This study uses theories of cognitive processing to analyze the failure of employer and union campaigning to change employee predispositions to vote for or against union representation. Consistency theory does not wholly account for the results because there was no general pattern of selective exposure. The pattern of exposure was also not that hypothesized by complexity or satiation theories. It is argued that insulation from the effect of persuasive communications is a complex cognitive process that can control either exposure to or assimilation of the communications.