His contribution to social science is his focus on distributed information in economic production. Think about how decision-making is distributed in capitalist economies: bankers, investors, asset managers, producers, distributors, retailers, brokers, executives, corporate planning departments, middle managers, marketing departments, advertising, etc. Just imagine trying to replicate all that effort with a few office buildings' worth of planners in Moscow (Compare that to just Wall Street!). You can't run an economy without enough planners.
Hayek never tells jokes. I think if he had any sense of humor at all it might have occurred to him that designing the perfect society without planners (or much democracy) was certainly a kind of planning. He's like the whiteboard in "Office Space" that says "Planning to Plan" except it says "Planning to not Plan" and it's three books and 700 pages long ("Law, Legislation and Liberty").