Many people have moments when they talk to themselves, and this inner voice speaking to them can play an important role in verbal memory.
A new study found that between 5% and 10% of the population do not have an inner voice, and therefore they find it difficult to perform certain memory tests.
Previously, it was commonly believed that having an inner voice was a common human thing. But in recent years, researchers have come to realize that not everyone shares this experience.
According to postdoctoral researcher and linguist Johan Nedergaard from the University of Copenhagen, those who live without an inner voice take a long time and have difficulty translating their thoughts into words.
Johan and Gary Lupyan of the University of Wisconsin-Madison coined the term anendophasia to describe the absence of conversations that occur in most people's minds.
Johan Nedergaard and her colleague Gary are the first researchers in the world to investigate whether the lack of an inner voice, or anendophasia, has any consequences for how these people solve problems. For example how to perform verbal memory tasks.
During the study, about 100 participants, half of whom had a very little inner voice and the other half had a high degree of inner voice in their daily lives, were assigned to conduct four experiments.
In the first phase, participants had to remember words that were phonetically or orthographically similar in order, such as “bought,” “caught,” “tight,” and “wart” (fisheye).
“It's a task that's going to be difficult for everyone, but our hypothesis is that it's almost more difficult if you don't have an internal voice because you have to repeat the words to yourself inside your head in order to remember them,” Johan said.
She continued: “This hypothesis turned out to be correct. Participants who did not have an inner voice were significantly worse at remembering words.”
In the second test, participants had to determine whether a pair of pictures contained rhyming words.
“Here too, it is very important to be able to repeat words to compare their sounds and thus determine whether they rhyme or not,” Johan points out.
In two other experiments, in which the researchers tested the role of the inner voice in quickly switching between different tasks and distinguishing between very similar shapes, they did not find any differences between the two groups. Although previous studies suggest that language and inner voice play a role in this type of experience.
However, the researchers did not notice differences in the two groups when they were tasked with quickly switching between different tasks and distinguishing between very similar characters. This was surprising because previous research suggested that language and inner speech play a role in these types of tests.
According to Johan, “People who do not have an inner voice may have just learned to use other strategies.”
According to Johan, the differences in verbal memory they identified in their experiments would not be observed in normal everyday conversations. The question is: Does having an inner voice have any practical or behavioral significance?
She explained: “The short answer is that we don’t know because we are just starting to study it. But there is one area where we suspect that the presence of an inner voice plays a role, and that is therapy, the widely used cognitive behavioral therapy.”
“However, it is still uncertain whether differences in the experience of the inner voice are related to how people respond to different types of therapy,” she added.
The results of the experiments were published in the journal Psychological Science.