The "little voice in your head" can be your worst critic and greatest supporter. It's been known to help with directions, give advice, and even remind you to put potatoes on the grocery list.
But does everyone have an inner monologue? For a long time, it was assumed that an inner voice was simply part of being human. But it turns out, that's not the case—not everyone processes life in words and sentences.
"By inner monologue, we mean that we can have private speech that's addressed to ourselves and that is carried out without any sound," said Helene Loevenbruck, a senior neurolinguistics researcher at CNRS.
With true inner speech, you almost "hear" your inner voice, she told Live Science. You're aware of its tone and intonation (语调). For example, the voice can "sound" angry or worried.
This long-held assumption was first challenged in the late 1990s by Russell Hurlburt, a psychologist at the University of Nevada, Las Vegas. Hurlburt studied participants' inner speech by asking them to wear a beeper. Whenever the device beeped, they had to write down what they were thinking or experiencing in their mind just before the sound.
Perhaps the participant wrote down, "I need to buy some bread." He would then ask if that's what they actually thought. "Or did you think 'bread'? Or were you hungry?" Loevenbruck explained. After several meetings, participants got better at articulating (流利连贯地表达)their true thoughts, she said. Eventually, this method revealed that some people had inner speech every time the device beeped. But others had less inner speech than usual, and some didn't have inner speech at all. They experienced images, sensations and emotions, but not a voice or words.
The lack of an inner monologue has been linked to a condition called aphantasia (心盲症)sometimes called "blindness of the mind's eye." People who experience aphantasia can't mentally picture their bedroom or their mother's face. Many times, those who don't experience visualizations don't experience clear inner speech, either, Loevenbruck noted.
