Materials are colored differently on rotated objects

I have applied the same material to both, but as you can see the color is different. This seems to be true for anything that I rotate. I want them both to be the same color.

Why does this happen and how do I fix it?

NOTE: This seems to occur for many different materials, not just this one. There are lots of materials which don’t have this problem, but there are a lot of materials that do.

Do you still have the standard directional light on in your scene?

The problem seemed to be that my skybox was my source of light. I fixed this by going to

Window->Lighting and changing light source to color, and setting the color to white.