[NeoCaveman]

tro·pism ( P ) Pronunciation Key (trpzm)
n.
The turning or bending movement of an organism or a part toward or away from an external stimulus, such as light, heat, or gravity.

Nah, I think it began with an h. This is going to bug me.

[ALWAYSWELDING]

I think the AllButtCrap network was Rather wrong. Nice try you flamin liberal bleeders.

[lugsoul]

It was tropism. I learned a new word from MoDo, right here on FR. Here's another def that comes closer to the one I saw right after:

n : an involuntary orienting response; positive or negative reaction to a stimulus source