Any comment on lemmings being suicidal in popular culture is incomplete if it doesn't credit Disney for chasing a few of the "nasty little rodents" off a cliff.
I did like that note in the post "In the popular imagination, for some reason, we interpret this as consistent and collective suicide."
Where "some reason" is because TV told us so. I wonder where the original myth came from. Obviously the population fluctuation gave rise to it - but someone decided they were committing mass suicide. I'd love to know how much of a "fact" it was before the Disney piece.
http://www.snopes.com/disney/films/lemmings.asp