Have ideas of "gamification" been applied to education? Wikipedia defines Gamification as "the use of game design techniques and mechanics to solve problems and engage audiences."
Khan Academy has received attention (e.g., see this post) for incorporating some elements of gamification into its online learning system.

Are there any scientific papers that seek to:


integrate the ideas of "gamification" into models of education and cognitive psychology?
critically and empirically evaluate the ideas of gamification for educational purposes?
A popular lit review [1] discusses some game concepts that have been empirically tested to support the idea of gamification. In some cases, these may be very hard to quantify. For instance, the article cites fantasy as one gaming characteristic that engages gamers. Other characteristics, such as having clear, well defined rules/goals seem easier to objectify.

The authors also cite mystery, challenge (something hard but not too hard, with levels of increasing difficulty), sensory stimuli, and user control as important attributes as well.

[1] Garris et al. (2002). Games, Motivation, and Learning: A Research and Practice Model. Simulation and Gaming, 33, 441-467. Retrieved from http://scottsdale.brainadvantage.com/PDF/Games,%20Motivation,%20and%20Learning.pdf