On my Mac trackpad it's a 2 finger scroll to move up and down. Widening/Narrowing the gap between those 2 fingers (after briefly lifting off the trackpad) then performs a zoom in/out.
PC
I am almost convinced it's something I am doing with the mouse pad. Maybe the copious amount of alcohol. But then alcohol doesn't affect motor skills or cognitive functions so...
All that's left of what we were is what we have become.