This is the logic behind the change in scrolling direction on the Mac. It is more “natural” to use the trackpad or the flat upper surface of the Apple Magic Mouse in this way.
Apple is slowly moving away from the mouse to the trackpad. This is a screen shot from the iMac page in the Apple Store. When we bought a new iMac a few weeks ago, we opted for the Magic Trackpad since both my husband and I are comfortable with trackpads in Apple’s portable computers.
If you don’t want to re-train your muscle memory (but you should), you can “fix” this behavior.
For the trackpad:
For the mouse:
There are more additions to mouse and trackpad behavior. Be sure to pay attention to the video lessons in the Mouse and Trackpad System Preferences.