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.
This is very interesting. When we think of multimodal feedback needing to make cognitive sense, synchronization first comes to mind. But there are many more synesthesias in our experience that can only be uncovered through careful reflection. To make an interface feel real, we must first examine reality.