Do You Have No Inner Voice? 1 in 10 Don't and It's a Problem

Do you have an inner voice? As many as 1 in 10 people don't, and this could be affecting their ability to remember words.

In the past, it was commonly assumed that inner speech was a universal human experience. However, in recent years, scientists have found that not everyone has this running internal monologue, with between 5 and 10 percent of people lacking an inner voice.

"Some say that they think in pictures and then translate the pictures into words when they need to say something," linguist Johanne Nedergård from the University of Copenhagen said in a statement.

"Others describe their brain as a well-functioning computer that just does not process thoughts verbally, and that the connection to loudspeaker and microphone is different from other people's. And those who say that there is something verbal going on inside their heads will typically describe it as words without sound."

In a new study published in the journal Psychological Science, Nedergård and colleague Gary Lupyan from the University of Wisconsin-Madison decided to investigate whether this lack of inner voice—which the duo have named anendophasia—could affect how people solve problems and retain information.

The study involved 93 adults, half of whom reported low levels of inner speech. The participants were given four tasks to complete, which included remembering words in a sequence and determining whether a set of pictures contained words that rhyme.

For the first task, the team hypothesized that those with anendophasia would find it harder to remember these long lists of words, as it helps to repeat them to yourself in your head.

"And this hypothesis turned out to be true," Nedergård said. "The participants without an inner voice were significantly worse at remembering the words. The same applied to an assignment in which the participants had to determine whether a pair of pictures contained words that rhyme, e.g. pictures of a sock and a clock. Here, too, it is crucial to be able to repeat the words in order to compare their sounds and thus determine whether they rhyme."

But besides struggling to play certain word games, does anendophasia hold any practical or behavioral significance for those who experience it?

"The short answer is that we just don't know because we have only just begun to study it," Nedergård said. "But there is one field where we suspect that having an inner voice plays a role, and that is therapy; in the widely used cognitive behavioural therapy, for example, you need to identify and change adverse thought patterns, and having an inner voice may be very important in such a process.

"However, it is still uncertain whether differences in the experience of an inner voice are related to how people respond to different types of therapy."

Nedergård added that more work needs to be done to fully understand the implications of anendophasia.

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