The Zen of Presentations, Part 61: Blocking and interleaving

Academics tend to treat everything like a manuscript. In a manuscript, if you have multiple experiments, you do all the methods for all the experiments in a block, then all the results in a block. That is:

• Methods: Experiment 1, 2, 3
• Results: Experiment 1, 2, 3

This is a bad idea in a verbal presentation, because you’re making your audience have to work to remember everything. The reason why you tell someone the methods at all is because they help you interpret the results. In the example above, someone has to remember all the methods for all three experiments, using their working memory, before getting to a single result.

Much better to do it by interleaving the methods and results, and blocking the experiments together.

• Experiment 1: Methods, Results
• Experiment 2: Methods, Results
• Experiment 3: Methods, Results

This way, you don’t ask people to remember as much. Plus, the results of the one experiment often tell you why needed the next experiment, which often informs you why picked the particular methods you did.

Interleaving photo by Danny Nicholson on Flickr; used under a Creative Commons license.