I missed something somewhere. What is the McGuire Hump of the Horstman Curve?

I think I've got that the Horstman Curve is the painful process of learning and growing, per this other comment elsewhere on the forum:

"You are experiencing personal growth. It's like in the movies where somebody gets turned into something else - the transition is always shown as PAINFUL.That's just "The Horstman Curve" in action. ;-)"

But what's the "McGuire hump?" And who is this poor bloke McGuire?