1- What is the illusion of truth effect?
The illusory truth effect is a cognitive bias that occurs when we tend to believe that a piece of information is true simply because it has been repeated several times. Even if the information is false, our brain has a natural tendency to accept it as true after repeated exposure. In other words, the more we hear information, the more correct it seems to us, even if it is wrong.
2- The mechanisms of the illusion of truth effect
This bias is based on the principle of cognitive familiarity: information we have already encountered is easier for our brain to process, giving us the illusion that it is reliable. The effect is all the more powerful because we make no conscious effort to verify the information. It can be reinforced by factors such as the simplicity of the message, the authority of the source, or the emotion aroused by the information.
3- A key element of advertising
The illusion of truth bias is a key element of advertising and is used extensively. Advertisers often use the same slogans or phrases repeatedly in their ads to make them more memorable and persuasive. Even if the claims in the ad are false or exaggerated, people may believe them simply because they have heard them over and over again.
4- A powerful propaganda tool
In politics, the illusion of truth bias plays a central role in spreading ideas and shaping beliefs. Election campaigns, in particular, are often the breeding ground for unrealistic promises or false claims, which, through constant repetition, end up being perceived as true by part of the electorate.
This strategy is based in particular on the sophism argumentum ad nauseam, a rhetorical technique that consists of repeating an argument until it is accepted as obvious, even in the absence of tangible evidence. Thus, simplistic speeches, powerful slogans, or misrepresented figures can shape public opinion, influencing election results and democratic debate.
>>> see also: Fallacious arguments
Furthermore, propaganda strategies rely on this cognitive bias to manipulate public opinion. History is full of examples where political regimes have used the repetition of simplistic messages to shape the perception of the masses.
>>> See also: Propaganda in wartime: When information becomes a weapon
5- Fake news spreads six times faster than real news.
The digital age has amplified the illusion of truth, particularly through the widespread dissemination of fake news on the internet and social media. A study by MIT has shown that fake news spreads six times faster than verified information and is 70% more likely to be shared. This virality, reinforced by bots that continuously relay this misleading content, exposes us to misinformation on a daily basis. Malicious actors exploit these mechanisms for manipulative purposes: disinformation campaigns, conspiracy theories, polarization of opinion, etc. By regularly exposing internet users to the same misleading narratives, they succeed in instilling doubt and distorting perceptions of reality.
6- How can we protect ourselves from the illusion of truth?
This bias is particularly insidious because it relies on our automatic thinking system, making it difficult to recognize its influence. However, it is possible to guard against it by adopting a critical approach to the information we encounter.
One of the most effective strategies is to check the facts as soon as we are first exposed to a statement. Studies show that people who actively evaluate the veracity of information rather than its interest are less vulnerable to this bias, provided they already have knowledge on the subject. Developing the reflex to question information rather than consuming it passively therefore reduces its impact.
In practice, this means:
Check the source: a recognized media outlet or scientific study is more reliable than an anonymous post on social media.
Cross-check the information: a claim relayed only by dubious or sensationalist websites should arouse suspicion.
Be wary of emotional content: misinformation often plays on outrage, fear, or excessive enthusiasm to spread more effectively.
The illusion of truth is a powerful cognitive bias that explains why we tend to believe that what we hear repeated is true. This illusion of truth can fuel the spread of fake news and conspiracy theories, especially in a digital environment where information is constantly repeated. By adopting a critical attitude and checking the facts, we can reduce the influence of this bias on our decisions and our perception of the world.
