(One possible reason why lectures are still so common: It is a cheap teaching method that scales well with class size.)
So to answer your concerns I tracked down the publication in PNAS: http://www.pnas.org/content/ea...
To quote from the article:
The data we analyzed came from two types of studies: (i) randomized trials, where each student was randomly placed in a treatment; and (ii) quasirandom designs where students self-sorted into classes, blind to the treatment at the time of registering for the class
In other words, if I understand the article correctly, the authors only considered studies where active learning was contrasted with traditional lectures in the same course! Therefore it seems likely that active learning is a good idea, regardless of whether the topic is hard or easy. (By the way, active learning doesn't necessarily have to involve fun and games, although if a student, in general, doesn't think that learning is fun, perhaps he or she should consider doing something else...)
For the details, see http://www.autosec.org/pubs/cars-usenixsec2011.pdf. (Pretty scary reading. In this case they are also able to disable the brakes and they are also able to engage the brakes on only one of the front wheels for all sorts of "fun"...)
"When set to 1, the ALTINST bit in the FCR enables ex ecution of an alternate (not x86) instruction set. While setting this FCR bit is a privileged operation, ex ecuting the alternate instructions can be done from any protection level.
This alternate instruction set includes an extended set of integer, MMX, floating-point, and 3DNow! in- structions along with additional registers and so me more powerful instruction forms over the x86 instruction architecture. For example, in the alternat e instruction set, privileged functions can be used from any protection level, memory descriptor checki ng can be bypassed, and many x86 exceptions such as alignment check can be bypassed.
This alternate instruction set is intended for testing, debug, and special application usage. Accordingly, it is not documented for general usage. If you have a ju stified need for access to these instructions, contact your VIA representative. "
I have tried to find some details about this alternate instruction set but haven't been able to find anything unfortunately. (And I'm not so interested in this any longer as my remaining Via C3 machine is now only used for backups and does not require very high performance...) Anyway, I'm guessing that it didn't become very popular due to the fact that they kept the details secret.
Happiness is a hard disk.