The cause of this seems highly separated from the topic of discussion (heritable intelligence) though. I think it is more than obvious that the main cause is selection bias; that is in general why immigrants in general often outperform those who already live there. If you have the drive, determination, and consciousness to be able to go through such a major life change, that itself says something about you. So this filter lets in only those who are talented in this regard.
This model makes the prediction that immigrants from countries that are harder to migrate from will be smarter than those who can migrate more freely. This is seen in the real world: As stated here, African immigrants to the US are currently one of the most impressive model minorities in the US. They beat out, say, Asian immigrants (who also overperform on average.) And Asian immigrants beat out, say, Canadian immigrants, who no one really claims are all that special or particularly distinguished (as migrating from Canada even easier.)
The cause of this seems highly separated from the topic of discussion (heritable intelligence) though. I think it is more than obvious that the main cause is selection bias; that is in general why immigrants in general often outperform those who already live there. If you have the drive, determination, and consciousness to be able to go through such a major life change, that itself says something about you. So this filter lets in only those who are talented in this regard.
This model makes the prediction that immigrants from countries that are harder to migrate from will be smarter than those who can migrate more freely. This is seen in the real world: As stated here, African immigrants to the US are currently one of the most impressive model minorities in the US. They beat out, say, Asian immigrants (who also overperform on average.) And Asian immigrants beat out, say, Canadian immigrants, who no one really claims are all that special or particularly distinguished (as migrating from Canada even easier.)