One of the guiding mottos of my work in data visualization is “eloquence through simplicity”—eloquence of communication through simplicity of design. I share this goal with many designers, present and past. Leonardo da Vinci once wrote: “Simplicity is the ultimate sophistication.” Unfortunately, people sometimes misunderstand what we mean by simplicity, assuming that simplification is a pitched battle against complexity, striving to eliminate it. In fact, thoughtful simplification preserves useful complexity and makes it easier to manage by reducing it to its essence.

I was prompted to write on this topic while reading Donald Norman’s latest book, Living with Complexity. Norman is a brilliant designer, whose work has helped to shape me, but in the midst of many gems of insight in this book, some of his ideas about simplicity and complexity struck me as logically flawed, especially the following:

Simplicity is not the opposite of complexity: complexity is a fact of the world, whereas simplicity is in the mind. (p. 53)

Did I read correctly? Complexity is a fact of the world but simplicity is not? There are things in the world that are actually complex but none that are actually simple? Simplicity is in the mind (i.e., a matter of perception) but complexity is not? We might perceive something that is complex as simple, but never the opposite? Does this make sense? To me, it doesn’t. Nothing about simplicity and complexity requires Norman’s distinction.

Although simplicity and complexity are not in conflict with one another, they are indeed opposites in that they are two poles of a continuum—the more complex something seems the less simple it seems, and vice versa. They describe our perceptions of and interactions with things that we encounter in the world. All that we encounter falls somewhere along this continuum as experienced from a particular perspective and engaged for a particular purpose. Our understanding of something, whether simple or complex, is in our minds, a matter of perception; our interaction with something, whether simple or complex, is determined by our abilities.

The closest that we can come to declaring some things as simple or complex in and of themselves is rooted in the fact that things are composed of parts or units—the fewer the simpler. In this sense, the more units that combine to form what we perceive as a thing in the world (a product, process, system, etc.), the more complex it is. The idea that simplicity or complexity resides in the thing itself, something that can be objectively measured, and not in our perception of it, falls apart, however, because there exists no single correct way to draw the lines that break something into its parts. This is a matter of perception. Things that seem simplest are those that we perceive as a single conceptual unit. The more conceptual units that must be combined to form a whole, the more complex we perceive the thing to be. In other words, the only useful way to frame simplicity and complexity is as a continuum of perception, not as facts of the world.

Through experience and learning, things that we once perceived as complex become perceived as progressively simpler. We tame complexity by breaking something down into the simpler conceptual units of which it is composed, while working to understand how they relate to one another. Through experience (practice, practice, practice), we combine these simpler units into progressively larger chunks, which we learn to hold in our minds and memory as single conceptual units. These mental constructs are called “conceptual models” or “mental models.” As a cognitive psychologist, Norman has done a great deal to help the world of design understand the role of conceptual models.

When I preach the glories of simplicity, I’m not saying that complexity is bad or that it should be ignored or eliminated. Much of what we face in the world seems complex. Much that is valuable seems complex. Complexity can be a source of incredible enjoyment; grappling with it can be a delightful form of play. We seek to understand complexity, co-exist with it, and make use of it by taming it. We do so by representing it as simply as possible without sacrificing what’s essential and useful. We do so in part by removing all that is extraneous to the thing by paring it down to its essence in relation to a particular goal.

When working with information to understand and communicate it—the focus of my work—I strive to represent it simply by removing what’s not essential, but to never oversimplify. In so doing, I hope to make complexity manageable, refusing to let it become unnecessarily complicated.

By paring information down to its essence, relative to our goals, we can make a great deal of information manageable. This is especially true of dashboard displays: single screens of information that people monitor to maintain the situation awareness that enables them to do their jobs effectively. Most of the dashboards that exist in the world fail because, by including so much that is extraneous to the information that’s needed, relatively little information can be meaningfully displayed. Screen real estate is wasted by filling it with visual content that isn’t information, and the viewer’s attention is distracted by this fluff from the little information that’s actually there. When properly designed, however, perceived complexity can be tamed, making it possible for a dashboard to display a dense and rich collection of information. Airline pilots learn to manage a huge amount of information in cockpit displays, with practice, if the displays are well designed. This potential exists in dashboards and is made possible, not primarily by the wonders of technology, but by the effectiveness of the design.

Complexity is our friend. The more complexity we learn to manage, the greater our knowledge and abilities become. Complex information is definitely our friend. It’s time we learned to tame it.

Take care,