Hovland et al. measured the soldier’s opinions five days or nine weeks after they were shown a movie presentation of army propaganda. It was found that the difference in opinions of those who had observed the army propaganda movie and those who did not watch the movie were greater nine weeks after viewing it than five days. The difference in delayed persuasion is (which Hovland et al. termed) the sleeper effect, where there was a significant increase of persuasion in the experimental group.[9]