I don’t know if anyone else ever had this problem, but it just happened to me today. The mouse scrollwheel direction to zoom was suddenly set to reverse. Nobody has used my laptop but me and I have not messed with preferences for a long time.
Anyway, I figured out how to change the direction by going to:
Preferences > View > Scale Factor > changed it from 0.90 to 1.10
In case anyone else had this happen to their Mac version of Rhino, this is the solution. I am absolutely not sure why this has happened, but it has. Is there any known case of the software reversing this by itself? I honestly got nauseated from the effect as my brain was expecting the zoom to work differently. As in being sick from sitting in a car and looking at your smartphone.