Internal drive ?

Hi~ What could be the best interpretation of the phrase in red in this context?

And whose internal drive can it be? Teachers' or students'?

Thank you~

Let’s consider the climate established by standardized testing. It seems to meet all the criteria for creating an environment conducive for cheating. The adults who are supposed to instill ethics and be vigilant against
the act of cheating might not be as motivated as they once were. There is a fear of loss present; teachers in schools that don’t meet Adequate Yearly Progress risk loss of reputation, respect, and in some cases even employment. The emphasis on test performance placed on students no longer comes solely from parents and internal drive. With added pressure, students too are experiencing fear of loss, because more and more schools
celebrate improved test scores through some form of extrinsic rewards.