I haven’t used 3D Touch much since it was introduced on the new iPhone 6S this fall. 3D Touch, for those who haven’t used it, is a feature that relies on pressure from your finger and a combination of built-in hardware and software on the new phone to show shortcuts or offer "peeks" of content from apps. It is technologically impressive, but minimally useful: I’ve used it to Shazam songs, upload stuff to Facebook, and search Mail, but that’s about it.

This isn’t because there aren’t enough apps that support it; a search in the iOS App Store reveals a couple hundred well-known apps that include 3D Touch features, and Apple says there are many more. I don’t use it much because right-clicking on an app or having content pop out at me isn’t always more efficient. A deeper interaction still requires you to be fully in the app. Plus, I often Spotlight search for apps on the iPhone, and 3D Touch doesn’t work in Spotlight search results.

But a few new apps are using the pressure sensitivity of 3D Touch in different ways, beyond just quick actions and peek and pop, and point to a whole new realm of possibilities for 3D Touch. This is where pressure sensitivity on the phone gets really interesting.

At Johns Hopkins University School of Medicine, a team of doctors and researchers has launched a $1.99, 3D Touch-enabled game for iPhone called Bandit’s Shark Showdown. Despite its Pixar-like name, the app is part of a serious experiment; the group, which is lead by neuroscientist and neurologist John Krakauer and was recently the subject of a profile in The New Yorker, wants to see whether the pressure-sensitive touchscreen can help stroke patients regain dexterity and strength in their hands. About 65 percent of people who suffer a stroke lose use of their hands, Krakauer says, and most therapies teach stroke rehab patients to compensate for the lack of movement, rather than encourage them to reprogram the brain.

The premise of the game is fairly simple: by applying varying levels of pressure to the iPhone’s touchscreen, game players control the speed and force with which the game’s animated dolphin protagonist gobbles up sharks. "The more force you apply with your hand, the less dexterity you have with your hand," Krakauer says. "You want to stress the dexterity requirement at higher levels of force. And this force sensor allows you to play into the trade-off between force and dexterity."

Can a 3D Touch app help stroke rehab patients recover dexterity and strength in their hands?

Krakauer and Omar Ahmad, the department’s director of innovative engineering, are quick to point out that that they build and test a variety of solutions for stroke rehabilitation, and are "technology agnostic." Right now, the iPhone app only is part of a pilot study to determine efficacy. Still, Ahmad says, the dynamic range of the 3D Touch sensor surprised him, and in a good way. "I would love to see it on the iPad Pro — imagine if a patient could stretch an entire hand out on it."



There are also plenty of apps in the creative space that are now using the concept of "force" to trigger specific actions in painting or music production. In the app Procreate ($5.99) users can now intensify drawing strokes using pressure. Same with the app Pixelmator. A $10 music-making app called iMaschine 2 lets you change the velocity or pitch of a note, again, by applying pressure to the phone’s touchscreen. Apple’s own Garage Band app will soon support 3D Touch and will simulate an electronic keyboard with polyphonic aftertouch, which uses sensors in each key to adjust sound based on pressure.

Not surprisingly, game makers are starting to take advantage of 3D Touch too. The free iOS game Breakneck, for example, offers more nuanced control through pressure sensitivity as you’re flying an aircraft through a series of obstacles. And in one maps app, Poison Maps, you can now press to zoom in and out of maps.

To be sure, some of these apps — like the Johns Hopkins example — are much more ambitious than others in their utilization of 3D Touch. But they all are also inherently more useful than simply pointing toward the next thing you might want to do in an app.

The initial batch of use cases we saw for 3D Touch felt like a technology solution in search of a problem; we all learned how to navigate touchscreen apps without having a right-click or content preview option, so suddenly having them felt in a strange way like trying to re-learn something. But software that sneaks pressure-sensitivity into behaviors and motions that are already ingrained in us feels like the most natural evolution of 3D Touch, and a much better showcase for what this tech could actually be.