Source for that?

https://en.wikipedia.org/wiki/Minnesota_Transracial_Adoption_Study

Lefty source even. It's funny, you can tell everything you need to know by the conspicuous omission of the 1976 results from the introductory paragraph.

you'd be admitting that jews are smarter than white people.

They likely are. Using my same reasoning process about selection pressure, the jews have had no homeland for most of their existence. They've existed by infiltrating and manipulating other cultures, living off of them parasitically. Being found out or expelled from the host society leads to great suffering and death for them. That puts a huge selection pressure on the ability to manipulate and maintain a complex network of lies. That takes intelligence. It also leads to elevated neurotic behavior and psychological illness, which has been medically documented amongst the jews.

I try not to avoid the truth just because there are unfortunate conclusions.