My concern is that if we take their word for it, we're actually buying into two assumptions which (AFAIK) are both unproven:
1. That "Internal Monologues" (not consciously forced by attention) exist in the first place, as opposed to being false-memories generated after-the-fact by our brain to explain/document a non-language process that just occurred. (Similar to how our conscious brains pretend that we were in control of certain fast reflexes.)
2. Some people truly don't have them, as opposed to just not being aware of them.
In short, maybe these inner monologues exist and maybe they don't, but science can't comment on that. That said, it is clearly something we are interested in, but it will need to be addressed in some other way (i.e. religion, ideology, etc.).
No, they are potentially falsifiable as we get better at scanning, identifying, intervening in brain activity.
Just off the top of my head here, suppose we create a table puzzle problem that (in itself) doesn't require language to understand, like ones we make for certain animals. Have human subjects (silently) solve it. Afterwards, quiz the solvers about their internal monologue--or lack thereof--dividing them into two groups and noting the words used.
Now change to a second puzzle of similar style and same overall difficult. Stun/anesthetize the language-centers of subjects, to deny access to any of the monologue-words (validating this intervention will involve other research), and then test them on the second problem.
* If performance is constant for both groups, that suggests the monologue is illusory or at least not needed for this kind/scope of problem.
* If performance drops for both groups, that suggests the no-monologue people might just not be as aware of a linguistic process that's actually happening.
* If performance drops for monologue-subjects, that suggests it's a real and important difference in modes of logical thought.
* If some other combination happens, you have an mysterious and exciting new line of research.
Individually, no, but in general, for people to consistently lie about this particular thing at scale would be extremely unusual, given that people rarely lie if there's no reason for it. Going by this baseline, you could assume upward of 50% of replies are honest (even if mistaken), otherwise you'd have to explain why do you believe people would suddenly lie about that particular thing.
There's conspiratorial lying and lying from ignorance, one is much less credulous.
For example, I can think of interpretations of "I picture objects that I'm thinking about" that range from me not experiencing the phenomenon to me indeed experiencing the phenomenon.
To say that you're not experiencing something that other people are experiencing in their head is a solipsistic notion where you hypothesize an experience that you imagine others are having and then discard it for being different than yours.
Then again, it's trivially reproducible - people self-report all variants of inner monologue, including lack of it, whenever a question about it pops up on-line. Same is the case with imagination - aphantasia is a thing (I would know, I have it).
That you and I can come up with different ways to describe our subjective experience in conversation doesn't mean that we have a different subjective experience.
Especially not when relayed by a species that's frequently convinced it has a trending mental disorder from TikTok.
Look up examples of this on reddit and you'll find a lot of larping. I would take most of it with a grain of salt as you should with any story-telling you encounter on social media.
If we're so reliable, there wouldn't be fake mental illness epidemics on TikTok regarding experiences far more concrete than fuzzy notions like inner monologue.
As someone who was involved in spiritual practice of "stopping internal dialogue" for years, I can tell you that one learns that that dialogue (or monologue, pretty much the same thing) is quite subtle and complex, essentially multi-layered.
Typically, when you think that you "think about nothing at all" it's just the most surface layer that has stopped, and more subtle talking to yourself is still going on. It takes training just to become able to notice and recognize it.
After all, it's just such a constant and monotone hum at the back of one's mind, one learns to completely ignore it.
So no, I would not take a word of people who were not trained to notice their internal monologue that they haven't any :-)
because if we give them a problem to solve in their head and just give us the answer, they will. By problem I mean planning a trip, a meal, how to pay the mortgage, etc. It's impossible to plan without an internal monologue. Even if some people claim theirs is 'in images'.
I'm the opposite. I rarely visualize things I read, be it geometry or poetry. I can read a detailed description of a person or an item in a novel, and I don't really "see" anything.
But I have an active inner monologue. I "hear" myself saying the words when reading or writing, I "talk" to myself when solving problems or just thinking about stuff.
Especially when programming I'm reasoning by discussing the problem with myself, the only difference being that I usually don't open my mouth and vocalize the discussion. Though sometimes when I'm alone I do just that.
Of course it isn't impossible, and this is backed by what we know about paleoanthropology and other instances of cognition in animals - humans were making stone tools millions of years ago, which takes planning in the form of imagining what you want the tool to look like and how you will do it and what it will be used for. It's exceedingly likely we had this ability long before complex speech evolved. Apes also use and make tools, which would require planning, and I don't think they have an internal monologue going on. birds from the corvid family can do some pretty advanced problem solving that requires planning. Cetaceans might be an exception, because they appear to have some form of language, but this is a pretty wild claim not really backed by any kind of science as we understand it today.
Also, maybe inner monologue is not a binary have/have not, but maybe it is on a continuum.
Instincts.
I once had a teacher claim that people who claimed to have aphantasia were lying, because those people have read books and it is impossible to read a book without picture the scene in your mind's eye. Are you citing the same source that she was?
That's quite the claim.
How can science make this claim if it can't prove (or disprove) the existence of an internal monologue?
He thought this was universal, but doing this experiment with friends, he discovered a guy who could count while reading aloud. So when Feynman asked him, how he does this, turned out that the guy instead of "pronouncing" numbers was "seeing" colored numbers in his imagination, so his speech was not involved.
I supposed this experiment can be modified and generalized, and at least to shed some light on this problem.