For example in my Asian culture, mom, dad, uncle, aunt, ... All live together. We help take care of kids other than our own direct offspring. So we're less stressed, work harder, therefore our boss sees us as more valuable with more energy. We can therefore take on more responsibility, doing more than asked.
Although we might have the same title, when you show enthusiasm, employers are bigoted like that and pay you more.
Stats don't take into account enthusiasm. If they did a study based soley on how enthused you are about a job compared to pay.
Most jobs aren't based on widgets made or sold. But those like commission, and tip based servers, the more enthused you are, the more tips and commission you make. Even though not on those stats, I'm sure happy workers who do more, aren't late, and show innitative to go above and beyond, get rewarded with higher pay.
The closest I could find to that hypothesis is this.
"The fairness-based salary is partially significantly correlated to psychological contract, indicating employees care about reasonable salary mechanism, motivating human resource strategy, appropriate reward system and available communication channels. When employees sense their salary is lower than the market average, they will have unsatisfactory feelings, make less effort to the organization and feel tired or want to leave the job."
https://www.tandfonline.com/doi/abs/10.1080/09603107.2013.829197
“emotional labor” to describe the curious situation where “seeming to love the job becomes part of the job.”
https://www.fastcompany.com/3005419/why-faking-enthusiasm-latest-job-requirement
"If Asians Make More Than Whites Then What Should We Do About The US Racial Pay Gap?"
https://www.forbes.com/sites/timworstall/2015/12/30/if-asians-make-more-than-whites-then-what-should-we-do-about-the-us-racial-pay-gap/#22d1b9c2457b
How do you fake at a job if you're tired all the time and have a negative attitude on life?
Seems there's more to it than...