Graphical artifacts from lighting

My game objects have some sort of artifacts showing up on them, even on a simple plain white cube like I have shown. From what I can tell, it is an effect of the lights, and especially combinations of lights hitting the objects at different angles. A single light source does cause ‘banding’, but multiple lights cause these odd fractal shapes. Does anyone know how to combat this? I’ve played with graphical quality settings but I can’t seem to fix it.

Here are two images. The second has higher contrast to make it more obvious what I’m talking about.

8422-artifacts2.png

I’m wondering if the mesh resolution of the box is at fault. I would try importing a slightly higher density mesh and see what happens.