The hypodermic needle theory from the 1930s and 1940s suggests that mass media can directly influence large groups of people by "injecting" them with powerful messages designed to elicit responses. It implies that the audience is passive and will immediately accept the information from media sources without question. Factors that contributed to this view include the rise of new media like television and radio increasing exposure, as well as the growth of advertising and persuasion industries deliberately manipulating the public. While this theory was influential, it did not account for individual differences in how people interpret messages.