A second group of explanations suggests that " coethnics " work together more effectively because they understand each other better or can ostracise shirkers .
第二类解释表明“同种人”合作更有效，因为他们彼此更加了解，或者可以排斥逃避者。
Dilma rousseff , the president , has form in hectoring private firms she sees as shirkers : earlier this year she attacked banks whose interest rates were too high for her liking .
