Linux

Generally it's more about the interaction. If the user views it as interacting with the viewport, it tends to be inverted. If the user views the interaction as interacting with the scroll bar, it's "natural". Scroll wheel is the only odd one out. However it was introduced prior to mousepads supporting gestures. So it basically started as an extension of the scroll bar interaction, but as mousepads introduced the concept of interacting with the viewport, scroll wheels were given the option to respond either way based on user preference.

At work I sometimes switch the scrolling over to traditional. Others get completely thrown out and cannot grok it! 😂

I noticed this in video games rather than on-screen text scrolling. Some of them had a weapon selection, but instead had mouse-wheel-down "decrease" the weapon slot, and mouse-wheel-up "increase" it. However, the game also used the mouse wheel for other things, thus changing it to my preference had some unexpected side effect.

In any case, mouse-wheel to scroll view works because of the mouse-pointer paradigm. Move both mouse-wheel and mouse in the same direction, and the pointer is further along the content. Move them in opposite directions, and the pointer tends to hold position relative to content.

Natural, but I use a touchpad.