All smart people know that sand niggers are retards. This can be easily observed through simple observation. Common sense can detect this fast and accurately. However, communist brainwashing from publicly funded communist camps (schools, colleges) can be a powerful thing in the negative. So for the brainwashed communist victim who needs proper scientific proof, here is all the proof you will ever need. Mix this with common sense and if you still cannot figure it out, go shoot yourself.