Researchers conducted an experiment to solve the problem of free riders in group cooperation games. They introduced a leader support system where a leader could punish non-cooperating group members using support from others. The study found that leaders who punished both non-cooperators and non-supporters had higher cooperation and support from group members. These leaders also earned more profits because they received more support. This shows that effective punishment by a leader can increase their benefits and solve the issue of free riders in group cooperation games.