These are controlled from the model file and I don't think it is advisable for you to hack these files. There are 2 methods that is responsible in retrieving the fields:
/administrator/components/com_easysocial/models/users.php
Look at the method getAbout . This method would call the fields model to retrieve the fields
/administrator/components/com_easysocial/models/fields.php
Look at the method getCustomFields
Alternatively, I would suggest that you edit the template file instead to control the behavior of the fields, /components/com_easysocial/themes/wireframe/fields/about/default.php