Conversations in Our Heads

It might not be surprising that writers often give superheroes, aliens, and magical beings the power of telepathy. Just imagine what you could learn about someone if you could hear their thoughts. But here’s a twist: not everyone has an internal monologue—or what psychologists call inner speech. Even those who do don’t always have constant internal dialogues. Understanding inner speech can reveal a lot about how our brains function, develop, and communicate, but research is still in its early stages.

Inner speech is generally defined as the process of “speaking” meaningful thoughts without vocalizing or moving any part of the body. It’s different from visualizing or sensing things, and it involves specific words with the same tone and inflection as if spoken aloud—though this isn’t always the case. Studying inner speech has been challenging because it’s difficult to measure people’s internal experiences. This has led to varied research methods and inconsistent findings.

Some studies have investigated inner speech by prompting participants with specific words or phrases, such as asking them to read silently or determine if words rhyme mentally. These studies have uncovered interesting patterns, like how people tend to mentally process single words rather than every word of a sentence when reading. However, prompted inner speech differs from spontaneous inner speech, and these prompts don’t provide a full picture of how often or why people use inner speech in daily life.

To address these gaps, researchers use questionnaires to explore inner speech. Findings suggest that inner speech often revolves around self-criticism and negative emotions, usually expressed in full sentences. Only about one-third of people report using abbreviated inner speech, where a single word or phrase represents a complex thought. Questionnaires may overestimate the frequency of inner speech because people are often unaware of their internal experiences.

Recently, a method called Descriptive Experience Sampling (DES) has been used, where participants carry a beeper that prompts them to record their thoughts when it goes off. This approach offers a better sense of how often people experience inner speech and reveals that inner monologues exist on a spectrum. About 70-85% of people experience some form of spontaneous inner speech occasionally, with most engaging in it about 15-30% of the time.

Inner speech can also involve multiple experiences simultaneously, such as visualizing while talking to oneself. Additionally, many people experience dialogic inner speech, where they have conversations with themselves, often playing both roles. Those who had imaginary friends as children are more likely to use this dialogic form of inner speech. Others might engage in imagined interactions, where they rehearse conversations or scenarios in their heads.

Despite these insights, the origins of inner speech remain unclear. Evolutionary theories suggest it evolved as a byproduct of spoken language, with internal speech helping to detect errors in speech. However, inner speech and overt speech are not always linked—some individuals may lose one without losing the other. It’s also possible that inner speech evolved for other cognitive purposes.

Some psychologists believe that our inner speech reflects past conversations with caregivers, which get internalized and replayed as we grow. This might explain why inner speech often resembles a conversation and is focused on self-regulation, problem-solving, and planning.

Research indicates that inner speech plays a crucial role in cognition, such as problem-solving and working memory. For instance, people who use inner speech to talk through problems tend to perform better on cognitive tasks. Inner speech also appears to influence mental health, with connections to conditions like depression, anxiety, and even psychotic disorders.

Researchers are keen to understand more about inner speech, including its origins, variations, and implications. There are many unanswered questions, such as whether you can change your inner monologue or if different types of inner speech have benefits or downsides. Until we have clearer answers, discussing inner speech and its effects can still be fascinating.