Why OS X Mavericks changed the direction of scrolling?

I admit I was left puzzled after upgrading from Snow Leopard to Maverick. The first thing I noticed was that dragging two fingers towards me was not resulting in the scrolling (I also learned that this was added in Lion already). At first I thought that something went wrong with the installation and things were not working as they supposed to. I attached my mouse but scrolling the scroll wheel towards me was not working either?!? I could not scroll anymore!

Then I accidentally scrolled it in the opposite way (away from me) and it worked! After a few tries I realised that Apple has changed the direction of scrolling. But the question is not why! Rather, the question is why now.

If we take probably the oldest "scrolling screen" invented – the scrolling pergament as seen on the photo below, scrolling the upper stick away from us results in the scroll moving down. Scrolling the bottom stick towards us results in the scroll moving up.

(Photo courtesy: http://i620.photobucket.com/albums/tt284/malena_malena/a-scroll.jpg)

The touch screen interfaces (used on smart phones and tablets) use this concept. If we imagine that the sticks of the pergament are on bearings and fixed, dragging the paper down moves the pergament towards the top. The same way as dragging the finger down on the touch screens makes the e.g. web page move to the top.

The scrolling on Mavericks works the same way. It’s weird at first but I love it even though I have a hard time to scroll even after a day of use. Nevertheless, some concerns remain such as:

  • Users using Windows and Mac (separate machines) would find it hard to switch between different scrolling directions.
  • After a few decades of "unnatural" scrolling, would most users really want to switch to more "natural" way of doing it.

This move raises some questions as well.

  • Why was scrolling so far been "unnatural"? I have searched the web with no success. One possible reason I see is that the earlier way of scrolling (mouses with no scroll wheel) was to hold the scrollbar handle and move it downwards to go towards the bottom of the document. Introducing the scroll wheel kept the behaviour and scrolling it "downwards" (or towards us) moved the documents towards the end. The trackpads kept the same movement — early trackpads that supported such movements had a dedicated space on the right side of it resembling scrollbars. And I suppose the multi-touch Apple’s scrollbar kept the behaviour.
  • Why this sudden change? One possible reason is to keep the behaviour the same on touch screens and on desktop computers. But was this change really necessary? The trackpad/mouse interaction is to a certain extent different than the finger interaction on touch screens. Moving objects around is for example the same: point, click/hold, and move. While scrolling for me is not the same. I cannot map the "dragging the scroll wheel down moves the page of the document up" concept in my head. I cannot associate dragging two fingers over a trackpad with "holding the page document" as it happens with the touch screens. But maybe I’m just to used to the old model of doing things.  

Anyway, for the time being I’m sticking with this (for me at least) new concept. As scrolling has always fascinated me I have to experiment how it goes.

Edit 28. 10. 2013: Even my wife decided to stick with the new direction of scrolling. Her response to whether she wants the old behaviour or not was that she’ll get used to it. Even if she uses Windows at work. I’m curious.