Editing Vested interest (communication theory) (section)

===Comprehensive exam experiment===
In a second study, Sivacek and Crano<ref name="S&C"/> visited [[Michigan State University]]. In this experiment, subjects were informed that the university was considering the addition of a senior comprehensive examination to the graduate prerequisites. Respondents were given the following options:
#Do nothing
#Sign an opposing petition
#Join a group that opposed the referendum
#Volunteer specific numbers of hours to the opposing group's activities
The respondents were grouped into the same three categories as the drinking age study: high, moderate, and low vested interest. The study found that those with the highest levels of vested interest were significantly more inclined to take action based on their attitudes concerning the issue; that is, their resultant behaviors (signing the petition, joining the group, pledging multiple hours with the group) occurred much more consistently and prevalently than that of the other two vested interest groups.<ref name="S&C"/>