So i placed a piece of wood on the exterior of dry wall and screwed it in with regular wood screws?

So i placed a piece of wood on the exterior of dry wall and screwed it in with regular wood screws, then i my object to the wood and it acted like a stud. Why is that?

I didn't use any anchors, but when i pull on it its as secure as it would have been if i mounted it to a actual stud in the wall.
8 answers 8