Editing lighting on the sides of a cylinder I'm creating a simple jar and lid in Cycles, but the sides of lid have this odd gradient effect I can't seem to get rid of. The highlights are only visible along the upper half of the sides. I'm not sure if I'm explaining it well, so here are a couple of images.

This is the effect I want:


And this is what I currently have:


Here's the node setup, in case it helps. I'm want a glossy plastic effect:


I don't know if this is a problem with the material, the lighting setup, both, or something else entirely.

Edit: I don't think my question is necessarily a duplicate of Glossy reflections and smooth shading. That question has more to do with creating reflections on an object with both flat and beveled surfaces. I'm trying to get the appropriate lighting on the side of a cylinder.
Out of curiosity, I added 2 edge loops to the cylinder, and that seemed to fix the problem I was having with the lighting. I've only been using Blender for a few weeks, so I can't explain why that fixed it, but it did.

The wireframe with the additional edge loops highlighted:


And now the lighting affects the entire edge.