I don't have research for you off the top of my head, but here's anecdotal support -- there's no way these people can get this good at their tedious menial jobs[1] without finding a strong (superlatively strongest in the world) intrinsic motivation to perform better.
As Lewisham puts it, structure to maximize enjoyment of their intrinsic games is the best. Ideally, find out directly from the employees (or by being them for a while) what intrinsic games they play for their tedious tasks, and then try to build structure around making it more fun -- there's essentially 4 parts to it - holistic goals, performance stats, realtime feedback (these 3 are mentioned by example by Lewisham), and the hardest-to-implement, fun interactions.
The last is complicated, but for example, it's the reason why a clickety mechanical keyboard may be more fun to type on than one of those polymer rollable keyboards, if you have an employee whose job is to type all day [you and me probably]. Sometimes workers find ways to turn their interactions with their work fun on their own (like those in [1]), but for the less intrinsically motivated, employers facilitating it can have a huge effect.
As Lewisham puts it, structure to maximize enjoyment of their intrinsic games is the best. Ideally, find out directly from the employees (or by being them for a while) what intrinsic games they play for their tedious tasks, and then try to build structure around making it more fun -- there's essentially 4 parts to it - holistic goals, performance stats, realtime feedback (these 3 are mentioned by example by Lewisham), and the hardest-to-implement, fun interactions.
The last is complicated, but for example, it's the reason why a clickety mechanical keyboard may be more fun to type on than one of those polymer rollable keyboards, if you have an employee whose job is to type all day [you and me probably]. Sometimes workers find ways to turn their interactions with their work fun on their own (like those in [1]), but for the less intrinsically motivated, employers facilitating it can have a huge effect.
[1] http://www.collegehumor.com/post/6319342/goodatjobs