Email: John McCrone to Larry Victor
Subj: psyche discussion on imagery
Date: 7/15/02 6:57:28 AM US Mountain Standard Time From:
1 You posted to Psyche-D in May about "lacking imagery". I was expecting some kind of interesting thread to develop, but there was no follow-up. Can I ask a few questions as the mechanisms of imagery are central to my own descriptions of brain function?
2 Briefly I take the Ulric Neisser line that mental imagery is based on anticipation - "the first half of the perceptual cycle". So a mental image would be a sensory (or sensorimotor) expectation that does not then go on to develop into an actual explicit perception. We generate a state of expectancy (such as the expectation of being just about to see a friend's face, a pink elephant, our favorite tune) in the absence of a stimulus.
3 Because anticipation is taken to be a basic brain process - all brains must be able to produce states of expectation even to be able to do simple things like drive cars or play tennis - it would be considered "impossible" for a person to be without imagery. The alternatives would be -
4 1) The anticipatory states formed by the brain are weak in not being "fleshed out". So there would be inklings, a vague sense of orientation or readiness, a feeling of being "just about to see" the desired image. But there would not be a detailed and concrete sense of mental imagery - fixed pictures before the eyes.
5 The explanation here might be neurological. Most theories about anticipation/imagery production point to feedback circuitry between higher (memory) and lower (sensory) cortical areas as the means of causing sensory-type experiences to be recreated in sensory processing areas. Some people (the 10 percent of population who are highly hypnotizable and claim veridical imagery) may have a strong ability to drive the cortex into imagery states. Others may lie at the other end of the spectrum and lack the strong feedback connections.
6 2) Alternatively, the imagery may be present, but not subjectively noticed. There are people who don't notice their dreams or other mental phenomena until their attention is drawn to them. If a person has weakish mental imagery anyway, then it may have gone unnoticed as they were growing up. Imagery would be used to think, but the fact that it was being used would not be explicitly noticed. And imagery could not be conjured up on demand, only used as part of a train of thought. So turning to the detail of your post.........................
7 [Larry Victor] I have no sensory-like remembrances of my past. I don't know what my friends and family members look like - but I can recognize persons after some time knowing them.
8 [John McCrone] If you are asked question such as "what is the colour of your front door?", how do you arrive at an answer? Is there any sense of getting orientated to be seeing your front door? Or can't you answer such questions? Or if asked what you ate for breakfast?
9 Do you go through a list of things that you might have eaten before getting a somehow clearer feeling about having actually been eating a particular food? What makes the right answer seem like a right answer (if it is not a clearer mental image - a memory - of you in that situation)?
10 [Larry Victor] I also sense pre-imagery in my preconscious. Often I will sense it as a field of variations of what might be presented to consciousness, but there is no selection going on so nothing comes up.
11 [John McCrone] This would be what I describe as inklings, being on the brink of experiencing something. So you know when you are oriented, in a correct state of sensory preparation. But it does not then spill over into the generation of actual concrete imagery.
12 Would it be fair to say if mental imagery is defined in terms of sensory readiness - a clear preparedness for an experience - rather than just as concrete, sensory-strength images, then you would have "mental imagery" of this kind as a normal part of your thinking?
13 [Larry Victor] A few times a month before going to sleep my inner visual field will become bright with swirls of color for a few seconds. This is different from visuals made by pressing the eyeballs. Attempts to maintain the experience accelerates its disappearance. A few times a year I will have a very brief, very weak image - like black on black. Sometimes a face, or a body, or a landscape. Less than a second and without the focus and sharpness of "real" images. They are always too brief for "identification". But, I know they were there, and was pleased. In total dark my visual is usually deep black - but often with some weak texturing.
14 [John McCrone] This would be hypnogogic imagery - also called form constants. I think this differs from anticipation-based mental imagery in that it is not generated as part of a high-level state of expectation, instead it is just the pattern-forming play of lower sensory areas as the brain shuts down feedback connections (desynchronises) as part of falling asleep.
15 [Larry Victor] I discovered my lack of visual imagery while in graduate school in physics at the University of Chicago in 1957 when I was 22. It happened when I had a brief, intense visual image.
16 [John McCrone] Can you remember what it was of? Or know why it might have happened at that particular moment?
17 [Larry Victor] I have NEVER imaged even a simple melody in my head (I can hum them).
18 [John McCrone] This I found especially surprising as I find tunes are always sticking in my head. But it sounds like you can hum them, or sing them, in your inner voice? Just as you would be able to "hear" the thoughts expressed in you inner voice?
19 [Larry Victor] Nor can I image my body in positions or movements other than what it is doing. I even have weak body perception, I don't know where my feet are pointing without looking at them, which is a handicap if one attempts to ski.
20 [John McCrone] Does your lack of imagery cause many obvious problems with co-ordination? Or with memory - such as not being able to picture where you might have left your keys?
21 [Larry Victor] I frustrate greatly those experiential leaders who depend on forms of imagery (usually visual, auditory or movement). Often I discover others at such sessions who also fake it.
22 [John McCrone] I can sympathise here as although I have visual imagery, it is not as concrete as some. So I am hopeless when someone tries to hypnotise me or demonstrate techniques such as neuro-linguistic programming.
23 [Larry Victor] I speculate that the biological source of my lack of imagery relates to a need for the consciousness "screen" to be continually refreshed. When perceiving from my senses, energy from the continuing sensory stimulation keeps the "screen" refreshed. If the stimulus for the "screen" is internal and requiring feedback to maintain a pattern, the image on the screen could be too brief to be noted. This could be due to an internal erasure of weak neuronal resonances (mini shock treatments - possibly the origins of some EEG patterns), that for me is too powerful to permit images other than those in continuous reinforcement to exist long enough to be noticed.
24 Yes, this is the kind of story I would suggest. But my own view is that it would be not so much a need for continuous feedback pressure as more to do with an ability to constrain a vague state of anticipation, turning up the neural contrast so that a general expectation becomes a specific and concrete sensory representation.
25 The P300 literature lends support for this approach. Sharp states of experience are created by suppressing a surround of neural activity and emphasising a centre. So a person with strong imagery might have the equivalent of a high contrast button. A person with weak imagery might not be able to crank up the contrast production in a way that would cause a preconscious readiness to experience something to evolve into a vivid concrete image. Acetycholine and NMDA connections would seem to be implicated in this by P300 work.
26 To sum up, it sounds like you experience the kind of pre-imagery that I talk about - the feeling of being about to experience something (what you call a background of explicit "conceptual-emotive imagery"). So it is not that you don't have any mental imagery, but you don't have concrete, sensation-like, mental states. And this might be a much more common phenomenon among people than generally recognized.