If you read our blogs, you’ll notice that we talk a lot about making whatever you publish about science easy to understand. This may feel repetitive sometimes. And being scientists ourselves we get why you may think it’s the least important part of any presentation. But science communication is here to stay, so it pays to learn to do it right. To quench that thirst for a more in-depth explanation, here’s an entire blog devoted to why we think it is key to any talk, article or website to be easy to understand. Introducing mental bandwidth Every person, no matter their education, background, gender or income, has a certain capacity for retaining, processing and remembering information. This is described by the Cognitive Load Theory, which states that people have a limited short term memory and working memory. To make it easier to talk about, we pooled these limited capacities into ‘mental bandwidth’. It’s a nice metaphor because cognitive load does resemble your internet connection: when you’re just emailing and browsing everything is fine, but download and install a large game or software update, and you reach the limits of your connection and every activity just goes a little bit slower. Listening and reading at the same time doesn't work Your bandwidth is most obvious when you’re dealing with two competing streams of information, say listening and reading at the same time. This is why bad slides full of text or unclear information are so detrimental to the success of a presentation. You are confronted with a slide with the fluffiest graphs, vague text (and lots of it!) and no conclusions, you will stop listening and devote all your mental bandwidth to the ‘puzzle’ on screen. [...]