User interfaces are disappearing before our eyes. It’s hard to find a phone with any actual buttons on it, touch-based tablet devices are displacing laptops with keyboards and trackpads- examples of this simplification are everywhere. There are kinesthetic and ergonomic reasons to favor user interfaces which require less effort to reduce the risk of repetitive motion injuries, to facilitate new ways of navigating the digital world that are more tuned to natural motions. The simplification of the user interface (graphical and physical) makes for an aesthetically considered and intuitive user experience. Also, as the physical profiles of UIs are simplified, they add mechanical versatility. The mechanical limits of a gesture interface are those of the user, and most user’s bodies are capable of many more kinds of movement than a mouse or touchscreen can register. There’s an obvious relationship between the mechanical versatility of an interface and its capacity to adapt to new tasks; you can’t conveniently perform robotically assisted remote surgery with a light switch. But how much is not enough? Consider for a moment the 1963 Jaguar XKE’s user interface:
This is a user interface that has evolved to accentuate the experience of manipulating an analogue device. There are a known number of controllable variables (throttle, brake, clutch, gear selection and wheel direction, in addition to a variety of interior climate controls and peripheral safety systems). The engineer can identify all of the mechanical and kinesthetic parameters, and through a series of iterative tests design a user interface which the majority of drivers will find intuitive, and pleasing to use. The key here is that the experience be physically satisfying- anyone who has ever absent-mindedly clicked a retractable ball point pen knows the visceral satisfaction of cycling a crisp mechanical device, like pushing the stickshift into fourth gear as the engine hits 4500 rpm. The XKE’s shifter provides a direct mechanical link to the gearbox. Through a linkage of rods, joints and bearings, it allows the user to feel what is happening in the transmission. The driver can’t literally manipulate the gears by hand, but using the shifter he or she can “virtually” reach inside the metal box full of spinning gears and shafts and alter its operation. The resultant experience is pleasing and visceral. The feel of a gear shifter has traditionally been one means of evaluating the overall quality of a sports car.
Humans are, among other things, physical entities. Our bodies respond to mechanical feedback. We can sense the quality of an object, especially a mechanical one, by manipulating it. Consider the transmission user interface from a contemporary racing vehicle, wheel mounted “paddle shifters:”
This is an electro-mechanical device, designed to facilitate efficient gear changes. The physical paddles communicate upshift and downshift commands to the electronic transmission- mechanical actions now performed in fractions of a second- a dramatic improvement in measurable performance. But actuating a gear change with this device conveys little or no information on the quality or state of the transmission itself. Flipping the paddle feels the same, whether the car is turned off or moving 150 miles per hour. The shifter and gears are connected by copper wire and electrons, and our bodies have no intuitive way to feel the connection. From the perspective of user experience, this UI might be an example of “not enough.” As these kinds of transmissions have become more pervasive in consumer vehicles, traditionalists have bemoaned the loss of the visceral experience of shifting.
It doesn’t have to be this black and white, of course. One way or the other, the connection between the driver and the gearbox (whether it’s rods and joints or wires and electrons) separates the person from the machine. Success of failure is all about how the designer considers the user’s experience. There’s no reason that haptic responses couldn’t be built into the paddles- the feel of the shift could be made communicative and invigorating. Efficiency can be fun. The same is true for digital user interfaces. Increasing percentages of our lives are spent interacting, in one way or another, with digitally encoded information. The degree to which these experiences are satisfying, to our bodies as well as our intellects, affects our quality of life. Ongoing efforts to untether us from our mice and keyboards promise to open new frontiers in the exploration of content, but as these technologies are developed designers should consider mechanical feedback as an important part of interaction with a machine.
—Daniel S. Meyers, Designer