1. A system comprising: circuitry for presenting to at least one member of a population a plurality of avatars associated with at least one instance of media content; circuitry for measuring at least one physiologic activity of the at least one member of the population, the at least one physiologic activity proximate to at least one presented avatar among the plurality of avatars associated with at least one instance of media content; circuitry for associating the at least one physiologic activity with at least one mental state, including circuitry for identifying at least one preferred instance of media content based on the at least one mental state; and circuitry for identifying at least one instance of media content based on the at least one mental state.