Studies going back over 50 years have repeatedly arrived at the same conclusion — racists have lower IQs than non-racists. The average intelligence quotient (IQ) of all members of the human race is 100 on the Stanford-Binet scale, as illustrated in the bell curves in the figure below. The average IQ of racists is up to 4 IQ points less than this.
The reasons this is true are not entirely clear. Does racism attract the unintelligent or do the unintelligent default into racist mentalities?