The Touch Bar is an unusual way of interacting with a computer. Why a touch strip?

There’s a number of designs that we explored that conceptually make sense. But then when we lived on them for a while, sort of pragmatically and day to day, [they] are sometimes less compelling. This is something [we] lived on for quite a while before we did any of the prototypes. You really notice or become aware [of] something’s value when you switch back to a more traditional keyboard.

What were you trying to accomplish?

Our starting point, from the design team’s point of view, was recognizing the value with both input methodologies. But also there are so many inputs from a traditional keyboard that are buried a couple of layers in. We have that ability to accommodate complex inputs, mainly out of habit and familiarity.

So our point of departure was to see if there was a way of designing a new input that really could be the best of both of those different worlds. To be able to have something that was contextually specific and adaptable, and also something that was mechanical and fixed, because there’s truly value in also having a predictable and complete set of fixed input mechanisms.

Clearly, the function row seemed a good opportunity to explore.

As has always been the way, we develop designs as quickly as we possibly can. This is a particularly difficult prototype because it required a fairly mature software environment, and a fairly mature and sophisticated hardware prototype, to really be able to figure out whether these ideas were valuable or not. One of the things that remains quite a big challenge for us is that you have to prototype to a sufficiently sophisticated level to really figure out whether you’re considering the idea, or whether what you’re really doing is evaluating how effective a prototype is.

You say you needed advanced software and hardware before you even considered a prototype. How long has this been in the making?

I would guess that probably two years ago we had a pretty good prototype that wasn’t product specific. It was exploring this idea of larger, haptic-rich trackpads — what you now see as the Touch Bar combined with a keyboard. It certainly didn’t look particularly well resolved, but it created an environment where you could start to see: Is this as useful and is this as compelling as we conceptually think it should be?

This was an area of combining touch and display-based inputs with a mechanical keyboard. That was the focus. We unanimously were very compelled by [the Touch Bar] as a direction, based on, one, using it, and also having the sense this is the beginning of a very interesting direction. But [it] still just marks a beginning.

You sort of change your hat, because you have to figure out how do you then productize it, and develop the idea, and resolve and refine to make it applicable to a specific product. To do that in the context of the MacBook Pro — while at the same time you’re trying to make it thinner, lighter and more powerful — the last thing you want to do is burden it with an input direction that now has a whole bunch of challenges specific to something like touch.

You can become fairly comfortable that you have a design direction that’s compelling. But if you can’t work out how you can refine that [without] compromising the final product, you can still undermine a big idea.