Allowing her to normally jump on the couch or any other furniture w/out being invited to do so can definitely cause this. By allowing them to do so, they start to dominate the room. This is something I have a hard time with myself with Lexi. She LOVES to be on people's lap, just for attention. (shes not completely the affecionate type) As soon as she gets a lil pet/rub, on to the next person!

I have worked really hard on her only being allowed on the couch when I invite her ONLY. If she jumps up on her own, I just say DOWN! Shes done MUCH better! She will usually just look at me when she wants to jump up, or give me a paw. I have set up nice little spots in the livingroom floor where my dogs can relax and play and feel like it belongs to "them"
Just an idea!