Paul Gerrard and James Bach have recently blogged on testing schools, from two different viewpoints. I think both have relevant points though their views differ. Many testers learn their craft through osmosis, absorbing the testing culture of their organisations (or projects) and any external influences (mailing lists, conferences, user groups, training etc). In the absence of these external influences, the organisational culture can remain static and follow a certain orthodoxy (often aligning with a school of testing), sometimes with religious devotion. When I caught up with one of my initial testing mentors after 5 years, I asked her what she thought of exploratory testing and all the changes to the industry, but she had no idea of what I was talking about as she had stayed doing what she knew. So organisations can follow schools of testing, and so can the people within them if they have no interaction with external influences (or they choose to ignore them).