There’s always a bell curve, but the norm is set by the group. Plus, scores are not causative—they’re barely correlative. Many people far outperform simple scores and many “geniuses” underperform. A 105 IQ makes one a genius when the mean is 75.
Choosing mental and physical differences as the single cause.is as illogical as denying their existence.
Did you have a point? Beyond setting up a straw man in implying I asserted a “single cause” here?