Only in recent years have scientists found that not everyone has the sense of an inner voice – and a new study sheds some light on how living without an internal monologue affects how language is processed in the brain.
This latest study, from researchers at the University of Copenhagen in Denmark and the University of Wisconsin-Madison in the US, also proposes a new name for the condition of not having any inner speech: anendophasia.
This is similar to (if not the same as) anauralia, a term researchers coined in 2021 for people who don’t have an inner voice, nor can they imagine sounds, like a musical tune or siren.
Focusing on inner voices in this study, the team recruited 93 volunteers, half of whom said they had low levels of inner speech, while the other half reported having a very chatty internal monologue. These participants attempted a series of tasks – including one where they had to remember the order of words in a sequence, and another where rhyming words had to be paired together.
“It is a task that will be difficult for everyone, but our hypothesis was that it might be even more difficult if you did not have an inner voice because you have to repeat the words to yourself inside your head in order to remember them,” says linguist Johanne Nedergård, from the University of Copenhagen.
“And this hypothesis turned out to be true.”
The volunteers who reported hearing inner voices during everyday life did significantly better at the tasks than those without inner monologues: Inner speakers recalled more words correctly, and matched rhyming words faster. The researchers think this could be evidence that inner voices help people process words.
It’s interesting to note that the performance differences disappeared when the volunteers spoke out loud to try and solve the problems they were given. It may be that using an audible voice is just as effective as using an inner voice in these situations.
In two other tasks, covering multitasking and distinguishing between different picture shapes, there was no difference in performance. The researchers take this as a sign that the way inner speech affects behavior depends on what we’re doing.
“Maybe people who don’t have an inner voice have just learned to use other strategies,” says Nedergård. “For example, some said that they tapped with their index finger when performing one type of task and with their middle finger when it was another type of task.”
The researchers are keen to emphasize that the differences they found would not cause delays that you would notice in regular conversation. We’re still at the very early stages in terms of figuring out how anendophasia might affect someone – and likewise anauralia.
Early findings from research at the University of Auckland suggest people with a ‘silent mind’ remember verbal information in similar ways to those who experience typical auditory imagery.
But there may be differences we don’t yet know about. One area the team thinks is worthy of further investigation is ‘talking therapy’ practices, such as cognitive behavioral therapy, which involves trying to change thought patterns. It may be that having an inner voice makes that easier for some people to achieve than others.
“The experiments in which we found differences between the groups were about sound and being able to hear the words for themselves,” says Nedergård.
“I would like to study whether it is because they just do not experience the sound aspect of language, or whether they do not think at all in a linguistic format like most other people.”
The research has been published in Psychological Science.
