Bandwagon
hi ho hi ho its off to work we goThe bandwagon technique is used to persuade people of something by implying that everyone else is doing it as well. This technique works well because few people want to be left behind. This advertisement persuades people to enlist to the army to “help win the war” by showing so many other people who are enlisting and going “off to work” as well. The phrase “squeeze in one more” implies that there are already many people in the ‘bandwagon’ who are working to help the war. Not only does this justify the audience enlisting, but it also helps them feel like they’re part of the flow. Also, the chant of the people on the bandwagon that goes: "Hi ho! Hi ho! It's off to work we go!" is similar to that of the seven dwarves in the fairy tale Snow White and the Seven Dwarves. Because it is the chant of the seven dwarves, who act in unity and work together in everything, the advertisement suggests that everyone is working together to fight the war, strengthening the sense of unity and the necessity of everyone joining the army.
http://www.freevintageposters.com/2014/01/help-win-war-squeeze-in-one-more.html