Picture this…

Does visualization help to more effectively communicate concepts in computer science education to learners? The answer seems, to me at least, to very clearly be yes. It seems as though the jury was out in 2003 when Naps et al. published Exploring the Role of Visualization and Engagement in Computer Science Education.

In this paper, Naps et al. summarize the results of the Working Group on Improving the Educational Impact of Algorithm Visualization. Based on a survey they conducted, the group points out two key reasons that the use of visualization in computer science education may have not yet gained widespread acceptance. These were:

  • “From the learner’s perspective, …visualization technology may not be educationally useful.”
  • “From the instructor’s perspective, …visualization technology may simply incur too much overhead to make it worthwhile.”

They go on to conclude that “learners who are actively engaged with…visualization technology have consistently outperformed learners who passively view visualizations.” And, in fact, that:

Visualization technology, no matter how well it is designed, is of little educational value unless it engages learners in an active learning activity.

I’m fairly confident in stating that this holds true for any teaching materials, not simply visualization technology. Nevertheless, the authors maintain that visualization is more or less worthless unless it actively engages the learner. To be clear, they refer not only to carefully constructed, animated, interactive visualization tools. They also include diagrams–even those found in textbooks–under the heading of “visualization technology”. To this end, the authors provide an exhaustive accounting (or rather, an extraordinarily verbose data dump) of the results of their survey. Based on these results, they both provide a set of best practices for visualization design, as well as a framework for further research around the effectiveness of visualization technology. This framework aims to explore the effectiveness of visualization along the lines drawn by Bloom’s taxonomy.

On the one hand, I’m all for some real science in computer science. Far be it from me to groan when an HCI researcher takes the bold step of demonstrating and calling for additional academic rigor in research. For this, thank you, Naps. On the other hand, I’m stumped by their statements that motivate this call. In their introduction, the authors state that “intuition suggests that…graphical representations would help one” in understanding computer science concepts. Yes, intuition does indeed suggest this. Not only that, the piles of scholarship cited here and elsewhere bear this out–graphical representations do aid in learning. In other words, our intuition doesn’t just suggest this–this is reality. Very little the citations in this paper draw on general education literature. Rather, most of the cited literature deals directly with the use of visualizations in teaching algorithms and data structures. This seems like a non-negligible oversight to me.

In the end, I’m happy to see these sorts of endeavors in our community, dated as they may be. However, their foundational argument doesn’t have me sold. Certainly, the quality of visualization technologies runs a wide gamut. Please don’t exclude diagrams from your articles and books just because Naps told you they’re worthless if they don’t actively engage me–I, for one, appreciate them and find them extremely useful…

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