Broockman, D. E. (2013), Black Politicians Are More Intrinsically Motivated to Advance Blacks' Interests: A Field Experiment Manipulating Political Incentives. American Journal of Political Science. 57(3): 521–536. doi: 10.1111/ajps.12018
Why are politicians more likely to advance the interests of those of their race? I present a field experiment demonstrating that black politicians are more intrinsically motivated to advance blacks' interests than are their counterparts. Guided by elite interviews, I emailed 6,928 U.S. state legislators from a putatively black alias asking for help signing up for state unemployment benefits. Crucially, I varied the legislators’ political incentive to respond by randomizing whether the sender purported to live within or far from each legislator's district. While nonblack legislators were markedly less likely to respond when their political incentives to do so were diminished, black legislators typically continued to respond even when doing so promised little political reward. Black legislators thus appear substantially more intrinsically motivated to advance blacks’ interests. As political decision making is often difficult for voters to observe, intrinsically motivated descriptive representatives play a crucial role in advancing minorities’ political interests.
Link to article here.