Sky-high TV ratings and well-honed messages give presidential debates a distinct air of egalitarianism. But if 2008 is any guide, Wednesday's debate between President Obama and Mitt Romney is much more likely to attract Joe Seven-Figures salary than Joe Six-Pack. 

Voters with the highest incomes and college degrees were the most likely to watch the first debate in 2008 between Obama and Sen. John McCain (D-Ariz.), according to a Pew Research Center survey.

Source: Pew Research Center poll Sept. 27-29, 2008. Graphic: Scott Clement

Roughly three-quarters of voters with post-graduate degrees and with annual incomes of at least $100,000 said they watched at least "a little" of the debate, compared with about half of voters in the lowest income and education groups.

The big income and education gap may repeat itself this year. A Washington Post-ABC News poll this week found higher income and education voters were more likely than others to say they were "very interested" in the presidential debates. 

In addition to debate watching, higher income and education voters have a history of heightened political interest and typically turn out at higher rates on Election Day.