I am 100% bereft of mental imagery in a waking state of consciousness (I have fully sensory dreams when I sleep). It is dark and quiet in my mind all the time. Thoughts take the form of silently talking to myself. There are only words. No visual memory, no imagination—I don’t know what these things are, they are only words. Seeing things in the mind, hearing things, re-experiencing, exploring non-physical possibilities via imagination: these all sound like paranormal or supernatural experiences to me, literally, because what is normal and natural for me is the dark and quiet mind.
I find it fascinating how the Typical Mind Fallacy works both ways here: many mentally blind people say that they had no idea that other people could actually see pictures in the mind—this sounds so preposterous to us that, until some point when we break through our denial, we believe that people are speaking metaphorically about the “mind’s eye” or “picturing” something… because obviously it’s impossible! And the scientific community is largely unaware of the existence of non-imagers, because whenever they show up as research subjects, their self-reports of mental blindness tend to get discounted or ignored—again, because the researchers are committing the Typical Mind Fallacy—that can’t be true!
So I am writing a book about mental blindness. The book, tentatively titled “Mental Blindness and the Typical Mind Fallacy” will present the history of the non-study of non-imagery (due to the TMF), and characteristics of non-imagers, including some of the emotional and psychological aspects of living with this kind of cognition.
I’ve created a research survey to collect information from others who are non-imagers, or nearly so. To take the survey, click on this link: http://www.surveymonkey.com/s/RQXHZZQ
You are invited to participate in this survey if you fall into one of the following categories:
Non-Imager: you never experience any visual mental imagery in a waking state of consciousness; your mind is always dark, there is nothing picture-like that happens in your mind, either willed or unwilled. You have no sense of having a “mind’s eye.”
Weak-Imager: if there is any visual imagery, it is so vague or fleeting that you do not make use of it in purposeful, constructive thought processes: you do not use imagery for problem solving, memories are not visual, there is no visual component to imagining or daydreaming or planning. You experience a “mind’s eye,” but yours is more or less “legally blind.”
That’s the really sad part: no mental imagery with hallucinogens! Peyote, ayahuasca: nada, my hopes were dashed. The only effects with peyote, in meetings of the Native American Church, were a sense of connection and surrender, but there was nothing in terms of enhanced cognition. With ayahuasca, with a Huni Kuin shaman in Brazil, my mind dissolved into a state of bliss, but there was no imagery whatsoever—my mind was as dark as always.
My first ayahuasca ceremony was a personal healing for me, to rewire my brain and activate the missing part of my mind. I felt like there were psychedelic shapes coming into my head but I couldn’t see them; it was like knowing that something is there in the dark. It reminds me of when I gave a massage to a deaf client, who told me that she could feel the music during the massage and almost thought she was hearing it, but she couldn’t actually hear it. It gave my brain something to work with, it was the start of the rewiring process. I could feel the brain working hard to learn how to see, but it didn’t happen. No sense of journeying, just sitting in a state of nothingness.
My second ayahuasca experience, the following day with the same shaman, was a group ceremony. Here’s an excerpt from my journal from that ceremony:
“Ayahuasca told me that I am such an adept Buddhist and such an efficiency expert that I developed a method of staying glued to the present: I limited my neurological functioning in a way that prevents distraction of memory or other cognitive distractions. I am so devoted to the growth of my consciousness that I disabled the ability to recall past experiences or project myself into the future, or entertain myself with pictures or noises in my head. An evolutionary neurological mechanism to guarantee total focus! Because all experience of memory, all visualization, etc. is a distraction from present consciousness, and it is unnecessary! A brilliant spiritual solution that I devised for myself in this lifetime to learn presence. Bliss is the only thing that is real; all else is illusion and distraction. Even when Ayahuasca is activated in me, I don’t journey to other places, I don’t watch psychedelic video, I just remain present in the experience. What an extraordinary gift I have given to myself.”
But even so, i continue to feel that something essential is missing from my experience as a human being, and I continue to search for activation of mental imagery.
I don’t know if you’re still active on Lesswrong, but I wonder some things about ayahuasca. Hearing about it, I’m tempted to travel to Kapitari and take part in a ceremony. I’m cautious because of the fragility of the mental state, but then again, it may be healing.
My first ayahuasca ceremony was a personal healing for me, to rewire my brain and activate the missing part of my mind
Can you explain what you mean by activate the missing part of your mind?
Ayahuasca told me
What do you mean by told you? And how would that compare with other forms of telling, in intensity or whatever other dimension you can describe
Also, I feel that you’re writing here is somewhat unusual and abstract. I have noticed that in many writings by psychadelics users, and fear that I will become less capable of communicating effectively after use.
Thoughts from anyone else?
edit 1: also considering mushrooms more locally. a classmate’s boyfriend found and enjoyed some. thoughts?
Wow, the part you quote is fascinating. I would suggest what is missing is simply an ability to understand that the “present” you remain in is you alone, sharply defined. Once you let go or are forced to let go, you will be us. Perhaps I have been reading too much Christian de Quincey though......
If you will pardon the digression I’d love to ask you a few questions.
Can you still experience sensory information for a moment after the source is no longer present? For example, if you focus on an object and suddenly close your eyes, can you still perceive the object for fractions of a second?
If you don’t hear things in your mind does that mean you never have a song stuck in your head?
For me, a really useful purpose for visualization is for triggering related memories. For example, if I am trying to remember what groceries I need to buy, I will picture my refrigerator and mentally scan over the shelves to help myself recall what items usually reside there. What would you do in a situation like this?
Can you visualize spaces with object shapes and positions as distinct from images where you have to worry about color and more precise details of perspective? For me this is much easier than visualizing images.
You say your thoughts take the form of “silently talking to myself. There are only words. ” Don’t you ever sometimes think with concepts in place of words?
You may be interested that some people dream in black and white.
No, no lingering sensory information after the stimulus is gone. It’s like the mental sensory display mechanism is turned off: in the absence of a physical stimulus for physical sensory perception, there is no way to experience anything sensory in the mind.
I can get a song stuck in my mind, kind of, but it is not auditory—it is silent! And it’s not really stuck, I don’t think—it’s something that I find so compelling that some part of me wants to continue repeating it. Another part of me can stop it. It is not auditory, it is just words, and it is the same mental mechanism that is used for any other thought processes. And it cannot multitask, so if I start thinking about something other than the song (with my silent word thinking), then I can’t be singing the words to a song. Both my normal thinking and thinking a song are like conversations that I am having with myself, and I can’t talk about two things at once. They are not using any sensory channel, they only use the silent verbal channel, and that channel can only be occupied by one train of thought at a time.
About visualizing spaces with object shapes and positions: there is no visualization whatsoever, so no. People talk about seeing things on a “screen” in the mind’s eye. I have no sense even of there being a screen, much less anything on it. It is like a TV that is turned off.
I don’t believe that I have any way of thinking in concepts instead of words. There needs to be some vehicle for the concept, and silent words are the only vehicle that I have. When I am not thinking in words, the mind is empty.
About grocery shopping: I stand in my kitchen, look in the fridge and make a list before I go out. Otherwise I am screwed! If I don’t have a list, I’ll walk through the aisles looking at everything, wondering, is there anything I need? Or I might try to think about what i would like to eat, and wonder whether I have all the ingredients, and buy something that I’m not sure of. I might wonder if I’m missing anything for my morning smoothie, and remember that I used my last banana, but that is not any kind of an experiential memory—it is the memory, in words, of saying the words to myself “I need to buy more bananas” … because words and words alone are the fabric of my memory, as they are the fabric of all of my thought processes.
Yes, but very infrequently. Usually I wake up and know that I was dreaming, but have no way of latching on to any dream content, because my mind can’t re-experience any trace from a dream experience. The only traces that I have from dreams upon waking are either mental notes in the form of words, or emotional reactions in my body, e.g. heart pounding or solar plexus in a knot. Mental notes take the form of words spoken in the dream that were extremely compelling. So, for example, I know that I have visual dreams because once I woke up with these words lingering in my head from a dream: “Look, there’s a tornado coming this way!” I have no visual recall of seeing a tornado, because my mind doesn’t display visuals.
My favorite dreams were several that I’ve had in the past couple of years with this theme: in the dream, I have my eyes closed, and I see something in my mind! This is incredibly exciting to me. I wake up thinking the words that I spoke in the dream: I’m seeing something inside my head! It’s a picture of a woman! It’s in my mind’s eye! -- but I don’t know anything more than that, because those were the only words that I spoke about the mind picture; I don’t know whether it was a still snapshot or a video of a woman, whether she was riding a bike or sitting down, etc. Once or twice I’ve had a dream in which, with my eyes closed, the mind’s eye was seeing what I would have been seeing if my eyes were open—only I was seeing it with my mind, not with my physical eyes.
That’s interesting. You’re pretty much the opposite of me, then. I experience a wide variety of mental images, sounds, etc. I get a lot out of visual images of things, and I imagine written stories as if they are movies in my head. However, if there is a very technical idea that I can’t visualize either directly or indirectly, I usually struggle to understand it. For example, I am very interested in math and science and also have reason to use them on a daily basis (I am a software engineer who has a lot of scientific hobbies). But I almost always try to understand these topics through charts, graphs, geometry, tree structures, and other types of visualizations of the concepts. I posted a little on the topic how my thought processes work in this article, if you’re curious.
I’m curious about how you process information internally. What methods do you find most effective for learning new material? And for recreation, what is your experience of reading a novel vs seeing a movie? Also, feel free to use those questions on your survey if you’re also interested in other people’s answers to them (I realize the first one is related to a question you ask on your survey, although asking about it from a slightly different angle.
Hi Christina, I learn by memorizing words about things: verbal descriptions, procedures, narratives. There are a lot of things that I don’t try to learn because my mind can’t accommodate them effectively in words, e.g. abstract subjects like biochemistry and physics. There are a lot of things that I have to relearn from scratch again and again, such as medicinal properties of herbs, or the names and locations and characteristics of acupressure points. If a procedure is very complicated or hard to describe in words (too many words to memorize), I just don’t have a way to learn it. I am much more effective at learning hands-on things than learning about things that I can’t see (which is why I am a massage therapist and not a physicist!)
There is some motor memory, but only when I have performed an action often enough for it to become automatic, e.g. riding a bike. As a massage therapist, I studied Esalen massage, where the therapist is not working in a premeditated way—there is no sequence of moves like Swedish massage, rather exploring and listening and responding to the body in a fairly ad hoc way. There is one Esalen massage procedure that I would love to do but could never learn, because it involves a specific sequence of several very exact moves, to flip the body from a prone to supine position without the client falling off the massage table :-) I was never in a position to write down all the moves while observing it in class, so I could never practice it or duplicate it on my own.
Reading a novel or watching a movie is a lot like other things in my life: I am only engaging in the current moment of it mentally, the preceding parts are gone, because there is no way to hold on to them mentally. In order to watch a movie or read a novel, I make the effort the keep a running memorization going of a few key plot points in order to process the story. As soon as the movie is over or I’ve put the book down, it’s basically gone from my consciousness, unless I try to think about it or talk about it, and then I only have access to those points that I memorized in order to keep up with the plot, which is a very bare-bones summary.
I often have this sort of experience: I remember that I last night I read maybe a hundred pages of a book that I was enjoying a lot, so I want to finish the book tonight. Hmmm, I wonder, before I walk into the bedroom to retrieve the book, I wonder what I was reading? It was a story about… about… rats, I have no idea what it was, I’ll just have to go see!
While watching a movie, I have a hard time keeping characters straight unless they are actors that I recognize. I can remember—the blonde woman is the husband’s sister… then in the next scene, if there is a blonde woman, I think: she’s blonde, is she the sister or she someone else who is blonde? So I have to memorize words describing enough distinct visual characteristics in order to know for sure who’s who. It gets to be tedious sometimes, until enough of the movie has gone by that some recognition may kick in. There have been some movies that I’ve watched where there are, say, three main characters that are women, and they are all blond, thin, pretty. I can’t find any words to distinguish them, so for the entire movie, I have no idea who’s who. (unless there are some consistent, distinctive behavioral characteristics, like the pretty thin blonde who is angry and sarcastic. but then, through the magic of character growth, if she becomes nice, I don’t know who she is!)
I was shocked to learn several years ago that other people have visuals while reading. A friend asked me, “How can you read literature?” and it made me sad, because I love literature and never realized that there could be a whole extra dimension to it. I don’t actually know what imagination is like, so I can’t imagine what one might imagine while reading a novel! For me it’s just words and plot points.
I am 100% bereft of mental imagery in a waking state of consciousness (I have fully sensory dreams when I sleep). It is dark and quiet in my mind all the time. Thoughts take the form of silently talking to myself. There are only words. No visual memory, no imagination—I don’t know what these things are, they are only words. Seeing things in the mind, hearing things, re-experiencing, exploring non-physical possibilities via imagination: these all sound like paranormal or supernatural experiences to me, literally, because what is normal and natural for me is the dark and quiet mind.
I find it fascinating how the Typical Mind Fallacy works both ways here: many mentally blind people say that they had no idea that other people could actually see pictures in the mind—this sounds so preposterous to us that, until some point when we break through our denial, we believe that people are speaking metaphorically about the “mind’s eye” or “picturing” something… because obviously it’s impossible! And the scientific community is largely unaware of the existence of non-imagers, because whenever they show up as research subjects, their self-reports of mental blindness tend to get discounted or ignored—again, because the researchers are committing the Typical Mind Fallacy—that can’t be true!
So I am writing a book about mental blindness. The book, tentatively titled “Mental Blindness and the Typical Mind Fallacy” will present the history of the non-study of non-imagery (due to the TMF), and characteristics of non-imagers, including some of the emotional and psychological aspects of living with this kind of cognition.
I’ve created a research survey to collect information from others who are non-imagers, or nearly so. To take the survey, click on this link: http://www.surveymonkey.com/s/RQXHZZQ
You are invited to participate in this survey if you fall into one of the following categories:
Non-Imager: you never experience any visual mental imagery in a waking state of consciousness; your mind is always dark, there is nothing picture-like that happens in your mind, either willed or unwilled. You have no sense of having a “mind’s eye.”
Weak-Imager: if there is any visual imagery, it is so vague or fleeting that you do not make use of it in purposeful, constructive thought processes: you do not use imagery for problem solving, memories are not visual, there is no visual component to imagining or daydreaming or planning. You experience a “mind’s eye,” but yours is more or less “legally blind.”
many thanks Linda
I wonder what would happen if you took hallucinogens. Have you ever tried any?
That’s the really sad part: no mental imagery with hallucinogens! Peyote, ayahuasca: nada, my hopes were dashed. The only effects with peyote, in meetings of the Native American Church, were a sense of connection and surrender, but there was nothing in terms of enhanced cognition. With ayahuasca, with a Huni Kuin shaman in Brazil, my mind dissolved into a state of bliss, but there was no imagery whatsoever—my mind was as dark as always.
My first ayahuasca ceremony was a personal healing for me, to rewire my brain and activate the missing part of my mind. I felt like there were psychedelic shapes coming into my head but I couldn’t see them; it was like knowing that something is there in the dark. It reminds me of when I gave a massage to a deaf client, who told me that she could feel the music during the massage and almost thought she was hearing it, but she couldn’t actually hear it. It gave my brain something to work with, it was the start of the rewiring process. I could feel the brain working hard to learn how to see, but it didn’t happen. No sense of journeying, just sitting in a state of nothingness.
My second ayahuasca experience, the following day with the same shaman, was a group ceremony. Here’s an excerpt from my journal from that ceremony:
“Ayahuasca told me that I am such an adept Buddhist and such an efficiency expert that I developed a method of staying glued to the present: I limited my neurological functioning in a way that prevents distraction of memory or other cognitive distractions. I am so devoted to the growth of my consciousness that I disabled the ability to recall past experiences or project myself into the future, or entertain myself with pictures or noises in my head. An evolutionary neurological mechanism to guarantee total focus! Because all experience of memory, all visualization, etc. is a distraction from present consciousness, and it is unnecessary! A brilliant spiritual solution that I devised for myself in this lifetime to learn presence. Bliss is the only thing that is real; all else is illusion and distraction. Even when Ayahuasca is activated in me, I don’t journey to other places, I don’t watch psychedelic video, I just remain present in the experience. What an extraordinary gift I have given to myself.”
But even so, i continue to feel that something essential is missing from my experience as a human being, and I continue to search for activation of mental imagery.
I don’t know if you’re still active on Lesswrong, but I wonder some things about ayahuasca. Hearing about it, I’m tempted to travel to Kapitari and take part in a ceremony. I’m cautious because of the fragility of the mental state, but then again, it may be healing.
Also, I feel that you’re writing here is somewhat unusual and abstract. I have noticed that in many writings by psychadelics users, and fear that I will become less capable of communicating effectively after use.
Thoughts from anyone else?
edit 1: also considering mushrooms more locally. a classmate’s boyfriend found and enjoyed some. thoughts?
Wow, the part you quote is fascinating. I would suggest what is missing is simply an ability to understand that the “present” you remain in is you alone, sharply defined. Once you let go or are forced to let go, you will be us. Perhaps I have been reading too much Christian de Quincey though......
If you will pardon the digression I’d love to ask you a few questions.
Can you still experience sensory information for a moment after the source is no longer present? For example, if you focus on an object and suddenly close your eyes, can you still perceive the object for fractions of a second?
If you don’t hear things in your mind does that mean you never have a song stuck in your head?
For me, a really useful purpose for visualization is for triggering related memories. For example, if I am trying to remember what groceries I need to buy, I will picture my refrigerator and mentally scan over the shelves to help myself recall what items usually reside there. What would you do in a situation like this?
Can you visualize spaces with object shapes and positions as distinct from images where you have to worry about color and more precise details of perspective? For me this is much easier than visualizing images.
You say your thoughts take the form of “silently talking to myself. There are only words. ” Don’t you ever sometimes think with concepts in place of words?
You may be interested that some people dream in black and white.
No, no lingering sensory information after the stimulus is gone. It’s like the mental sensory display mechanism is turned off: in the absence of a physical stimulus for physical sensory perception, there is no way to experience anything sensory in the mind.
I can get a song stuck in my mind, kind of, but it is not auditory—it is silent! And it’s not really stuck, I don’t think—it’s something that I find so compelling that some part of me wants to continue repeating it. Another part of me can stop it. It is not auditory, it is just words, and it is the same mental mechanism that is used for any other thought processes. And it cannot multitask, so if I start thinking about something other than the song (with my silent word thinking), then I can’t be singing the words to a song. Both my normal thinking and thinking a song are like conversations that I am having with myself, and I can’t talk about two things at once. They are not using any sensory channel, they only use the silent verbal channel, and that channel can only be occupied by one train of thought at a time.
About visualizing spaces with object shapes and positions: there is no visualization whatsoever, so no. People talk about seeing things on a “screen” in the mind’s eye. I have no sense even of there being a screen, much less anything on it. It is like a TV that is turned off.
I don’t believe that I have any way of thinking in concepts instead of words. There needs to be some vehicle for the concept, and silent words are the only vehicle that I have. When I am not thinking in words, the mind is empty.
About grocery shopping: I stand in my kitchen, look in the fridge and make a list before I go out. Otherwise I am screwed! If I don’t have a list, I’ll walk through the aisles looking at everything, wondering, is there anything I need? Or I might try to think about what i would like to eat, and wonder whether I have all the ingredients, and buy something that I’m not sure of. I might wonder if I’m missing anything for my morning smoothie, and remember that I used my last banana, but that is not any kind of an experiential memory—it is the memory, in words, of saying the words to myself “I need to buy more bananas” … because words and words alone are the fabric of my memory, as they are the fabric of all of my thought processes.
Have you ever experienced anything from a dream? Remembered words from it, or woken up afraid, so you know you were probably having one, or anything?
Yes, but very infrequently. Usually I wake up and know that I was dreaming, but have no way of latching on to any dream content, because my mind can’t re-experience any trace from a dream experience. The only traces that I have from dreams upon waking are either mental notes in the form of words, or emotional reactions in my body, e.g. heart pounding or solar plexus in a knot. Mental notes take the form of words spoken in the dream that were extremely compelling. So, for example, I know that I have visual dreams because once I woke up with these words lingering in my head from a dream: “Look, there’s a tornado coming this way!” I have no visual recall of seeing a tornado, because my mind doesn’t display visuals.
My favorite dreams were several that I’ve had in the past couple of years with this theme: in the dream, I have my eyes closed, and I see something in my mind! This is incredibly exciting to me. I wake up thinking the words that I spoke in the dream: I’m seeing something inside my head! It’s a picture of a woman! It’s in my mind’s eye! -- but I don’t know anything more than that, because those were the only words that I spoke about the mind picture; I don’t know whether it was a still snapshot or a video of a woman, whether she was riding a bike or sitting down, etc. Once or twice I’ve had a dream in which, with my eyes closed, the mind’s eye was seeing what I would have been seeing if my eyes were open—only I was seeing it with my mind, not with my physical eyes.
It has more than three years from the date you commented. What is the status on the book? Is it in print now?
Hi, Linda.
That’s interesting. You’re pretty much the opposite of me, then. I experience a wide variety of mental images, sounds, etc. I get a lot out of visual images of things, and I imagine written stories as if they are movies in my head. However, if there is a very technical idea that I can’t visualize either directly or indirectly, I usually struggle to understand it. For example, I am very interested in math and science and also have reason to use them on a daily basis (I am a software engineer who has a lot of scientific hobbies). But I almost always try to understand these topics through charts, graphs, geometry, tree structures, and other types of visualizations of the concepts. I posted a little on the topic how my thought processes work in this article, if you’re curious.
I’m curious about how you process information internally. What methods do you find most effective for learning new material? And for recreation, what is your experience of reading a novel vs seeing a movie? Also, feel free to use those questions on your survey if you’re also interested in other people’s answers to them (I realize the first one is related to a question you ask on your survey, although asking about it from a slightly different angle.
Hi Christina, I learn by memorizing words about things: verbal descriptions, procedures, narratives. There are a lot of things that I don’t try to learn because my mind can’t accommodate them effectively in words, e.g. abstract subjects like biochemistry and physics. There are a lot of things that I have to relearn from scratch again and again, such as medicinal properties of herbs, or the names and locations and characteristics of acupressure points. If a procedure is very complicated or hard to describe in words (too many words to memorize), I just don’t have a way to learn it. I am much more effective at learning hands-on things than learning about things that I can’t see (which is why I am a massage therapist and not a physicist!)
There is some motor memory, but only when I have performed an action often enough for it to become automatic, e.g. riding a bike. As a massage therapist, I studied Esalen massage, where the therapist is not working in a premeditated way—there is no sequence of moves like Swedish massage, rather exploring and listening and responding to the body in a fairly ad hoc way. There is one Esalen massage procedure that I would love to do but could never learn, because it involves a specific sequence of several very exact moves, to flip the body from a prone to supine position without the client falling off the massage table :-) I was never in a position to write down all the moves while observing it in class, so I could never practice it or duplicate it on my own.
Reading a novel or watching a movie is a lot like other things in my life: I am only engaging in the current moment of it mentally, the preceding parts are gone, because there is no way to hold on to them mentally. In order to watch a movie or read a novel, I make the effort the keep a running memorization going of a few key plot points in order to process the story. As soon as the movie is over or I’ve put the book down, it’s basically gone from my consciousness, unless I try to think about it or talk about it, and then I only have access to those points that I memorized in order to keep up with the plot, which is a very bare-bones summary.
I often have this sort of experience: I remember that I last night I read maybe a hundred pages of a book that I was enjoying a lot, so I want to finish the book tonight. Hmmm, I wonder, before I walk into the bedroom to retrieve the book, I wonder what I was reading? It was a story about… about… rats, I have no idea what it was, I’ll just have to go see!
While watching a movie, I have a hard time keeping characters straight unless they are actors that I recognize. I can remember—the blonde woman is the husband’s sister… then in the next scene, if there is a blonde woman, I think: she’s blonde, is she the sister or she someone else who is blonde? So I have to memorize words describing enough distinct visual characteristics in order to know for sure who’s who. It gets to be tedious sometimes, until enough of the movie has gone by that some recognition may kick in. There have been some movies that I’ve watched where there are, say, three main characters that are women, and they are all blond, thin, pretty. I can’t find any words to distinguish them, so for the entire movie, I have no idea who’s who. (unless there are some consistent, distinctive behavioral characteristics, like the pretty thin blonde who is angry and sarcastic. but then, through the magic of character growth, if she becomes nice, I don’t know who she is!)
I was shocked to learn several years ago that other people have visuals while reading. A friend asked me, “How can you read literature?” and it made me sad, because I love literature and never realized that there could be a whole extra dimension to it. I don’t actually know what imagination is like, so I can’t imagine what one might imagine while reading a novel! For me it’s just words and plot points.
Thanks for your detailed response! And upvoted since it gave me a lot to think about in regards to variations on how the mind works.
“Thoughts take the form of silently talking to myself.”
Is that not a form of “mental imagery”?