Apropos of the post immediately below, let me tell you a story. A college friend who earned a psychology doctorate at UC, Berkeley told me in confidence of a study in which he participated as a grad student assistant. He is long dead as are, I'm convinced, his faculty mentors so the story can be told.
The mentors had come up with a nonverbal step in human development which everybody passes at some point. What they'd discovered was the age at which that milestone was passed was inversely correlated with IQ. The higher the IQ, the younger the child exhibited that particular behavior.
Anxious to produce proof that there were no racial differences in intelligence, they tested preschool children categorized as white, black, Asian, and Hispanic. The hope was to show that any differences between racial/ethnic groups were insignificant and thus differences in IQ scores could be attributed to linguistic or cultural issues, not to race.
As you've probably guessed, what they found was entirely politically incorrect. The group rankings were exactly what the IQ tests showed. Asians exhibited the target behavior youngest, followed by whites, followed by Hispanics followed by blacks.
After spending probably 2-3 years on the study, and trying their best to find a way to put a positive spin on the findings, they finally gave up, and moved on to other topics. Having wasted much of his grad school time working on a study which was never published did my friend's career no good at all, and he was bitter about it.
This all happened roughly 60 years ago; taboo topics are nothing new.
