December 6, 2021

I, Science

The science magazine of Imperial College

Anne Petzold explores the psychology behind making Power Point presentaions less painful and more memorable

power pointWhat does psychology tell us about effective slide show design?

Assuming, conservatively, that you held a Power Point Presentation (PPP) once a term during your A-levels and your studies, you will have produced 15 presentations by the end of your Undergrad. How many presentations will you have heard? Uncountable. Which ones did you find memorable or at least pleasing to the eye? Probably a small number only.

Presentation softwares are constitutive components of most OS environments. Considering their market share for desktop computers and laptops in 2014, Microsoft Windows (90 %) with its PowerPoint software supplies the most heavily used presentation software, followed by Mac (7 %) with Keynote, and Linux (1.3 %) with a diverse range of presentation solutions. The first PPP was delivered to Microsoft employees in 1992, marking the beginning of routine use of PPPs in businesses and classrooms. The jury is still out for the actual benefit of PPP, especially in the classroom. However, if one of the oldest hands of cognitive psychology judges it worth to conduct dedicated research and to produce whole books about these presentations, something may be foul in the state of PPPs.

After conducting psychological research for half a century, Stephen M. Kosslyn knows a thing or two about the mind. His most notable research is focussed on mental imagery: the ability of the mind to generate a representation of the physical world. His current work at Stanford University and the Minerva Project in San Francisco focuses on the science of learning to discern optimal ways of learning with and beyond the traditional classroom.

Almost a decade ago, his research into the use and abuse of PPPs went into a book, “Clear and to the point: 8 psychological principles for compelling Power Point presentations”. Follow-up research articles aimed to analyse the anecdotal “flaws and failures” of PPPs empirically and to flag do’s/don’ts.

So, what does psychology tell us about effective slide show design?

To get your point across and make it memorable, cater for the ways we process information. Firstly, information needs to be actively perceived in a way that allows us to store it in memory – a process referred to as encoding. If an audience cannot encode the information, it may as well not exist. Secondly, information needs to be kept in memory over multiple slides (working memory). Lastly, the audience must fit the presented information into a reference framework of previous knowledge, drawing on experience (long-term memory). Kosslyn argues that presentation efficiency can be improved by playing to the strengths of human information processing, i.e., by observing “cognitive communication principles”.

For instance, discriminability, organisation and proper emphasis facilitate encoding. Kosslyn conducted an initial survey of a random set of PPPs available online and revealed that even these seemingly obvious rules are often violated.

To keep your presentation pleasant and the flow going, avoid particularly annoying and frustrating flaws. Working memory is one of the major bottlenecks of information processing: its capacity is limited and can be easily overloaded by irrelevant information.

Keep in mind that “information” does not only include intended content, but also all the details of the presentation itself, such as the visual setup of the slide show, the voice and intonation of the presenter, etc. The audience will expect a visual change, such as a change in font colour or a change in tone, to signify relevant information, and attention will have been diverted unnecessarily if it does not.

Also, accessing long-term memory to associate meaning with the presented information diverts capacity and attention from the presentation. Kosslyn conducted a survey among a range of participants about particularly annoying – distracting – faults of recently attended PPPs. People judges PPPs that “[…] contained too much material to absorb before the next slide was presented” as highly annoying. Slides where “[t]he main point was obscured by lots of irrelevant detail” were scored as similarly frustrating.

Finally, keep in mind that many flaws and failures are hidden and not apparent to the audience or yourself. We are often not aware of the particular communication rules that PPPs may or may not obey. When asked to rate slides for the presence of a violation of communication rules and to indicate why a slide violated particular rules, participants often failed to detect these violations and/or could not explain why they constituted a violation.

One might question the relevance of studies that take PPPs from the classroom into the lab and dissect their visual dimensions alone. However, studying the quality of the presenter itself, well, that’s a really hard nut.

The study was originally reported in Kosslyn et al. 2012, Frontiers in Psychology

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