Answer:
social identity theory.
Step-by-step explanation:
The social identity theory of the suggestion that an organisation can decide to change the behaviour of individuals if it can bring modifications to their self identity.
It gives specifications and predictions to the situations where people might see themselves as one person or as members of a group.
From this question, we can see that the participants to find themselves based on the group traits to which they belonged. Those that were shared into pulligand defined themselves based on those traits. And nulligans defined themselves based on the nulligan traits.