An excerpt from Joseph Pelrine training material about Attractors:
The attractors are the things or people in the system that are attractive to others and that others get attracted to. By changing the structures of what people perceive as attractors in the system, you can change the dynamics of the system itself.
An attractor here can be an idea, a group or a single person i.e. because of his/her knowledge, expertise, popularity, charisma, authority, power. In a system is possible to add or remove and attractor, amplify the attractor (i.e. empowering, removing obstacles, adding...