Design of Everyday Things - Natural Scrolling

I’m re-reading Design of Everyday Things again - the team’s lead engineer wanted to have this book as our next team book club. It’s a great book and I read it earlier in my career.

In chapter 3, Knowledge in the Head and in the World, there is a discussion around natural mappings. One example in the chapter is motorcycle turn signals.

In the book club, one question that came up:

For those on macOS and use trackpads - what is the scroll direction? Natural or Un-natural?

This made me think: what direction do I even have it set as?? This setting is one that I set and forget, until I’m asked about it - like now.

I am one of the “natural scrollers” - where scrolling down on the trackpad corresponds with the page moving up.

Hmmm - how is that natural?! When moving in one direction, the reaction is in the opposite?? This mapping feels like a pulley - force exerted in one direction creates a force in the opposite direction.

🤔

Next I investigate natural scrolling mapping