In Peter Godfrey-Smith’s book Other Minds, he cites work from 1950 by the German physiologists Erich van Holst and Horst Mittelstaedt.

They used the term afference to refer to everything you take in through the senses. Some of what comes in is due to the changes in the objects around you — that is exafference… — and some of what comes in is due to your own actions: that is reafference.

Peter Godfrey-Smith, Other Minds, p.154

Godfrey-Smith is talking about octopuses and other cephalopods, but I think what he’s discussing is interesting from a digital note-taking point of view.

To write a note and read it is to create a reafferent loop. Rather than wanting to perceive only the things that are not due to you — finding the exafferent among the noise is the senses — you what you read to be entirely due to your previous action. You want the contents of the note to be due to your acts rather than someone else’s meddling, or the natural decay of the notepad. You want the loop between present action and future perception to be firm. Thus enables your to create a form of external memory — as was, almost certainly, the role of much early writing (which is full of records of goods and transactions), and perhaps also the role of some early pictures, though that js much less clear.

When a written message is directed at others, it’s ordinary communication. When you write something for yourself to read, there’s usually an essential role for time — the goal is memory, in a broad sense. But memory like this is a communicative phenomenon; it is communication between your present self and a future self. Diaries and notes-to-self are embedded in a sender/receiver system just like more standard forms of communication.

Peter Godfrey-Smith, Other Minds, p.154-155

Some people talk about digital note-taking as a form of ‘second brain’. Given the type of distributed cognition that Godfrey-Smith highlights in Other Minds, it would appear that by creating reafferent loops that’s exactly the kind of thing that’s happening.

Very interesting.