What is a scientific explanation for why some people enjoy watching horror movies?
5$\begingroup$ This question does not meet our standards of initial research since it is easily answerable by the obvious search query (like 'appeal of horror films'). This SE is for scientific questions about psychology, neuroscience, and other cognitive sciences, as such we expect our questions to be informed and framed in a scientific way when possible. $\endgroup$– Artem KaznatcheevSep 11, 2012 at 15:05
$\begingroup$ Thanatos, I had to close your question as it was too broad for this site and as Artem mentioned, it doesn't meet our initial research standards. Please don't be discouraged! You received a fairly good answer; please do research this further and ask more detailed followup questions (or totally unrelated questions) $\endgroup$– JoshSep 12, 2012 at 13:15
Certain emotions/situations trigger parts of body's self defense mechanism which in turn make the brain release certain chemical compounds.
These chemical compounds in turn prepares your body to respond to the situation at hand. For example in case of life threatening situation one experiences an adrenaline rush which prepares the body by quickening the heart rate and adding strength (sometimes perceived as almost superhuman) and speed to our usual abilities. This lets an individual fight to the best of his ability or run away as quickly as possible.
As a side effect of adrenaline, the body releases dopamine which (among its many uses) stimulates the brain's pleasure system.
Thus when you experience a 'fear' moment in a horror movie, your brain perceives it as a threat and triggers and adrenaline rush which in turn releases dopamine.
Further reading: Adrenaline rush, Dopamine functions