From the Time magazine web site:
Kevin Stange, a professor of public policy at the University of Michigan, studies the outcomes of differential tuition and has found that higher prices tend to dissuade students. The generally accepted consensus is that a $1,000 change in costs is associated with a 5 percentage point difference in enrollment rates. Similarly, a June study from Hanover Research found that for every $100 increase in tuition, enrollment decreased by 0.5% to 1%.
“When institutions start charging more for engineering and business, we do see a decline in the number of students pursuing those degrees,” Stange said. But he thinks it’s unlikely that lowering tuition will persuade huge numbers of people to major in such rigorous, technical fields. “Getting humanities majors to become engineering majors is probably a stretch.”