IQ is not an objective measure of intelligence. Nothing is. Intelligence is a colloquial and subjective concept like beauty, wit, or BDE. The idea that any of those things can be objectively measured is a logical fallacy. It was developed by eugenicists to do eugenics.

In his book, the 'Mismeasure of man', Gould wrote that he's often encouraged to compare IQ testing to phrenology. But he says that comparison isn't fair... to phrenology. We all know that phrenology's methods are bunk, but it's theory, that different regions of the brain are responsible for different functions is still mainstream neurology. IQ testing fails in both methodology and theory; phrenology is a superior instrument.

Any research based on IQ testing is suspect and unreliable.