How to Adjust Your Mac Mouse
The Mac OS X Mountain Lion Mouse System Preferences pane is where you set your mouse speed and double-click delays, which are two more ways in which you can tweak your Mac workspace to suit your preferences.
If you use a notebook Mac, you may see a Mouse icon in the System Preferences application, but unless you have a mouse connected via USB or Bluetooth, it will just sit there searching for a mouse.
The first item in this pane is a check box: Scroll Direction: Natural. If scrolling or navigating in windows feels backward to you, try unchecking this box.
Moving right along, here are the features you’ll find in the Mouse System Preferences pane (if you have a mouse connected):
Move the Tracking Speed slider to change the relationship between hand movement of the mouse and cursor movement on-screen. This slider works just like the slider for trackpads.
The Double-Click Speed setting determines how close together two clicks must be for the Mac to interpret them as a double-click and not as two separate clicks. Move the slider arrow to the leftmost setting, Very Slow, for the slowest. The rightmost position, Fast, is the fastest setting.
If your mouse has a scroll ball or scroll wheel, you also see a Scrolling Speed slider, which lets you adjust how fast the contents of a window scroll when you use the scroll wheel or ball.
If your mouse has more than one button, you see a pair of Primary Mouse Button radio buttons. These let you choose which button — left or right — you use to make your primary (regular) click. Conversely, the other mouse button (the one you didn’t choose) becomes your secondary (Control or right) click.
This is a setting many lefties like to change. Set the primary button as the right button, and you can click with the index finger of your left hand.
In the following figure, the opposite has been done: the left button is set as the primary and the right button as the secondary (Control or right) click.
Changes in the Mouse System Preferences pane take place immediately, so you should definitely play around a little and see what settings feel best for you. You can test the effect of your changes to the Double-Click Speed setting in the Double-Click Here to Test text box just below the slider before you close this Preferences pane.