Regarding the Sculpt tool (I'm using blender 2.70)

Hello. I’ve been trying to model a hair via mesh on my character, and I’ve seen a tutorial in which you actually make a plane, modify it, and then with ALT+D you duplicate the ‘hair strand’ and then keep modifying it more by will. The problem occurs right there, when i try to modify the mesh, it actually modifies all of the ‘hair strands’ at the same time, and not the one the brush is hovering above… Any ideas?

Alt+D creates a linked duplicate. Edit one and all the linked duplicates change as well
Sift+D creates an unlinked duplicate