Psychologists call it ‘the illusion of truth’ and politicians and advertisers know all about it.
Simple repetition is one of the best methods of persuasion, many studies have found.
People are more likely to believe a statement is true if they hear it twice than if they hear it once — regardless of whether it is true or not.
Psychologists call it ‘the illusion of truth‘ and politicians and advertisers know all about it.
Dr Lisa K. Fazio, the study’s first author, said:
“When we rely on our initial gut feelings to determine truth, we often use unreliable cues such as repetition.
It’s important to instead slow down and think about how we know a statement is true or false.
This is especially important on social media where news feeds have been designed to encourage quick reads and quick responses.”
Now a study looks at the age at which this illusion emerges.
The study included both 5- and 10-year olds, along with some adults, who all listened to both true and false statements, some of which were repeated.
Here are some of the statements given only to children:
- “Tomatoes grow above ground” (True)
- “Potatoes grow above ground” (False)
Dr Fazio explained:
“We were specifically interested in whether young children would use repetition as a cue for truth.
Five-year-olds are old enough to understand the concept of truth, but they are not very good at reflecting on their own thinking.
Ten-year-olds are much more skilled than 5-year-olds at reflecting on their thinking, but not as good as adults.
As a result, if learning to use repetition as a cue for truth requires this reflection, you would not expect to see an illusory-truth effect in 5-year-olds or maybe even the 10-year-olds.”
The results showed that both age-groups of children, along with adults, displayed the illusory truth effect.
In other words, children and adults think statements are more true if they are repeated.
Prior knowledge did not protect any age-groups from the illusory truth effect.
Dr Fazio said:
“Our results suggest that children learn the connection between repetition and truth at a young age.
In general, statements that you hear multiple times are more likely to be true than something you are hearing for the first time.
Even by the age of 5, children are using that knowledge to use repetition as a cue when making truth judgments.
This is useful most of the time, but it can cause problems when the repeated statements are false.”
The study was published in the journal Psychological Science (Fazio et al., 2020).
