Inner monologues are still a mystery

Summary

Podcast Summary: Short Wave — “Inner Monologues are Still a Mystery”
Date: June 8, 2026
Hosts: Emily Kwong & Rachel Carlson
Guest Experts: Russell Hurlburt (psychologist, University of Nevada), Charles Fernyhough (professor of psychology, Durham University)

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Episode Overview

In this episode, hosts Emily Kwong and Rachel Carlson explore the fascinating world of inner speech—or the lack thereof. Prompted by audience curiosity, they dig into why some people have a constant internal monologue while others think in images, emotions, or silence. They discuss how scientists study these “inner experiences,” the brain regions involved, and the complexity of interpreting what goes on inside our minds. Special guests Russell Hurlburt and Charles Fernyhough share their pioneering research and insights, celebrating the diversity of human thought.

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Key Discussion Points & Insights

1. Not Everyone Has an Inner Monologue

• Emily Kwong reveals she does not have a word-based inner monologue; instead, her “inner experience” is a landscape of images and emotions.
  • “My inner experience isn’t really word based. It’s more like a moving landscape of images. It’s kind of like soaking in an emotional bath.” (Emily Kwong, 01:13)
• Rachel Carlson has a constant, dialogue-heavy monologue—“like a screenplay.”
  • “Mine is loud. Oh, no, it does not feel like a bath...it feels like it’s dialogue heavy.” (Rachel Carlson, 01:32)
• Listener reactions included skepticism and curiosity, prompting the team to consult scientific literature and experts.

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2. Studying Inner Experience

• Russell Hurlburt's Method:
  • Early attempts used questionnaires, but responses were unreliable:
    • “People didn’t know what they were talking about when they picked a number on a Likert scale...The data was just rotten on the way in.” (Russell Hurlburt, 02:33)
  • Developed Descriptive Experience Sampling (DES): participants reported their inner thoughts in real time when prompted by a beeper, then discussed entries with researchers.
  • Acknowledges the imperfections:
    • “You’ve got no good reason to be confident that you do or do not have an inner monologue because there’s just too many layers between what your inner experience actually is and what you might say about it.” (Russell Hurlburt, 03:16)

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3. The Science of Studying Inner Speech

• Charles Fernyhough explains the developmental origins:
  • Private speech (children talking aloud to themselves) precedes inner speech; both originate from social dialogue and gradually become internalized.
    • “When kids are talking to themselves out loud, we call that private speech...that private speech came from the social dialogues that kid enjoyed when they were growing up.” (Charles Fernyhough, 06:18)
  • Draws on theories from Russian psychologist Lev Vygotsky.
• Brain Regions Involved:
  • Language systems in the left hemisphere—Broca’s area (producing complex speech/actions) and Wernicke’s area (processing language)—are activated during inner speech.
  • Inner dialogue involves brain regions beyond just those for language, including those used for representing other people’s minds.
    • “You also get another region way on the other side of the brain...representing yourself as a partner in that conversation.” (Charles Fernyhough, 08:59)

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4. Scanning the Brain: Elicited vs. Spontaneous Inner Speech

• Fernyhough & Hurlburt’s Study:
  • Participants practiced DES, then were scanned in an fMRI while experiencing inner speech.
  • Key finding: Elicited (instructed) inner speech and spontaneous (natural) inner speech activate the brain differently.
    • “When we had elicited inner speech, there was lots of that Broca’s area...But when people were doing inner speech spontaneously, there was much less of that.” (Charles Fernyhough, 10:46)
  • Warns neuroscientists about assuming lab tasks accurately reflect real mental experience.
    • “We shouldn’t assume that when you put somebody in the scanner and tell them to do something, the thing that results is anything like the thing you’re actually interested in.” (Charles Fernyhough, 11:19)
  • Emily likens studying spontaneous inner speech to birdwatching: “The bird is your own brain.” (Rachel Carlson, 11:40)

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5. Voice Hearing and Its Connection to Inner Speech

• Voice Hearing:
  • Defined as hearing a voice that isn’t produced by an external source; associated both with mental illness and with people who find voices creative or spiritual.
  • Many people who hear voices are not distressed or do not seek psychiatric help.
  • Leading theory: Some instances involve inner speech misattributed by the brain as coming from an external source due to disruptions in communication between Broca’s and Wernicke’s areas.
    • “When, usually when you’re speaking, that bit at the front sends a little internal message...don’t pay too much attention to it...In the case of voice hearing, that message doesn’t get through in the same way.” (Charles Fernyhough, 13:25)

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6. Mental Diversity and Inner Speech

• Many people do not use inner speech much, or at all, relying instead on images, music, emotions, or other forms of thought.
• Charles celebrates cognitive diversity and cautions against pathologizing silence or promoting inner speech as superior.
  • “I think it’s wonderful that there is this diversity and we...can celebrate that diversity. I wouldn’t ever want to set out and say to people that they should improve their inner speech...” (Charles Fernyhough, 14:32)
  • If inner speech is distressing (“excessively critical”), there are ways to rethink and address it.
  • For information and support regarding voice hearing, visit understandingvoices.com.

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Notable Quotes & Memorable Moments

• On the uncertainty of self-knowledge:
  • “You’ve got no good reason to be confident that you do or do not have an inner monologue...there’s just too many layers between what your inner experience actually is and what you might say about it.” (Russell Hurlburt, 03:16)
• On cognitive diversity:
  • “I’d like to celebrate the diversity of human minds. I think we are so different.” (Charles Fernyhough, 14:27)
• On the challenges of neuroscience research:
  • “We shouldn’t assume...the thing that results [in the scanner] is anything like the thing you’re actually interested in. So, neuroscientists, beware.” (Charles Fernyhough, 11:19)
• Humorous analogy:
  • “That inner speech, like spontaneous inner speech, sounds like birding. You scientists have to patiently wait and see if a bird shows up, but the bird is your own brain.” (Emily Kwong and Rachel Carlson, 11:31-11:42)

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Timestamps for Important Segments

• 00:41 — Emily reveals she has no inner monologue
• 01:13–01:52 — Jobs compare experiential differences (images vs. words)
• 02:01–03:52 — Hurlburt explains methods for studying inner experience
• 05:56 — Introduction of guest Charles Fernyhough
• 06:11–07:33 — Fernyhough on how inner speech develops from childhood social dialogue
• 07:37–09:25 — Brain mechanisms and dialogic nature of inner speech
• 09:48–11:31 — fMRI studies: differences between elicited and spontaneous inner speech
• 11:45–13:44 — Voice hearing: definitions, mechanisms, relation to inner speech
• 13:50–15:26 — Celebrating diversity in inner mental experiences; mental health considerations

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Tone & Style

• The conversation is casual, engaging, science-forward, and peppered with humor (“Me, myself and my voice,” “la la la la,” etc.).
• The hosts foster curiosity, humility, and an appreciation for the diversity of experience without oversimplifying neuroscience.
• Experts are respected and their research is carefully explained for a general audience.

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Further Resources

• For more on voice hearing and support: understandingvoices.com

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This episode is a concise yet rich primer on the science (and mystery) of our inner worlds—whether they’re filled with voices, silent images, or something else entirely.

Transcript

[Commercial Announcer]

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[Emily Kwong]

You're listening to Short Wave from NPR. Hey, short waivers.

[Rachel Carlson]

It's Emily Kwong and Rachel Carlson, shortwave producer. And Emily, I think it's pretty safe to say that both of us read the team inbox shortwavenpr.org, every morning.

[Emily Kwong]

Fervently.

[Rachel Carlson]

Exactly. And two months ago, you said something to reporter John Hamilton that really piqued our audience's interest.

[Emily Kwong]

I don't have an inner monologue.

[Charles Fernyhough]

Not everybody has an inner monologue. This is, this is something that doesn't work for everybody.

[Rachel Carlson]

I'm safe.

[Charles Fernyhough]

Yeah, exactly.

[Emily Kwong]

But if I'm so proud of myself.

[Rachel Carlson]

And our inbox lit up about this. People wrote, is that even a thing? I don't understand. How is that possible? So we had to confirm. Science backs this up, right? Not everyone has an inner monologue.

[Emily Kwong]

It is true. Scientists confirm for some people, inner speech is far less wordy. So my inner experience isn't really word based. It's more like a moving landscape of images. It's kind of like soaking in an emotional bath. And like feelings.

[Rachel Carlson]

I love it.

[Emily Kwong]

Yeah. And feelings and images will rise and they'll fall, but there's no words. It's real silent.

[Rachel Carlson]

Mine is loud. Oh, no, it does not feel like a bath. It feels like it's dialogue heavy. So whether it's a conversation that I'm having with myself or an imagined conversation with other people. Uh, yeah, it's a screenplay.

[Emily Kwong]

Me, myself and my voice.

[Rachel Carlson]

Yeah, totally.

[Emily Kwong]

La la la la.

[Rachel Carlson]

But Emily, this got us thinking about how different the insides of people's heads are. And it turns out there are scientists who study what's going on in people's minds.

[Russell Hurlburt]

I think it's the most interesting question on the planet. The earliest known writings, like Gilgamesh or whatever you call the earliest writings, are interested in inner experience.

[Emily Kwong]

This is Russell Hurlburt, a psychologist at the University of Nevada. And Russ is, is a legend in the field for being one of the first to gather data on inner experiences through a beeper.

[Rachel Carlson]

Participants carried this device around and every time it beeped, they filled out a questionnaire to quantify their inner experience. But there was a problem.

[Russell Hurlburt]

People didn't know what they were talking about when they picked a number on a Likert scale. And I didn't know what they were talking about. The data was just rotten on the way in.

[Emily Kwong]

So he ditched the questionnaires and instead told participants, every time the beeper goes off roll, write down what's going on internally in your own words.

[Russell Hurlburt]

And then we get together and talk about it.

[Emily Kwong]

Russ called this technique descriptive experience sampling. It was illuminating, sometimes even life changing for the participants involved. But Russ is the first to say how highly imperfect his method is.

[Rachel Carlson]

It's just people saying what's going on in their heads. But how do you confirm?

[Emily Kwong]

Yeah, like, how do you check for accuracy? Like he believes that people do not fully know the characteristics of their inner experience, including me.

[Russell Hurlburt]

You've got no good reason to be confident that you do or do not have an inner monologue because there's just too many layers between what your inner experience actually is and what you might say about it.

[Emily Kwong]

That was humbling to hear.

[Rachel Carlson]

It's humbling, yes. But Emily, you know, even if people can't fully know themselves, scientists are still trying to figure it out, including a collaborator of Russell's, Charles Fernyhough.

[Charles Fernyhough]

We've shown you can do it. Not just us. Teams all around the world have shown that you can study this stuff. You can have a science of it.

[Emily Kwong]

So today on the show, how far can the science go in the quest to know thyself? I'm Emily Kwong.

[Rachel Carlson]

And I'm Rachel Carlson. You're listening to Short Wave, the science podcast from npr.

[Russell Hurlburt]

Foreign

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[Emily Kwong]

Rachel and I are here with Charles Fernihoe. He's a professor of psychology at Durham University and studies inner speech, which is one of many kinds of internal experiences.

[Rachel Carlson]

Charles, what do we know about where inner speech comes from and what parts of the brain are involved?

[Charles Fernyhough]

Well, if you watch any small child, you're really likely to see them talking to themselves.

[Rachel Carlson]

Yes.

[Charles Fernyhough]

So when kids are talking to themselves out loud, we call that private speech. And the idea is that it's the precursor. It's the thing that comes before inner speech. So the inner speech that you and I probably experience or may not, where that comes from developmentally is from private speech. And in turn, that private speech came from the social dialogues that those that that kid enjoyed when they were growing up. So, you know, talking to caregivers, other adults, other children, and gradually internalizing those conversations, they become conversations with the self.

[Rachel Carlson]

Wow.

[Emily Kwong]

You're saying basically, like, because we're born into this social world with all these people around, like my niece's little monologue when she's, like, talking to herself will eventually become internalized, and that is her inner speech.

[Charles Fernyhough]

Yeah, exactly. That is the. It's the theory of a great Russian psychologist called Lev Vygotsky, who was writing this stuff about 100 years ago. His work has become increasingly influential in recent years. And it's a really simple, neat little theory that nobody's got to the bottom of yet because it is so rich, it has such implications for the way our minds work. Hmm.

[Rachel Carlson]

Where is that in the brain or where can we see it in the brain?

[Charles Fernyhough]

Well, as you'd expect, you see the language systems that we know about mostly lateralized onto the left hemisphere, a bit of towards the front called Broca's area, which is often involved in producing, you know, complex action patterns. A bit further back, called Wernicke's area, which is responsible for processing speech, including speech from other people. Those two areas create a kind of resonating loop which always shows up when we ask people to speak to themselves or out loud in the scanner.

[Emily Kwong]

What kind of scanner? Like a CT scanner, an MRI scanner.

[Charles Fernyhough]

These days it's going to be an MRI scanner. Yeah. When we're doing Fmri Research on the topic. So we see those systems lighting up. But, I mean, that bit at the front. Broca's area lights up when we do a whole load of different things. So we can't really pin too much onto that. So we know it's important, but it's not the whole story.

[Rachel Carlson]

How so?

[Charles Fernyhough]

So one of the things that we've argued, you know, if inner speech comes from a dialogue with other people, it should have the structure of a dialogue. In order to do that, your language system has got to be working. All that stuff on the left hemisphere that you'd expect to be working, but some other stuff must be going on as well.

[Rachel Carlson]

Oh, interesting. Okay, so you're saying that would involve more parts of the brain than just the language areas.

[Charles Fernyhough]

Yeah. And what we find when we look at people doing dialogic in a spir, as opposed to something that's more like a single line of conversation, is that, yes, you get that language system in the left hemisphere firing, but you also get another region way on the other side of the brain, which we know from previous research is involved in representing other people's minds. So you're representing yourself as a partner in that conversation.

[Commercial Announcer]

Wow.

[Emily Kwong]

Wow. We heard from Russell Hurlburt how there's, like, limits to surveying. Like, you can't really know what's going on in someone's inner experience fully, nor can they. How has the addition of scanning deepened our understanding of inner speech or complicated it to the point where maybe there's even more that we don't know?

[Charles Fernyhough]

The cool thing about working with Russ was that we had a study where we got people used to using descriptive experience sampling.

[Emily Kwong]

The beeper.

[Charles Fernyhough]

Yeah, the beeper. Yeah, they got used to using the beeper. Once they got pretty good at it, we then put them into the scanner and we saw what they were doing. So we had two kinds of inner speech. We sort of caught two kinds of fish. One is the elicited inner speech, where you're told to do it, and the other is the spontaneous inner speech, where you're not told to do it. It just happens. And we could look to see whether these two kinds of things were the same. And we've got a whole lot further to do on this topic. But what we found is they didn't look the same in terms of that balance of activation between Broca's area and Wernicke's area. So when we had elicited in a speech, there was lots of that Broca's area, the bit at the front on the Left, that's producing, producing, you know, doing these high complex movement patterns, including speech. But when people were doing inner speech spontaneously, there was much less of that.

[Emily Kwong]

Just like chilling in the machine. And they just had an errant thought that was inner speech.

[Charles Fernyhough]

Exactly. And it was more of that. That region a bit further back, the Wernicus area.

[Rachel Carlson]

Wow.

[Charles Fernyhough]

That was more the kind of listening, heary bit of the brain, you know, that the exact areas of the brain doesn't matter too much. But for us, it was a really important sign that more needed to be done here and that we shouldn't assume that when you put somebody in the scanner and tell them to do something, the thing that results is anything like the thing you're actually interested in. So, neuroscientists, beware. Are people really doing the kind of thing in the scanner that you want them to be doing?

[Rachel Carlson]

Yeah, yeah.

[Emily Kwong]

I mean, that inner speech, like spontaneous inner speech, sounds like birding. You scientists have to patiently wait and see if a bird shows up, but

[Rachel Carlson]

the bird is your own brain.

[Charles Fernyhough]

I love it. Yeah, exactly.

[Rachel Carlson]

I mean. Okay, so you also lead this project on voice hearing. So can you just tell us what voice hearing is and how it differs from spontaneous inner speech?

[Charles Fernyhough]

So we use the term voice hearing to describe the experience of hearing a voice when there's nobody around to have produced that voice. And we usually associate it with severe mental illness, so diagnoses like schizophrenia. What we've learned is that this experience happens to all sorts of people in all sorts of walks of life. Many, if not most, psychiatric disorders have voice hearing associated with them. But then there are a significant number of people who hear voices, who are not distressed by them, who don't seek psychiatric help, who don't need psychiatric help because they're not distressed, but find them useful, creative, guiding, spiritual, all these kinds of things. So the question of how that relates to inner speech. The theory is that when somebody hears a voice, what's actually happening is that they're producing some inner speech. So they're talking to themselves, but for some reason, that is not experienced as their own voice. It's experienced as coming from some sort of other entity or some sort of other place. And there's a good neuroscientific theory of why that works. And it goes back to those two parts of the brain. In fact, that bit Broca at the front, that bit Wernicke a bit further back. The idea is that when, usually when you're speaking, that bit at the front sends a little internal message to that bit in the Middle and says you're about to speak. Don't pay too much attention to it. Don't kind of process this like you'd process somebody else speaking because it's just you. And the idea is that in the case of voice hearing, that message doesn't get through in the same way. It's delayed or it's degraded or it doesn't happen at all.

[Rachel Carlson]

Wow.

[Emily Kwong]

So your brain can't tell it's you who's talking.

[Charles Fernyhough]

Yeah, pretty much. Yeah.

[Rachel Carlson]

What's the difference between that and not having inner speech?

[Charles Fernyhough]

The work that Russ has done and the work that I've done with him has made it really obvious to me that some people don't use inner speech very much. Maybe some never use it at all. They do other things.

[Emily Kwong]

Yeah, yeah.

[Charles Fernyhough]

They use images, they use music, they use emotions. They use all the other stuff that's going on in your head. It's also made it obvious to me that we're really bad at judging what's going on in our heads.

[Emily Kwong]

But if. If speech is just a tool, do you think that an adult can develop their inner speech? Like, is it. Is it better to have one?

[Charles Fernyhough]

I'd like to celebrate the diversity of human minds. I think we are so different.

[Rachel Carlson]

I think that's beautiful.

[Charles Fernyhough]

I think it's wonderful that there is this diversity and we. And we can celebrate that diversity. I wouldn't ever want to set out and say to people that they should improve their inner speech, but what I would say is that sometimes inner speech can have a negative side. And if your inner speech is bothering you, if it's excessively critical, you know, it can be wrapped up in all kinds of stuff that isn't particularly good for your mental health. And I'd say if. If that's bothering you, there are maybe things that you can do to. To rethink it. And if people have any concerns or want to know more about hearing voices, we have a website called understandingvoices.com where you'll find a whole bunch of different kinds of information about voice hearing, including how people make sense of voice hearing, what people do to seek help for voice hearing, and so on.

[Emily Kwong]

Charles Fernio, thank you so much for coming on Short Wave to talk about this. I think Rachel and I are a little speechless.

[Rachel Carlson]

I'm speechless. Yeah.

[Charles Fernyhough]

Thank you both.

[Emily Kwong]

This episode was produced by none other than Rachel Carlson. She really does it all.

[Rachel Carlson]

Thank you. It was edited by our showrunner, Rebecca Ramirez, and fact checked by Tyler Jones.

[Emily Kwong]

Kwesi Lee was the audio engineer, and Beth Donovan is our vice president of podcasting. I'm Emily Kwong.

[Rachel Carlson]

And I'm Rachel Carlson.

[Emily Kwong]

Thanks for listening to Short Wave from NPR Foreign.

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[Rachel Carlson]

Eduardo.