Interaction Cost

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I recently read an article that Patti Shank wrote back in 2020 about ways to reduce the challenges that learners face when learning from smaller screens. The entire article was fascinating, but for me there was a single section that stood out the most: interaction cost.

The reason this topic stood out for me was not actually related to screen size, but rather due to an argument I’d had a few years ago. It turns out that I might have easily won the argument had I used Patti’s research-based information. Let’s start with the argument and then jump into how Patti’s article is relevant

The argument

I was once told that every single slide of every single eLearning course must have some sort of clicking interaction. This was ostensibly because the learners would get bored otherwise.

At the time my main argument against this was that the specific learners and the specific content should drive the format of the slide (i.e., slide design is not based on designer/developer desires). If clicking interactions made sense for that particular content, that’s fine. However, if those types of interactions didn’t make sense, they should be excluded.

I also tried to argue that information interaction is far more important than interface interaction and that our focus should be there. For more on this topic, see one of my very first posts. Briefly, interface interaction is the clicking, dragging, swiping, etc. used to get more content from a single slide. On the other hand, information interaction is the way that learners intellectually engage with the information and process it. For example, reflecting, connecting with prior knowledge, practicing concept attainment/inductive learning, engaging with scenarios, etc.

The research-based solution

What I didn’t know at that time, was the concept of interaction cost. Interaction cost is the effort (both mental and physical) required for make the course progress. We’ve all experienced the frustration of dealing with screens that seem to scroll forever, multiple clicks to get to a single section, and needless dials and sliders, but we may not have thought about the increased mental effort required to deal these as well.

Decreasing cognitive load is the key driving force for many of Mayer’s principles of multimedia learning. By requiring learners to click, scroll, drag, etc., we are increasing the cognitive load required to complete the course. This is likely not our goal. And all these additional interactions can backfire when cognitive overload occurs, and learners’ brains become overwhelmed. While interface interaction can be exciting and flashy, it isn’t necessarily the best way to present content.


I always have and always will keep cognitive load on the top of my mind when designing slides, to help determine whether interface interaction is adding or subtracting from the slide. If it impedes learning, I will always seek to eliminate those flashy clicks, drags, and swipes.


Shank, P. (2020, Jan). Minimizing Challenges Of Learning From Smaller Screens. Retrieved from