Cain then went on to say he thought liberals were upset with him "because I won't stay on the Democrat plantation like I'm supposed to."
"It may shock you but some black people can think for themselves," he added.
Cain was one of several presumed GOP presidential candidates who spoke at the Conservative Principles Conference on Saturday, an event organized by Iowa Rep. Steve King (R). Mississippi Gov. Haley Barbour (R), Newt Gingrich, and Rep. Michele Bachmann (R-MN) also spoke at the event.
Cain won the event's straw poll with 42 out of the 127 votes to beat out Gingrich (13), Bachmann (12), and Barbour (2.) Last month, Cain won a straw poll at a Tea Party summit in Arizona.