On animal models its also demonstrated that sheer brute force often wins (ie both racism and rape is ok according to animal models).
The problem with using biological models, or nature-vs-nurture to justify behavior is that it reduces humans to animals and defy civilization as such, so it usually does not carry enough weight to bother with it in sociology discourse as it's too easily shot down from too many angles.
This study is interesting that it was conducted on humans, in recent toxic PC climate. It is of course carefully worded, ie "empirical study", "we don't know if its nature vs nurture etc", but it's easy to draw conclusions on your own with basic knownledge of statistics. Understandably nobody wants to spell out anything explicit and be labeled next Josef Mengele. But yeah, people are instinctively racist unless they rationally overcome that urge, just like one must suppress many other urges of our stupid animal lizard brain. Boohoo. News at 11. But don't say that on national TV.