I highly doubt that psychological underpinnings was the biggest factor preventing white men from going sub 10s in the 100m for 7 decades while Africans did it.. Is that the reason why such a higher percentage of black athletes than white can clear the 40" vertical in the NFL and NBA? Is there a psychological barrier preventing other races from beating Eastern Europeans in competitions of upper body strength? Is it a lack of belief in oneself that prevents a Chinese man from growing as tall as a man of another race? Seriously, people, if we only allowed science to explain things when they are perceived to be non-offensive to everybody, we'd still be following a geocentric model when studying astronomy. Great Danes and Chihuahuas are the same species, but they have vastly different attributes. Believe it or not, this stuff applies to people, too, and it's not limited to just melanin deposits in the skin.