I was running set of diffs using a graphical tool. I was fairly sure none of the files had differences, but I needed to check. For each diff it would come up with a dialogue saying “file A and B are binary equal”, with an ‘OK’ button.

If I had been using the mouse I would have had to hover close to where I expected the dialogue to pop up, then move to shut down the diff application before doing the next one.

With the keyboard it was “enter,ctrl-q,arrow-down,ctrl-d” - the only hand movement needed was between the enter and the down arrow key…It certainly feels faster. And the only mental pause was to check that the dialogue had come up - the same pause I would have had with the mouse.

This is why your hand just seems to “know” where all the light switches and door knobs are in your house. This phenomenon is sometimes called “muscle memory”, a phrase that tellingly gives credit to an organ other than the brain. The brain is really in charge, of course, but the term rings true because the actions seem to happen without conscious thought. This is the ultimate in efficiency, leaving the higher-functioning parts of the brain free to concentrate on the task, rather than on the operation of the tool required to complete the task.