When I discuss interfaces on this blog, I’m most often referring to software interfaces: intermediating mechanisms from our human intentions to computers and the knowledge within them. But the concept of a human interface extends far before it and beyond it. I’ve been trying to build myself a coherent mental framework for how to think about human interfaces to knowledge and tools in general, even beyond computers.
This is the first of a pair of pieces on this topic. The other is What makes a good human interface?.
Maps are my favorite kind of interface, so I want to begin with a brief story about a map I use every day.
New York, where I live, is a fast-moving river. Friends and neighbors move in just as quickly as they move out. In my three years living in the city, most of my friends and acquaintances have moved apartments every year. Too many to count have also moved in, and then away again, to some other city.
In these circles, one of my sources of childlike pride is the Manhattan subway map and schedule that’s now as clear in my memory as in the posters on station walls. I know where which trains run, at what times of the day, and which stops different trains skip during rush hour. Sometimes, when luck cooperates, I can beat transit apps’ time estimates with a clever series of transfers and brisk walks.
Obviously, I didn’t start this way.
When I first moved here, I was glued to Google Maps, following its directions and timestamps religiously. I relied on turn-by-turn directions to get around, but I also checked the iconic New York subway maps to see how many stations were left or if I was passing any landmarks or neighborhoods I liked. Over time, I learned to navigate my routes from the hazy map taking shape in my head, and now I can find the shortest path between any location in Manhattan below 100th St from memory, any time of day. (Brooklyn and Queens, I’m still working on…)
These two kinds of navigation aids — turn-by-turn directions and the subway map — were valuable to me in different ways. Though both maps of New York, I relied on the directions to reach a specific goal, namely getting to my destinations on time. The maps on the train, though, were more multipurpose. Sometimes I was looking for landmarks, other times simply getting oriented, and all along, I was also learning local geography by engaging with the map in a deeper way than the directions on my phone.
These two different uses of a map represent two different kinds of interfaces, one more focused on a specific goal, and the other more about the process of engaging with the interface.
On second thought, most interfaces have elements of both. So perhaps it’s better to say:
A human interface serves two different kinds of uses:
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Instrumental use. An instrumental user is goal-oriented. The user simply wants to get some good-enough solution to a problem they have, and couldn’t care less how it’s done.
Here’s a good litmus test to find out whether an interface is instrumental: If the user could press a magic button and have their task at hand completed instantly to their requirements, would they want that? If so, you are likely looking at an instrumental interface.
A turn-by-turn nav, a food delivery app, and a job application form are all interfaces that are used almost exclusively in an instrumental way. Let’s call these instrumental interfaces.
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Engaged use. Engaged users want to be intimately involved in the mechanics of an interface. They’re using the interface not just to check off a to-do item, but because they get some intrinsic value out of interacting with the interface, or they can only get what they want by deeply engaging with the interface’s domain of information.
A musical instrument, a board game, and a flash card set are all engaged interfaces, because they’re used almost exclusively for the intrinsic value of spending time using them. The user wants to feel the joy of performing music, not just listen to a track on a computer. They want to enjoy playing a board game, not just be handed a victory or loss. They want to learn information they’ve written in a flash card by repeatedly engaging with it, not simply read a textbook for facts they may forget.
Many interfaces are sometimes instrumental and sometimes engaged. Consider:
- A car, which is instrumental for professional drivers and commuters on a schedule but engaged for pro or hobbyist racers who are happy to drive around a loop, for the love of driving itself.
- A video editing tool, which is instrumental for video editors on a deadline who simply want a video edited to a standard style and format, but engaged for artists exploring new styles and editing techniques to deepen their craft.
- A map, which is instrumental for anyone with a specific destination in mind, but engaged for someone looking around their surroundings for any points of interest, or to understand the vibe of a neighborhood.
- Social media services, which are instrumental for businesses and influencers who seek audiences they find on these apps, but engaged for nearly everyone else.
Instrumental users have very different requirements, expectations, and goals from engaged users of an interface, and understanding the blend that applies to your particular context is a prerequisite to designing a good interface.
As I noted earlier, the ideal instrumental interface for any task or problem is a magic button that can (1) read the user’s mind perfectly to understand the desired task, and (2) perform it instantly and completely to the desired specifications.
In absence of such a perfect button, you, the designer, must conceive of the closest possible approximation you can manage within the limits of technology. In a sense, building an instrumental tool is very straightforward: you can work with your users to find out as much as you can about their intent when using the tool, and then engineer a solution that accomplishes that goal in the cheapest, fastest, most reliable way possible. The interesting details are in the necessary tradeoffs between how well you understand the user’s intent and how cheaply, quickly, and reliably you can deliver the result.
An engaged interface has no such top-line metric to optimize. Each kind of engaged interface has a different way it can be improved. A video game, for example, can sometimes be better by being more realistic and easier to learn. But this isn’t always true. Sometimes, the fun of a game comes from the challenge of learning its mechanics, or strange, surrealist laws of physics in the game world. A digital illustration tool is usually better off giving users more precise controls, but there are creative tools that lead artists to discover surprising results by adding uncertainty or elements of surprise.
In absence of a straightforward goal, to build a good engaged interface requires exploration and play. To discover the ideas that make good maps, data visualizations, video games, musical instruments, and social experiences, we need to try new ideas and see people experience them firsthand. This is a stranger environment in which to do design work, but I find the surprising nature of this process motivating and rewarding.
As a designer and engineer, I used to have a kind of moral aversion to instrumental tools and interfaces. I was drawn to creative, deeply engaging tools that I felt were most meaningful to my personal life, and viewed open-endedness as a kind of virtue unto itself.
I don’t think this way anymore.
These days, I think both instrumental and engaged interfaces are worth working on, and bring value and meaning to their users.
I do believe that the culture of modern life makes the benefits of instrumental interfaces much more legible than engaged ones: marketing tactics tout how fast and affordable things are. They talk about discounts and deals and out-compete the market based on easily quantifiable factors. Especially in business products, product makers view their customers as cold, calculating agents of reason that only pay for hard numbers. But the reality is more nuanced, and even the coldest corporate organizations are made of people. Look at the dominance of supposedly business tools like Notion or Slack. Those tools won not purely because it made employees more efficient workers, though these companies will lead with that argument. These tools won because they are beautiful and fun to use. In a tool that consumes hours of people’s days every week, beauty, taste, and fun matter, too.
Following any transformative leap in technology, it takes some time for popular design practice to catch up. This is especially the case for design practice of engaged interfaces, because unlike instrumental interfaces, where the goal is always straightforward and the leverage is in the enabling technology, better engaged interfaces often come from surprising new ideas that can only be discovered through a more open ended design exploration process.
There is always a delay between technological leaps and design explorations bearing fruit. I believe we’re going through just such a period right now. Most current work in “AI UI” is concerned about fulfilling the promise of faster, better, cheaper workflows with language models, used “out of the box” in conversational settings. This is because the implementation possibility is more obvious, and the goals are clear from the start. But there is still a second shoe to drop: interfaces that lean on foundation models somehow to enable humans to search, explore, understand, and engage with media deeper using completely new interaction mechanics we haven’t discovered yet. What direct manipulation is to the graphical user interface, we have yet to uncover for this new way to work with information.
← A beginner’s guide to exploration
What makes a good human interface? →
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