Humans haven't had multiple generations of selective breeding to select for particular cognitive traits. We have, however, had:
• Sunburn / vitamin D deficiency
• Oxygen deprivation at high altitudes
• Free diving
which have had obvious effects on certain human populations. But mentally, we're all pretty much just human, same as any other; variation is massive, yes, but it can be pretty big between siblings. Seeing “sheep dog breeds have a herding instinct” doesn't tell you much about humans.
When people try to argue a “genetic basis” for a particular trait, they're usually just trying to justify racism.
• Sunburn / vitamin D deficiency
• Oxygen deprivation at high altitudes
• Free diving
which have had obvious effects on certain human populations. But mentally, we're all pretty much just human, same as any other; variation is massive, yes, but it can be pretty big between siblings. Seeing “sheep dog breeds have a herding instinct” doesn't tell you much about humans.
When people try to argue a “genetic basis” for a particular trait, they're usually just trying to justify racism.