Monday, March 04, 2013

The Spatial Location of Inner Speech

Last night, my six-year-old daughter Kate told me she had a song "in her head". I asked her if it was really inside her head, and she said yes it was. I asked her how big it was. At first she said she didn't know, but when pressed she agreed that it was larger than a pea but smaller than a dog, and she spread her fingers a few centimeters apart.

Most of the people I've interviewed are willing to attribute a spatial location to their experience of inner speech and imagined tunes -- and that location is virtually always inside their heads, not in their tummies or their toes or out in the environment, unless it's a hallucination or a case in which they're not sure whether the origin is some subtle environmental sound. Why, I wonder, this uniformity of report?

You might say -- as my 13-year-old son Davy said later last night, when I interviewed him -- that it's experienced as in the head because its origin is in your brain, and your brain is in the head. But that argument can't work without some supplementation. Phantom-limb pain, for example, is experienced as spatially located outside the head, even if its origin is in the head (or in peripheral nerves closer to the center of the body). Visual experience is a product of the brain but not normally described as located in the head. Visual imagery, too, although often described as "in the head", is sometimes experienced as out in the environment. For example, I might imagine a demon crouching in the corner of my office as I now look into that very corner. Also -- somewhat surprisingly to me! -- when I interview people about their visual imagery experiences, about 25% describe their visual imagery as spatially located a few inches in front of the forehead. In contrast, I have never heard anyone describe their inner speech as transpiring a few inches in front of their forehead!

You might say that it's because the origin of our outwardly verbalized speech is our head, so we're used to locating our speech inside our heads. But that doesn't quite work either. When I speak, the spatial origin of the sound, it seems to me, is my mouth. Although that's part of my head, most people, when they locate their inner speech, locate it not in their mouths but in the interior of their cranium.

You might think that it makes sense that we would imagine music as transpiring in our cranium, since that's where it seems to be when you're listening with headphones. But that doesn't quite work either, I think, since people with limited exposure to headphones (like Kate), who hear most of their music from exterior sources, still report tunes as spatially interior. (I'd wager one finds this "inside the head" phenomenological positioning, too, if one looks at phenomenological reports in Anglophone culture pre-stereophonics, but I haven't done the search on that (yet).)

A more interesting possibility is this: Sometimes imagery is experienced as environmentally positioned -- like that demon in the corner of my office. We might imagine a representation like this {demon with properties a,b,c; egocentric location x,y,z}. But most of the time we don't visually imagine things as environmentally located, so the representation is just {demon with properties a,b,c}. Without an environmental position explicitly represented, we might default to representation at our subjective center -- either actually experiencing it as there or erroneously thinking we experience it as there. And maybe our subjective center is inside our cranium. But even if so, the view has problems accounting for visual imagery reported as in front of the forehead, and with reports of inner speech as moving around inside one's head (as some of Russ Hurlburt's interviewees report).

So I'm left still wondering....

18 comments:

Taylor said...

Reminds me of a post by Mohan Matthen on NewAPPS some time ago. No doubt the mechanisms differ between auditory and visual representations. We have two eyes and 3D vision, and the idea that a 3d image is not at some distance seems hard to imagine (but what about when you imagine seeing red and only red?). If it wasn't some distance away, I couldn't see all of it. Two point particles in the same position have an undefined field of view to each other, and add a second eye and a distance of 0 does not make sense-it's impossible. With audition, there is a solution to the localization that eliminates spatial localization in a way not found with 3D objects seen by two eyes. Set the distance to 0 and it is not infinitely loud, etc.

Note: iPad comments. Probably not coherent, but there's something in this vicinity.

Eric said...

I believe it has to do with the fact that we represent experience as occurring in some sort of "Theater of the Mind." I mean, we tend to imagine that there are all of these experiences parading in front of us, while we sit back and watch as some detached cogito. Given that vision is the most apparently primary sense (e.g., "light" is a symbol of consciousness in many unrelated religions), it makes sense to think that our "real" self is sitting right behind our eyes, looking out into the world. Obviously that picture is fallacious in more ways than one, but it seems like a natural picture nonetheless.

This is not exactly the same as saying "It is because visual experience is in the head." If we picture the eyeballs as some kind of window out of which we look, then it is perfectly consistent with this picture to say that what we see at least seems to be in front of our eyes, even if it is a hallucination or subjective image.

This explanation also makes sense of the fact that we can say that the visual image is in front of our head, but, acknowledging it to be subjective, we can add that it is really just in our heads. Similarly, it makes sense of the fact that we can consistently say both that the phantom-limb pain is experienced as occurring in the non-existent limb, and that it is really just in our heads.

Chris Bogart said...

I wonder how someone would answer this question if they were from a prescientific culture that believed the heart was the seat of consciousness. Is it possible they'd perceive inner speech as coming from inside their chests? E.g. there's a quote in in the Bible (Matthew 15:19) about evil thoughts coming from the heart, but I don't know what people at that time believed about anatomy, or if that author really felt like thoughts came from his chest.

Eric Schwitzgebel said...

Taylor: Interesting theory. I wonder what else it might predict? Would it be consistent with the common report that visual images are also inside the cranium? I don't know which NewAPPS post you're thinking of -- do you have a link?

Eric Schwitzgebel said...

Eric: Maybe so. How about smells? Too bad we don't have more reports of olfactory imagery to draw on. When I imagine the smell of fresh-baked bread, is there a subjective position of the olfactory image? Is there a spatial position even for ordinary olfactory sensory experience?

Eric Schwitzgebel said...

Chris: Yes, an interesting question. I've thought about it a bit in connection with Chinese philosophy. Mengzi, etc., actually did literally think of the heart as the seat of cognition. Unfortunately, there isn't a lot of phenomenological reporting from that era to draw upon! I'd be interested in textual evidence if anyone knows of some.

Carl M. said...

Self-Phenomenological Report Time:

Can you all imagine seeing something behind you? Closing my eyes and imagining seeing an object in front of me is quite simple, but imagining the object as presenting itself as *behind* me is much more difficult, and I'm not sure it has the same level of imaginative details an imagined object in front of me.

Joseph Edmund Dewhurst said...

Hi Eric,

First time commenter here, but a long time reader!

As I'm sure you're aware, Gilbert Ryle gives this some consideration in The Concept of Mind. I haven't got a copy handy, so I can't tell you exactly what he says, but it might be worth having another look at. All I can remember is that it's somewhere in the first couple of chapters...

Ryder Dain said...

For textual evidence of the heart as responsible for consciousness, there's a vague reference to that organ being responsible for thought in the "Sefer Yetzirah", which is a work from the judaic kabbalastic tradition:

(Verse 1:8) ... Bridle your mouth from speaking and your heart from thinking.

Not a lot to go on for the phenomenology, but so it goes.

Personally I have to say that when I'm speaking, I find myself either "reading from an internal script", where I've deliberated on the things I plan to say, or in other situations I find myself "speaking from the heart". In the latter case I feel that I'm not subjecting what I'm going to say to any internal deliberation, and in just these cases the phenomenology of the experience of speaking is markedly different - it feels like my whole body becomes involved (which is where, I suppose, the phrase could derive from).

For internal speech, as it necessarily requires that I deliberate on the things I would say, if I was "thinking aloud", then it normally feels more like the first case, where it's just that I'm actually imagining the sentences and propositions that I'm thinking about, as if written on a page, or heard from someone else - and I'd suggest that such deliberation requires an imagination of speech, which in turn needs to rely on some of the same mechanisms of the brain which we use when we see or hear things, and which are obviously internal to the space inside our skull. Hence, when we engage in internal speech, we employ our imagination of actual sense-perception going on, and it's the need of spatial representation for sense-perceptions that gives internal speech its spatial qualities.

Arnold Trehub said...

I think you can get a better grip on the problem if you consider the egocentric spaces of the self image and the outer phenomenal world in Fig. 1 here: http://evans-experientialism.freewebspace.com/trehub01.htm . Also consider the perspectival nature of the core self in our phenomenal world that is discussed here: http://theassc.org/documents/where_am_i_redux .

Eric Schwitzgebel said...

@ Arnold: I know you think that egocentric perspective is near the core of consciousness. Do you have anything on inner speech in particular?

@ Ryder: Thanks for the textual reference. Such thin remarks are unfortunately typical of related texts in the Chinese tradition. Hard to know how much to weigh them as real reports of phenomenology. On your concluding paragraph, I'm inclined to think that inner speech is often experienced as "from the heart" in the metaphorical sense as emotionally real and free of explicit deliberation (e.g., when I curse to myself) -- don't you think?

Taylor said...

Johan's post. M o h an. http://www.newappsblog.com/2012/06/minds-on-monday-perceptual-models-without-a-viewpoint.html

Speaking of which, I never provided citations for the olfaction stuff. Could get those on my laptop if anyone is interested.

Eric Schwitzgebel said...

@ Joseph: Thanks for the tip on Ryle. I hadn't recalled that part of the book! I'll see if I can dig up the refernece.

@ Carl: Interesting thought. I'm trying to visually imagine a demon creeping in my office door behind me. I seem to be visualizing it as though I were looking straight at the demon and then through some separate action (?) mapping that into egocentric space. I'm inclined to agree that it seems more complex than picturing the demon sitting in the corner I am gazing at -- though I don't feel confident in that judgment.

Interesting introspective experiment! I could imagine it causing trouble for or giving aid to various theories of visual imagery....

Howie Berman said...

Inner speech is in that little canal joining the ears and the mouth- there or in the Adam's Apple which is where outer speech is located

Arnold Trehub said...

@ Eric: "I'm trying to visually imagine a demon creeping in my office door behind me. I seem to be visualizing it as though I were looking straight at the demon and then through some separate action (?) mapping that into egocentric space. "

This is interesting. Seeing/visualizing something behind you violates an essential part of your self image. It seems that you have to *covertly* reorient yourself in your office in order to have a visual perspective on what is supposed to be in back of you. The same is true when I try it.

But sound is different. I can image the sound of a siren behind me (consistent with my self image). But the significant thing is that I can't image a fire engine sounding a siren behind me! It has to be in front of me. Does this happen with you?

Eric Schwitzgebel said...

Arnold: I think you might be right about that. That was my first instinct when I did that little imagery experiment. Now I find myself not so sure, though.

Also relevant: Galton's (1880, 1907) reports of people who say they imagine things from some all-encompassing point of view; and the fact that when I close one eye and press on the opposite corner of the other, the pressure phosphene appears in a dark spot as though interior from the nose, but I can never push it far enough in that it seems to be outside of the visual periphery defined by the far boundary of my other eye's visual field. (That was a little compressed, but it fits nicely with your view, so I think you'll get it.)

Charlie Chung said...

I think (and thought I read it somewhere a long time ago) that it is in fact located somewhere between the top of the oral cavity & between the ears and is due to not-fully-vocalized speech. The bones involved in hearing can still vibrate with this type of speech.

Personally, often it is very pronounced for me and I feel the air in my oral cavity and vocal chords/flaps move as I articulate this "inner speech".

Eric Schwitzgebel said...

Thanks for the interesting thought, Charlie! I'll have to take a look at the vibratory mechanics. Why not the neck -- isn't that still the principle locus of vibration? Do you have a reference to point me toward?