Testing vs. Teaching

There is a difference between testing and teaching and it looks like testing is more important:

Remember the dreaded pop quiz?

Despite their reputation as a cruel tool of teachers intent on striking fear into the hearts of unprepared students, quizzes -- given early and often -- may be a student's best friend when it comes to understanding and retaining information for the long haul, suggests new psychology research from Washington University in St. Louis.

"Students who self-test frequently while studying on their own may be able to learn more, in much less time, than they might by simply studying the material over and over again," says Henry L. Roediger III, Ph.D.

"Our study indicates that testing can be used as a powerful means for improving learning, not just assessing it," says Henry L. "Roddy" Roediger III, Ph.D., an internationally recognized scholar of human memory function and the James S. McDonnell Distinguished University Professor at Washington University.

Speculation: Could a similar phenomenon be responsible for the Flynn effect?
Another speculation: If teachers and administrators are afraid to give IQ tests to a certain minority group, would that lower the IQs of members of that minority group?