Like half of the world's population, I have a MySpace account.  On MySpace, your friends can post "bulletins" about whatever they wish to talk about.  Many are "surveys" which people fill out - they answer questions about themselves so that anyone who reads it can know the person better.

Now, another large portion of the total bulletins posted there are chain bulletins.  They take the same form as chain e-mails - "repost this or <insert whatever improbable horrible event you can think of here>".  So people repost this bulletin without hesitation.  The same goes for chain e-mails...but why?

Chain e-mails play on people's superstition and our basic human ability to make causal inferences and connections between events real, perceived and imagined.  The other ingredient is fear.  Just maybe, just maybe if I don't repost this bulletin or send this e-mail to everyone I know my mother will die at midnight!  Is it possible?  In the realm of probability, yes.  Is it likely?  Not at all.  You'd probably be more likely to be hit by lightening, be in a car accident or even hit by a meteor than that event perfect correlating with you not reposting that bulletin or sending that e-mail.

Another aspect at work in this area is something called attributional error.  With the e-mail or bulletin working as something called a "primer" people will be more likely to attribute any "bad" event to their non-compliance of forwarding that e-mail.  It's truly just a common psychological phenomenon and objectively there cannot be shown any link between whatever event might occur and not posting some e-mail.

All it takes is a little high effort thinking, understanding of the psychological principles at work and realizing that you won't have a horrible love life for 10 years if you don't comment on my blog.