How we change what others think, feel, believe and do
Make it appear that many people have joined the cause already, and that they are having lots of fun or getting significant advantage.
Show that those who join early will get the better prizes, such as positions of authority or other advantages.
Link it to morality and values, showing that those who join sooner are more moral and pretty much better people all around.
Make a loud noise. Use bright colors. Play a fanfare. Become impossible to miss. Be in-your-face until they join up.
A political party holds a rally with much flag-waving and razz-a-ma-tazz.
A new religious group ensures all of its members attend services and become active participants in recruiting new members.
The Bandwagon uses social evidence to legitimize itself and become attractive. It plays heavily on the need for belonging, making the group a desirable place to be. It may also use the scarcity principle, showing that it is better to join sooner or later.
The term 'bandwagon' came from the Temperance movement, where an open wagon would literally have a band on it and drive around town picking up drunks who would symbolically 'get on the wagon' of alcohol-free (and religious) living.
Clyde Miller, Propaganda Analysis, NY: Institute for Propaganda Analysis, 1937