There is clearly some kind of an official group that has some sort of political role to play, which is popular in its character.

很显然需要有一个官方组织,扮演某种政治角色,从属性上来说这很常见

耶鲁公开课 - 古希腊历史简介课程节选

I think the answer is that both play a role but some of the effects are due to stereotypes above and beyond in-group favoritism.

我想两者都有,但刻板印象的影响,要高于组内偏爱。

耶鲁公开课 - 心理学导论课程节选

So, African Americans also are biased against African Americans and in favor of white Americans, showing it doesn't reduce to group favoritism though that probably plays a big role.

所以黑人也是,对黑人有偏见,倾向于白人，这样表明组内偏爱,所起的影响并不大。

耶鲁公开课 - 心理学导论课程节选