Hard to say for certain. Though I do think it goes both ways. People at the bottom influence culture from bottom up, folks at the top from the top down.

> I do think it goes both ways

If we flip the snake so it goes along the political spectrum, with the biting ends being extremists, I suppose the fish does rot from the heads. Top-down versus bottom-up is a more-complicated situation, and I suspect it's closer to turbulence than anything monotonic.