Proportional Editing and Laptop Problem

On windows, Use Pageup or Pagedown after pressing G until the you see circle comming up and move track pad pointer to adjust the required modfication

On Mac laptop you need to press Fn and scroll (two finger gesture) up or down.

Proportional editing effects all items within a sphere of influence. If the sphere is very large then everything appears to move the same amount.

The two standard methods of adjusting this size are mouse scroll wheel and page up/page down. For a laptop there is also a trackpad pan setup, I believe apple trackpads do panning with a two finger swipe.

If you still have trouble you can modify this shortcut yourself, you can find it by going to the user preferences->Input, down the bottom of the list there is a group called 'Transform Modal Map' expand that and you will find Increase Proportional Influence and Decrease Proportional Influence for both keyboard and mouse, you can change these to any key combination that works for you.