When I was about 14 I came across a book called "Subliminal Seduction" by Professor Wilson Brian Key. If you click on the link you can read a copy of the book. The forward was written by Marshall McLuhan the father of studying media in many ways. McLuhan was the one who coined the phrase, "the media is the message". As a result of reading the book I began investigating psychological manipulation on the public and individuals. Later I learned hypnosis and studied brain washing too. In college I declared a degree in Political Science; but, qualified for degrees in Psychology and Sociology. I even studied under Jack Levin, one of the fathers of the profiling of serial killers.
Two events that really demonstrated, for me, how effective psychological manipulation included the Patty Hearst kidnapping and the the mass kidnapping that led to what is known as the "stockholm syndrome". During my late teens there was also a rise in cults which used psychological techniques to control the minds of its followers. Certainly we are all aware of the propaganda used by Germany during World War II. In fact they learned it from Edward Bernays who wrote the book "Propaganda" and was the nephew of Sigmund Freud. Mr. Bernays took Freuds psychological concepts and turned them into tools for governments and corporations to use them on the public to get them to accept beliefs they might not otherwise. In order to get women to smoke he came up with the idea of convincing women that if men could smoke, they could to, that smoking was a sign of female freedom, he left out the cancer part.
During the 1950s up to and possibly beyond, the United States government began experiments in mind control known generically as MKUltra, based on experiments done by the Nazis and the Japanese during World War II and our own home grown experiments. The little we know, as the CIA ordered the destruction of most of the data obtained in over 150 different programs, came from a congressional committee investigation by the "Church Committee". We discovered that the United States had secretly given LSD to salesmen when they visited prostitutes to see its effects and even fed mentally challenged kids in Canada radioactive cereal to see the effect on them. We also found out that the CIA paid news reporters to file articles to propagandize both Americans and foreign governments.
One form of psychological pressure combined with physical "torture" is called by the United States government, "Enhanced interrogation techniques". The most famous technique our government continues to use is called "waterboarding" but, the reality is the most effective is a form of sleep deprivation.
Most people want to believe they cannot be manipulated. The fact is just about anyone if not everyone can and in fact with little effort. Once manipulated the hardest thing is to recognize that fact because you feel stupid, it is not stupidity, it is simply how our minds work. One of my favorite magicians is Penn Jillette, of Penn and Teller, he has often said that magicians are professional liars. Psychics are another example of professional liars, they just try to tell you they are not tricking you, sort of like the media and the government do.
The New York Times - To fight vaccine lies, authorities recruit an "Influencer Army". I came across this article after making my post. Just an example of how the government still pays people to influence (propagandize) without the influencers telling you they are being paid to do so.