Better PowerPoint: What We REALLY Remember
Ubiquitous use of PowerPoint for information processing, particularly as a standalone offering (a quick search through Slideshare.net confirms the growing trend of on-demand PowerPoint presentations).
PowerPoint-based presentations that look very similar, making it more difficult for messages to stand out (how many presentations have you seen lately where either you can’t remember who created them or they looked similar to something else you saw months ago?).
These observations invite the question: how does one distinguish a particular on-demand PowerPoint presentation, given existing informational noise and competition?
1,540 subjects participated in the study, where I started with a very basic question applied to a very basic on-demand presentation: How many slides does a viewer remember, on average, from a text-only, standalone online PowerPoint presentation containing 20 slides? To answer this question, I used the isolation effect theory, according to which, items (in this case slides) that stand out in some way from a homogenous list have a higher likelihood of being recalled.
- Participants remembered an average of 4 slides from a 20-slide, standalone, text-only PowerPoint presentation.
- Neutral visuals help, but they don’t change the rule of 4. There was a statistically significant difference between the recall of content in text-only slides versus slides that contained text and neutral visuals. However, the recall rate did not exceed 4 slides in any of the 26 PowerPoint deck manipulations included in the study.
- Participants tended to remember the same content, not slides at random, as was predicted. This means that it may be possible to control what people remember by using a certain set of criteria.
- For standing out, 5 is an important number. Applying the isolation effectevery nth slide (3rd, 4th, or 5th) did not impact the overall recall of an entire deck.However, when a change was made every 5th position (i.e., slides 5, 10, 15, and 20), those slides tended to be remembered better than any other randomly selected slides from that deck. The reverse was true for slides changed in every 3rd and 4th position.
These findings can be linked to a set of practical and immediately transferable guidelines for anyone who creates on-demand presentations. Let’s start with the first one.
Part One: The Magic Number Four
No article on memory capacity and short-term memory can escape without quotingMiller’s classic “seven plus or minus two”, which has often been used in the fields of psychology and education as pillars for creating guidelines on information processing and communication design. Back in the 50s, Miller contended that there is a limit in the number of items that working memory can retain (namely, 7±2).
Other researchers have since questioned the limitations of memory capacity,suggesting that the new magic number is 4±1, and that people form clusters of no more than three or four items to recall. When memorizing lists, some researchers observed that items in a list entered a fixed-capacity rehearsal buffer and displaced a randomly selected item already there, when the capacity of approximately four items had been exceeded. Newer research suggests that the capacity for visual working memory is limited to four items.
In a “list” or PowerPoint presentation of 20 slides, if information after 4 slides starts to be displaced by other items that were just viewed, it makes sense that the average recall rate would be 4 slides from the entire list. The good news is that if we know that the amount of slides people remember is limited,that means we don’t have to try so hard on every single slide we present.
Let’s Test What You’ve Learned. Which is Better?
Even though this study was created in an on-demand setting, let’s reflect how this would apply in a face-to-face setting, where a presenter is involved. Imagine that someone had to present the file below. Can you sense how everything is so intense on every slide and each slide may have taken a long time and quite a bit of money to develop?
And at the opposite end, can you tell how “weak” the content is in the example below, where someone did not take that much time to place text in a sequence of slides?
So, which way is better?
Surprisingly, while both examples may have good content, they are equally bad where memory is concerned. This is because when everything is equally intense or equally weak, something has got to give. In an environment where there is a presenter, the content has a chance because the presenter can do something to deviate from sameness (e.g., invite participants to answer questions, participate in a group exercise, or switch from PowerPoint to a software demo).