There is some IOR happening, but because its such a dark render it doesn’t show up too well. I have done several other renders which show a good amount of refraction of the wallpaper behind, but they expose other weaknesses in the image. Like the fact that the wallpaper is tiled badly :). I have spent several nights trying to get the right balance of lighting and materials and its starting to wear on my patience.
I left the spec low purposefully…the lavalamp is supposed to be the main source of light in the room, and so specularity would only show up if there were other light sources. There is a small amount of HDRI reflected just to give some depth to the metallic rings above and below the glass.
I also tried playing with Radiosity last night and found that the emitting objects tend to blow out the image and without the proper diffusing of light by a physically accurate oily liquid it is very hard to match a lavalamp. I didn’t have the willpower to try adding actual liquids to the lamp - in fact the glass itself is faking the appearance of there being liquid inside. The glass is a transparent orange material with filter set high.