http://science.sciencemag.org/content/356/6334/183.full

“Our results also suggest a null hypothesis for explaining origins of prejudicial behavior in humans, namely, the implicit transmission of ingroup/outgroup identity information through language. That is, before providing an explicit or institutional explanation for why individuals make prejudiced decisions, one must show that it was not a simple outcome of unthinking reproduction of statistical regularities absorbed with language. Similarly, before positing complex models for how stereotyped attitudes perpetuate from one generation to the next or from one group to another, we must check whether simply learning language is sufficient to explain (some of) the observed transmission of prejudice.”