What It Means to Design Technology That’s “Pass-Through”

Amber Case
8 min readJul 26, 2023


Windows are the ultimate pass-through technologies.

The best example of a technology interface is one you rarely notice — even if it’s powerfully enhancing your reading experience of these words right now.

I’m referring, of course, to glass windows. We rarely notice them or even think of them as technology; when we use them, the window’s physical components are not even something we physically see (unless the glass itself is notably dirty).

When you look through a window, you focus on the view, not the window. It’s the act of using it that renders the window invisible. We can see a window at the corner of a room. We know it is there. It makes its presence known to us, but when we look through it, the window disappears.

This illustrates a key point made in a famous quote by Xerox PARC’s Mark Weiser, which many designers misinterpret:

“A good tool is an invisible tool… By invisible, we mean that the tool does not intrude on your consciousness; you focus on the task, not the tool.”

The second part of the quote tells all. It’s not about the device itself being invisible, but the act of usage rendering it invisible.

For instance, when we use a hammer, we focus on the nail, not the hammer. To a good woodworker, the act of using the hammer renders it invisible.

When a technology is pass-through, we focus on the nail, not the hammer.

We can call devices which follow this principle “pass-through” technologies. But we would not want a hammer we’re using to literally be invisible.

In a similar way, a car is very much not invisible. But when we drive it, the car becomes a pass-through technology to get us safely to our destination. Its many features center our focus and provide context to us as we drive, but we don’t have to think about the many systems in the car keeping the tires moving or the motor going. It’s possible to focus on getting to our destination.

Pass-Through vs. “Invisible” Tech

When designers fixate on invisibility as an end in itself, they make technologies that assume they know what humans want. (“Smart home” technology is notorious for this.) But when people can’t actually see the device, they lose their sense of agency. And when these devices break down, they become doubly frustrating, since the user isn’t sure how they work.

By invisible, technologist Mark Weiser means the technology is not the focus of our awareness, existing on our periphery so that the task at hand remains central to our awareness. As he put it:

“Technology shouldn’t require all of our attention, just some of it, and only when necessary.”

This insight is also core to the concept of pass-through technology.

Identifying, let alone designing pass-through technology is hard. By definition, it’s best represented by tools we use so often and so intuitively, we don’t even consider them to be technology. Pass-through devices like windows, eyeglasses, and light switches are so essential to our everyday modern life, we just focus completely on the task — seeing — without any thought about the underlying technology.

But training ourselves to recognize pass-through technology is crucial for calm design.

Un-calm tech is by definition anti-pass-through. It alerts itself when not in use. It tries to do too much for us. It breaks down in weird ways. It is not designed with humans in mind — rather than facilitating human control, it controls us.

How Google’s Pass-Through UI Won the Internet

To better grasp the concept, consider examples of pass-through technology in the digital realm:

As I mentioned in my last post, Google search beat out many other, better-funded competitors in the late 90s/early 2000s. To this day, it is a great example of pass-through technology:

Google Search features a clean white web page, with only a single task UI at its center. You just focus on your task.

Compare with one of Google’s predecessors in the 90s:

Ask Jeeves represented an early search engine wrapped up in the image of a butler’s assisting charm. Ask Jeeves later renamed themselves to Ask.com, minimizing their interface to a single search box. Image credit: PracticalEcommerce

Another common confusion is to assume pass-through means simple. But that’s not always the case. When Google first launched, many complained that keyword searches generate a wall of text results. (Search result summaries and thumbnail images have only been added relatively recently.)

Instead, Google’s designers preferenced displaying as many results as possible, to help us quickly complete our task; we just trained ourselves over time to discern valuable results among the chafe. Once learned, Googling became second nature to us.

The Pass-Through UI of Minecraft & TikTok

Minecraft’s in-game interface is another example of a pass-through technology. While seemingly complex on the surface, the interface is unintuitive until you get used to it, and feel bonded with the game.

Minecraft’s interface takes a little while to get used to, but once understood, supports exploration and life inside of a metaverse simulation based on creation, collaboration and survival. Image via Minecraft 101.

All Minecrat’s on-screen UI functions are based around the game’s initial core purpose: Use your creativity and gathering skills to Survive a night against the Creepers — in-game enemies that you must build defenses against in order to have another day of gameplay.

That way, players can remain focused on learning all the game’s functions and how they relate to each other, all for the purpose of surviving and defeating the Creepers and the world’s other attacking beasts. It’s only after this that players realize that the UI they first learned for survival purposes can also be leveraged to thrive — creating beautiful and ambitious homes for themselves, or even the collaborative artworks with other players, all of which helps make Minecraft enormously popular over a decade after launch.

Pass-through technology is so powerful, it can be leveraged for questionable end goals. For instance, TikTok, the largest app in the world, is among the most pass-through apps on the Internet. The interface is so pass-through that people can easily get lost in it.

TikTok operates in a highly intuitive manner that eliminates the typical need for a user to manually search for content of interest, as one would do with Google. Instead, it leverages a sophisticated algorithm that autonomously curates and delivers videos to users based on their unique preferences and behaviors. This personalized approach to content delivery presents an uninterrupted stream of videos tailored to taste.

Even posting simple videos is easy — especially as compared to YouTube, which confronts content creators with a full-fledged video editing suite. This also illustrates how pass-through comes with its own concerns: TikTok is so thoroughly seamless, It can easily become addictive — and in the end, serves the TikTok’s corporate interests more than human needs.

We can look at the idea of TikTok as more of a controlling technology, in that TikTok is selfish for itself (i.e. the company), and creates a selfishly pass-through technology that aligns with itself rather than the needs of the people using it. In this case, it’s important to look at the line between when these kinds of automations serve the people and when they serve the app developer.

Poor examples of pass-through technology

PayPal’s app Venmo largely confuses ease of use with pass-through, automatically connecting you to your Facebook friends and to vendors through a QR code. But if you’ve ever felt a momentary panic while preparing to Venmo someone, not quite 100% sure whether the recipient you looked up on your account is not another contact with a similar name — you’re experiencing a lack of pass-through.

Venmo was designed to be frictionless, a popular principle in app development. But frictionless is not always the same as pass-through. In Venmo’s case, we might want some friction. Imagine quickly paying the wrong person and not being able to get the funds back.

During the payment process, Venmo doesn’t display anything about your payment’s connection history with a given person — even though it can sometimes be difficult to get a chargeback on misspent funds. Ideally, the Venmo payment process should be as pass-through as handing someone in front of you exact change, but it’s still not there.

“Smart appliances” tend to be even less pass-through. Anyone who’s purchased a recent model washing machine touted for its high-tech features will be confronted by an incredibly complicated interface to replace a once-easy UI, where several settings must be selected before executing a simple task.

“Conceptually,” as my colleague Dr. Michael Zargham puts it, “we can ask whether automations actually save us attention. If they don’t, maybe they are not so smart after all.”

A classic xkcd comic about a frequent desire to automate a task, with the assumption that the automation might save more time than simply completing the original task. https://xkcd.com/1319/

This could also be expressed as a misunderstanding about the functionality of the interfaces on vintage (dumb) appliances. Mechanical devices are often very manual but also quite pass-through. For instance, turning a dial on a vintage dryer is fast and easy, especially after you’ve done it twice. “To this day,” as Michael observes, “I spend way too much time ‘configuring’ my smart dryer.”

Even though our computers are now better than 15 years ago (according to a University of Copenhagen/Roskilde University study), they still malfunction/fail to perform the tasks we want done 11%–20%. In other words, we are wasting up to 20% of our time on computers trying to learn the complex interfaces embedded within them.

Designing them to be as pass-through as possible is crucial — not just to help us be more productive and efficient, but to enrich our time. A pass-through UI helps create a sense of effortless flow, of being in what Greeks called Kairos time, where we’re perfectly in the moment. (As opposed to the clock-watching tedium of Chronos time.)

A pass-through UI checklist

A “pass through” interface is one which allows the human to access the capabilities directly to put them to use for the task at hand — focusing on the task the human is putting it to, NOT on the object itself.

For every function on a user interface, ask:

  • Always ask if the UI focuses more attention on the object of use itself (a pencil) or the use context/core task (writing). A successful pass-through UI increases attention on the context and away from the object itself.
  • Does it distract us from the core task? If so, remove or minimize it.
  • Does it immediately engage the core task? If so, consider removing intermediary functions.
  • Does it quickly convey its relationship to the core task? If not, make it so.
It takes quite a bit of time to learn to ride a bike but we don’t have to re-learn it if we don’t ride for a longtime. We might get on a bike 5 years later and still remember how to use it.

Again, pass-through UIs are not necessarily beautiful or easy to learn, but they feel amazing to use once you’ve learned them, and understand they offer extra human affordances!

Learning to see and design with a pass-through mindset is itself challenging, but incredibly rewarding. Especially if we want to build the next generation of technology — and harmonize with, appreciate, and learn from the old.

Thanks to Dr. Micheal Zargham for reviewing this post.



Amber Case

Design advocate, founder of the Calm Technology Institute, speaker and author of Calm Technology. Former Research Fellow at MIT Media Lab and Harvard BKC.