In-group vs. Out-group

I developed the GNT method for creating in- vs. out-group distinction by asking the randomly divided groups to come up with a group name that they like in common through chat. They are instructed to come up with a name that belongs to one of the categories described below:

•  activities/hobbies that you and your group members all like
•  places/cities that you and your group members all like
•  persons/animals that you and your group members all like
•  objects/food that you and your group members all like

With the five minutes chat, my previous experimental results have shown that it effectively led to in-group favouritism.