From Jigsaw to good old Freddy Krueger, the mere thought of certain horror characters is guaranteed to send an icy chill down the spine. But how does Hollywood manage to produce horror icons that can petrify even the hardiest of us?

Arguably it's all to do with our more basic instincts. Join us a we take a quick, highly unqualified look at the psychology behind our most terrifying horror heroes and why it is that they make us tremble in our boots!