This isn't new, and I know the story but hadn't seen the video before and I love the reaction in the picture!
If anyone else is concerned about the impacts of pay differentials and income inequality on social capital, I recommend a book I read fairly recently, Sam Pizzigati, the case for a Maximum Wage. This isn't as fact based as Spirit Level but is possibly even more compelling (to me at least) suggesting that inequality exacerbates status differences and leads to dysfunctional behaviour when trying to catch up.
"Some organisations are already taking steps to create a solidarity environment where all employees feel rewarded - and enthusiastic about contributing to the enterprise's success." - I think Gravity Payments sounds like a great example of this.
Thanks Kevin Osborne for the tweets from the I4CP conference.