Proprioception is the body’s sense of where its parts are in space. Marcin Wichary borrows the term for software that knows where its hardware lives: where the buttons are, where the ports are, where the camera is. His proposed design principle:

The rule here would be, perhaps, a version of “show, don’t tell.” We could call it “point to, don’t describe.” (Describing what to do means cognitive effort to read the words and understand them. An arrow pointing to something should be easier to process.)

Wichary walks through a series of examples, mostly from Apple: the Apple Pay animation that points at the side button, the iPad camera prompt that points to the physical lens, Dynamic Island camouflaging missing pixels as a functional UI element. The one that caught my eye is the device Simulator matching the physical dimensions of your actual phone on-screen and staying accurate even when you change the display density. Reminds me of one of the earliest selling points of the Mac’s 72dpi—it matches the real world: 72 points to an inch.

The MacBook Neo is where Wichary applies the principle and finds Apple falling short. The new model has two USB-C ports with different speeds, and macOS notifies you with text:

I think this is nice! But it’s also just words. It feels a bit cheap. macOS knows exactly where the ports are, and could have thrown a little warning in the lower left corner of the screen, complete with an onscreen animation of swapping the plug to the other port – similar to what “double clicking to pay” does, so you wouldn’t have to look to the side to locate the socket first.