We know that cluttered presentations and those with paragraphs of text per slide aren’t good and that the 10/20/30 rule is a guideline generally worth adhering to, but why? Could there be a scientific basis for why some presentations are better than others?
Chris Atherton, an applied cognitive psychologist at the UK’s University of Central Lancashire, studied the influence of different presentation styles on learning and retention by conducting the following experiment:
Students were randomly assigned to two groups. One group attended a presentation with traditional bullet-point slides (with the occasional diagram) and the second group attended a presentation with what Chris calls “sparse slides”, which contained the same diagrams, but minimized the amount of text, and broke up the information over several different slides. Both presentations were accompanied by the same spoken narrative.
When both groups were later tested on the presentation’s themes, it was the group shown the sparse slides that performed “much better”. Atherton suggests that well-designed presentations are superior teaching tools and improve recall and learning for a number of reasons:
- The limitations of working memory: even the students who did well in recalling themes, remembered only 6–7 themes out of a possible 30.
- The visual and auditory cortexes are not being used as effectively as they could: the cluttered slides overload the auditory cortex as it is used for written and spoken language processing.
- Extraneous cognitive load is minimised: the sparse slides may minimise extraneous cognitive load by creating fewer competing demands on attention
- Better encoding of information (into memory): having to work a little bit harder to integrate the speaker’s narrative with the pictures might actually improve our storage of the information (up to a point).