The 'Hypodermic Needle Theory' is referred to by many different names, including the 'Hypodermic-Syringe Model, 'Transmission-Belt Model', or even the 'Magic Bullet Theory'. When talking about this theory, these names are often easily interchanged with one another.

The origins of the theory itself can be dated back to the 1930s, however not long after, it lost its prominence as people began to view it as obsolete. Due to big data analytics-based and mass customization, a modern revival of the basic idea proposed by the theory has become increasingly accepted once again.

The 'Hypodermic Needle Theory' is a communication model, which suggests that an intended message is directly received and wholly accepted by the receiver. The basic concept of the theory is that the mass media is a powerful tool as it can influence a very large group of people directly and uniformly by ‘shooting’ or ‘injecting’ them with appropriate messages designed to trigger the desired response. This helps to explain why the theory has gained names for itself, such as the 'Magic Bullet', which graphically assumes that the media's message is a bullet fired from the media gun into the viewer's head. Similarly, the 'Hypodermic Needle Model' uses the same idea by proposing the thought that the media injects its messages straight into the attention of passive audience members. The theory expresses the view that the media is a dangerous means of communicating because the receiver or audience is powerless to resist the impact of the message. There is no escape from the effect of the message in this model. The audience must think in a conforming manner, as they are provided with no other source of information or an alternative view.

Overall, I believe that the 'Hypodermic Needle Theory' and the 'Two-Step Flow Theory' both have their clear advantages, but also downfalls. In terms of the 'Hypodermic Needle Theory', I believe that it contains certain elements of truth within its basic concept, as to some extent I do believe that audience members are subject to believing the information which they consume. With the rise of technology, greater access to a wider range of information, and the downfall of the previously dominant gatekeepers, I also note, that it would be naive to believe that this theory is still wholly relevant to apply to the audience in the modern-day conditions in which we live. When analyzing the 'Two-Step Flow Theory', I do believe in my opinion that it is more relevant to the audience in modern days. I can understand the position of many opinion leaders in society and agree with the influence which they have over large proportions of the media, however, I do also recognize there are some individuals which will not comply with the opinion leader's perception of a media text, because they will instead create their own interpretations and meanings, some of which could clash with the dominant ideology.

A prime example of the 'Hypodermic Needle Theory' in practice can be noted via the 'War of the Worlds' broadcast, which took place in America on October 30th, 1938. On the eve of Halloween, radio programming was interrupted with a news bulletin whereby the audience was informed that Martians had begun an invasion of Earth in a place called Grover's Mill, New Jersey. The result of this was to cause widespread panic amongst the American mass audience listeners, with it being believed by 1 million people. Consequently, a wave of mass hysteria disrupted households, interrupted religious services, caused traffic jams and clogged communication systems. People fled their city homes to seek shelter in more rural areas, raided grocery stores, and began to ration food. The nation was in a state of chaos, and this broadcast was the cause of it. It became known as the 'Panic Broadcast'. This demonstrates exactly how the theory worked, by injecting the message directly into the bloodstream of the public. The effects of the broadcast suggested that the media could manipulate a passive public, leading theorists to believe this was one of the primary ways media authors shaped audience perception.

As with any proposed theory, there is some opposition, which dwells upon the disadvantageous and downfalls. For the 'Hypodermic Needle Theory', individuals have stated that this theory's ideas are too simplistic as they don't take into consideration the changing attitudes and beliefs of people. As 'Stuart Hall' outlined in his 'Reception Theory', audience members will consume media texts in different ways. Furthermore, external factors, such as social or demographic changes can alter audience preferences. Moreover, many believe that the theory is outdated and not relevant to apply to today's society. In the current day, audience members are much more likely to have a better understanding of the media and awareness of how messages are constructed within it. This increased knowledge, and in some instances more sophisticated audience base, subsequently means that the audience will not always revert to the same thinking pattern every time. Instead, they may create their own interpretations and views, some of which may even clash with the dominant ideology being portrayed in the media text in question.

Following the 'Panic Broadcast' and the abundance of criticism which was circulating about the theory, both as previously mentioned, a research movement was conducted by which individuals are known as 'Paul Lazarsfeld' and 'Herta Herzog' would assess the validity of the theory itself. This movement would later disprove the basic idea and concept of the 'Hypodermic Needle Theory, when 'Hadley Cantril' managed to show that reactions to the broadcast were, in fact, diverse, and were largely determined by situational and attitudes of the listeners. 'Lazarsfeld's' debunking of the 'Hypodermic Needle Theory' of communication provided the way for new ideas regarding the media's effects on the public. Lazarsfeld thereby introduced his idea of the 'Two-Step Flow Theory' of communication.

As previously mentioned, the 'Two-Step Flow Theory', was originated by 'Paul Lazarsfeld' when he disproved the ideas of the 'Hypodermic Needle Theory'. Another individual named 'Elihu Katz further contributed to the theory in 1955. The model of the 'Two-Step Flow' of communication assumes that ideas flow from the mass media by following a chain. First to the opinion leaders and then to the greater public. 'Lazarsfeld' believes that messages of the media are transferred to the masses via opinion leadership (a style of leadership where certain individuals who are active media users, interpret the meaning of media messages or content for lower-end media users). This theory emphasizes that these leaders essentially consume the media's information, and then explain it by spreading the messages to others. It is believed that this is necessary because the media does not directly have an influence on viewers anymore, as instead, selective exposure plays a larger role in influencing the public in the modern age.

At present day, big data analytics have identified user preferences and messages to individuals as an example suggesting the renewal of the idea of a one-step flow of communication. This in principle is like the 1930's 'Hypodermic Needle Theory'. Evidence to support this thinking is the fact that recent studies have found that traditional mass media outlets receive 80–90% of their 'Twitter' mentions through a direct one-step flow from average 'Twitter' users. A modern revival of the basic ideas proposed by the 1930's theory is becoming increasingly apparent, meaning they have become more accepted to some extent once again.