Research! The pyramid model isn't used exclusively for the food chain. It is useful in any case where you need a graphical representation of hierarchy.

I would argue that the graphical model representing the zombie food chain is only true within a certain scope of recorded zombie behaviour. Zombi 2 shark scene, anyone? I feel it important to note that in many a zombie movie or story, there is often some amount of deviation in zombie behaviour that throws off the surviving humans. Evolution of a classic storyline.

combined with electrode therapy, this could mean interesting developments in the area of . . . behaviour modification. imagine receiving a paralysing jolt every time you looked at a door. over time this could create prisoners mentally incapable of escaping. or imagine being shocked every time you looked at a child funny.