1. A method, comprising: presenting at least one characteristic to at least one member of at least one population cohort; measuring at least one physiologic activity of the at least one member of the at least one population cohort, the at least one physiologic activity proximate to the presented at least one characteristic; associating the measured at least one physiologic activity with at least one mental state; storing, in at least one cohort-linked attribute store, at least one association of at least one avatar attribute with the at least one population cohort at least partially based on the at least one characteristic and the at least one mental state; receiving at least one indication of interest in at least one cohort-linked avatar attribute; obtaining at least one cohort-linked avatar attribute from the at least one cohort-linked attribute store responsive to the received at least one indication of interest; and transmitting the obtained at least one cohort-linked avatar attribute.