This image shows the same room with the original four spot lights. There are no fill lights in this scene. It is rendered using the radiosity algorithm which takes into account bounced light.

Notice that the room has a lot of subtle gradations of light and shadow. There is a subtle darkening of the walls where they meet the floors, ceiling and each other. They are gently illuminated by the light bouncing

off of the floor and the sphere, not just by the direct illumination of the spots.

Also notice that the warm color of the wood floor is reflected throughout the room. The warm room color is not caused by adding color to the lights in the room, but only from reflection of the floor color.