Interesting article, but it doesn't really answer the question.
The one common theme in the personalities of liberals in my acquaintance is fear at various levels (social, economic, safety, health, etc.).
On the contrary -- I nominate that the one common theme is smugness, arrogance, self-righteousness, and an annoying belief that the state is superior to the individual.
Please explain what you mean by fear because I have yet to meet a liberal that is fundamentally afraid.