and temporal contiguity. 

Our first goal in developing a high quality multimedia experience for students is to reduce extraneous processing demands (avoid cognitive overload).  By applying the five multimedia principles from Mayer we can achieve this goal.  The principles:

Coherence Principle – People learn better when extraneous material is excluded rather than included.  For example, students learning about virus performed better when the lesson did not include interesting, but irrelevant facts about viruses. 

Signaling Principle – People learn better when cues that highlight the organization of the essential material are added.  Cues such as arrows, highlighting, and flashing improved learning.

Redundancy Principle – People learn better from graphics and narration than from graphics, narration, and printed text.  When text and voice are both present it overwhelms the channel the “words” channel and reduces learning.  If text is short it may increase learning. 

Spatial Contiguity Principle – People learn better when corresponding words and pictures are placed near each other rather than far from each other on the page or screen. 

Temporal Contiguity Principle – People learn better when corresponding words and pictures are presented at the same time rather than in succession.  For example, don’t describe the steps in a process then show the process.  Describe and show the process simultaneously. 

One principle we should apply to our development of multimedia (including slides) is coherence.  Below is a slide from a presentation given to the San Francisco Unified School District (SFUSD) Board of Education on September 29, 2015.  The presentation was designed to present the results for the 2015 Smarter-Balanced Assessment Consortium results.  The slide is difficult to read because of the clutter.  There are two types of charts: stacked bar and line.  The stacked bar chart differentiates between two level scores (“met” standard “exceeded” standard) while the line chart displays “met” and “exceeded” combined as a single number.  The bars are labeled with the combined proportion of “met” and “exceed”, but the line chart does not have data labels.  The bars are stacked, but there is no way to tell the value of the “met” versus the “exceeded”.  The y-axis has values, but it very difficult to discern the value of the portions of the stacked bar chart or the line chart.  There is a table below the chart that shows the values of combined “met” and “exceeded” for both the bar chart and the line chart.  This chart is confusing because it lacks coherence.  There is too much information included, which distracts from the important comparison. 

The second example below is the slide redesigned with the aim of improving coherence.  First, I removed unnecessary information: the stacked bars, the table of data, and the y-axis labels.  Second, I used one type of graph to compare SFUSD to the national pilot study data.  Third, I removed extraneous lines that were not necessary.  The redesigned slide is aimed at making it easier for the audience to quickly see what is being compared and analyze the results. 

Whether we are using slides to enhance learning in a classroom full of students or to present to a school board, by applying the principle to coherence to all our slides (not just charts) we vastly improve communication and increase learning.  

Mayer, R. E. (2009). Multimedia learning (2nd ed). New York: Cambridge University Press.

Paivio, A (1971). Imagery and verbal processes. New York: Holt, Rinehart, and Winston

Pollock, E., Chandler, P., & Sweller, J. (2002). Assimilating complex information. Learning and instruction12(1), 61-86.