What's in a slide presentation?

Some comments that your audience will never make in question time…


original image

I'm writing this editorial in the middle of a scientific meeting that I'm attending; and it's a cracking meeting by any scientific standards. But it has reminded me, again, of standards that speakers often unthinkingly apply to their presentation; and some of them could be improved.

Powerpoint can be a wonderful tool, if used wisely; equally, as I once heard, it can turn an inspiring scientific talk into a “glorified shopping list”. Now I have the impression that that problem of overuse of bullet point lists is being replaced by another, particularly in cell biology: it's the continuously running movie – e.g. fluorescence or phase-contrast microscopy – that loops incessantly in the background whilst the speaker is explaining what it means. This starts as a justified and scientifically important glorification, but ends up just irritating the audience. Images grab attention; moving images doubly so. Maybe I was the only one in the audience affected in this way – I doubt it – but I find it very hard to concentrate on the scientific messages with such cinematography running continuously. And suddenly, another little cinema opens in a new panel on the same slide – by the end there can be several little science cinemas running simultaneously on the same slide. It's beautiful and impressive, but please stop the looping! A few times is enough. On the other hand, I am, on the whole, impressed by the skill with which presenters depict their models via pictures drawn in Powerpoint; but here, the animation functions of the Microsoft product are mostly underused: most of the time a complicated model is presented in total. A step-wise appearance of the various components would aid understanding, I believe.

Another common practice continues to be the presentation of large quantities of primary data (gels; micrographs; sequence comparisons; panels with combinations of images, symbols, and numerical values – you name it). Yes, science does need to be presented with reference to results obtained in the lab. However, I feel that the larger the amount of primary data on a slide, the less the audience engages with and tries to understand it. I've observed that at the end of the vast majority of talks there are no questions about how the results in slide so-and-so were obtained, or what the Ca2+ concentration was in a particular experiment. That also means that there is less audience engagement with the experimental work: possibly a missed potential for useful input? I believe that primary data should be presented in a quantity necessary to communicate crucial examples, and no more. Striving for completeness of data is likely to make the audience less curious about what exactly was done. Isn't such curiosity part and parcel of a scientific meeting?

Finally, what's the “message” in the header text of the slides? Is there a message? Many speakers do entitle their slides with statements of the biological process or the finding that they are presenting, e.g. “Lis1 is required for dynein to function in yeast and man”. But many still have titles such as “The role of…” or “The mechanism of…”, despite the fact that they have, in truth, something much more specific to say. With the chronic lack of time to present a full picture during a talk, stating a finding or biological phenomenon in a slide title – i.e. containing subject, object and verb – is invaluable: it immediately gives viewers a piece of information, regardless of whether they then have the time to digest the rest of the slide.

Most presenters do make wise use of bullet points these days, restricting them to summary slides – particularly the main take-home messages at the end of the presentation. But for greatest clarity, their entry should be animated. I can't animate my conclusions here, but here are some closing bullet points:

  • Don't let movies loop continuously in the background! Please!

  • Limit the quantity of primary data that you present.

  • Build complicated models in stages, using animation functions.

  • Give slides statement-like titles that communicate their main message(s).

original image

Andrew Moore