A View from Christopher Mims
How to Make Fake Buttons Feel Real
Virtual buttons on touchscreen interfaces that vibrate in ways that fit our expectations for real buttons could increase usability
As touchscreens replace actual buttons, what are we losing? Can it be recaptured? It turns out that making touchscreen technologies like smart phones vibrate in a particular way can fool our brains into thinking that fake buttons are in fact real.
The key technology is piezoelectrics, which move in response to an electrical charge. More sophisticated than simple vibrating motors, they allow researchers fine-grained control over frequency, duration and onset of a vibration – all of which turn out to be essential to fooling the brain into thinking that a virtual button has the satisfying “click” of a real one.
Recent work from researchers at the University of Tampere, in Finland, explored the preferences of users for different lengths of delay between touching a button and vibration, as well as the subsequent duration of the vibration.
Intriguingly, preferences seem to track what we’d expect from real-world buttons: interfaces that vibrate soon after we click a virtual button (on the order of tens of milliseconds) and whose vibrations have short durations are preferred. This combination simulates a button with a “light touch” – one that depresses right after we touch it and offers little resistance.
Users also liked virtual buttons that vibrated after a longer delay and then for a longer subsequent duration. These buttons behaved like ones that require more force to depress.
Just about every other combination of onset and duration fell into some sort of “uncanny valley” of button perception, and were not preferred by users.
Research shows that so-called “haptic” feedback (tactile, vibration, etc.) improves accuracy and usability on touch-screen interfaces. Research has also shown that the appearance of a virtual button informs a users’s expectation for its behavior.
Combined, these features seem certain to lead to a new kind of usability design, in which interfaces are not merely virtual but regain some of their physicality.