Helping people discover the invisible (3D touch)

Apple’s 3D Touch provides a new set of interactions, such as firmly pressing rather than tapping.  Unfortunately this is impossible for people to see and hard to discover.  This lack of discoverability is a general problem for gestural interfaces and critiqued by D. Norman and others.

Like many gestures that might be hard to discover, once discovered they can support seamless interactions that can avoid tricky design tradeoffs. One such tradeoff concerns making something easy to do, but making it hard to do by accident.  Avoid inadvertent activation often creates awkward interaction, such as having to press down and twist to open a pill bottle.

Apple may have chosen 3D touch with the ideas of forcing discovery and avoiding inadvertent interaction in mind.  The wake screen of the iPhone X includes icons for two common functions: camera and flashlight.  Taping these icons does not invoke them, you need to press firmly.  This firm press avoids accidental pictures and also teaches people about 3D touch, which might motivate people to try it elsewhere on the phone.  Forcing me to do a quick google search for how to use the camera has led me to discover other delightful aspects of 3D touch.