What a load of ****, its not human nature to get yourself hurt, if anything its the complete opposite.
You obviously don't know much about psychology. Go have a read up before saying what I'm saying is bull. The human brain is capable of a lot, and safe guards are there to prevent a lot. Thoughts you should not have are human nature, The reactions to those thoughts are also part of human nature. And people with problems unfortunately dont always have the correct reactions. The correct action is not to jump obviously, But the urge still manifests in some, especially those with no fear of heights.