Don Norman and Bruce Tognazzini (an original Apple HIG author) wrote a great article about this a few years ago. Here's the excerpt describing discoverability:

Don Norman and Bruce Tognazzini (an original Apple HIG author) wrote a great article about this a few years ago. Here's the excerpt describing discoverability: "Today’s devices lack discoverability: There is no way to discover what operations are possible just by looking at the screen. Do you swipe left or right, up or down, with one finger, two, or even as many as five? Do you swipe or tap, and if you tap is it a single tap or double? Is that text on the screen really text or is it a critically important button disguised as text? So often, the user has to try touching everything on the screen just to find out what are actually touchable objects" Article here: https://www.fastcompany.com/3053406/how-apple-is-giving-design-a-bad-name https://www.fastcompany.com/3053406/how-apple-is-giving-desi...