I want to know the answer to the following question:
People favoring those in their group over outsiders, is an example of what?
All the background I'm provided with is that "Another issue that researchers have attempted to address is the question of why people engage in discrimination, i.e., why they tend to favor those they consider a part of their "in-group" over those considered to be outsiders.". Is that enough to answer the question?
Answer: yes