The hypodermic needle model suggests that media messages directly inject ideas into passive audiences, similar to how a needle injects a substance into the body. It was commonly used in early 20th century war propaganda to spread ideas and influence audiences. While seen as too simplistic today, elements of the hypodermic needle model can still be found in how some media aims to increase future consumption by emphasizing the producer's perspective. The model was demonstrated effectively in the 1938 War of the Worlds radio broadcast, as many people believed the fictional reporting and took action.