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On Being Stoned, by Charles Tart

  On Being Stoned

    Charles T. Tart, Ph. D.

        Chapter 6.    Vision

MAN IS PRIMARILY a visual animal, both in terms of vision's being his primary and generally most efficient way of perceiving his environment, and in terms of visual styles' influencing his thinking, imagining, and conceptualizing. Changes in visual experience while intoxicated on marijuana are thus of particular interest. We shall first consider phenomena related to visual perception of the external world, then those related to visual imagery and hallucinations.



Form and Organization

    A very characteristic effect of marijuana intoxication is increased perceptual organization ("meaningfulness"): "I can see patterns, forms, figures, meaningful designs in visual material that does not have any particular form when I'm straight, that is just a meaningless series of shapes or lines when I 'm straight" (6%, 6%, 29%, 37%, 19%).[1] The modal minimal level of intoxication for this is Strongly (3%, 25%, 37%, 17%, 5%). The College-educated experience this more frequently than the Professionals (p <.05).
Note.—In interpreting the "How Stoned" graphs, note that the percentage of users plotted at each level is the percentage indicating that level as their minimal level of intoxication for experiencing that particular effect. Thus. a drop in the curve with increasing minimal level of intoxication does not mean that fewer users experience that effect at higher levels. but that fewer give a higher level as their minimal level for experiencing that effect.

    A common effect that also reflects this increased perceptual organization of the visual field is "Things seen are seen more sharply in that their edges, contours stand out more sharply against the background" (13%, 13%, 31%, 30%, 11%). The contrary effect, "My vision tends to be somewhat blurry; if I try to examine something visually, I can't focus as sharply as when straight" (32%, 29%, 25%, 9%, 3%) occurs much less frequently (p <.001), as shown in Figure 6-1. Blurriness of vision is associated with higher levels of intoxication (1%, 13%, 18%, 21%, 11%) than sharpening (6%, 41%, 24%, 10%, 2%), as shown in the figure (p <.001).
    Visual blurriness is reported somewhat more frequently by women than by men (p <.05), and is reported as occurring at lower minimal levels of intoxication by Occasional users in comparison to Weekly or Daily users (p <.05, overall).
    A fairly frequent effect that also illustrates reorganization of the visual field is "The face of another person will change even as I watch it, so he keeps changing from one different person to another" (36%, 21%, 23%, 11%, 6%). This is a high-level effect (2%, 3%, 11%, 19%, 17%), although many (47 percent) users did not rate level. Users of Psychedelics experience it more frequently than Non-users (p <.01). Meditators experience it more frequently than Ordinary Users (p < .05), with neither group significantly differing from the Therapy and Growth group.



    Like form, color is an important aspect of visual organization, and perceptual changes here are common: "I see new colors or more subtle shades of color than when I'm straight" (10%, 18%, 30%, 19%, 21%). The contrary effect, "Colors get duller, not as vivid," is rare (62%, 23%, 8%, 3%, 1%), as shown in Figure 6-2 (p <.001). Color perception is enhanced at low levels of intoxication (17%, 31%, 27%, 7%, 4%). Most users (67 percent) could not rate the minimal level for color dulling (6%, 13%, 6%, 5%, 3%), and this distribution of levels does not differ significantly from that reported for color enhancement.
    The Therapy and Growth group tends not to see new colors as frequently as the Meditators and Ordinary Users (p <.05, overall). The Professionals have to be more intoxicated than the College-educated for colors to get duller (p <.05).



    An important element of visual organization is the dimension of perceived depth. Four items deal with changes in perceived depth. We shall describe each separately before considering their interrelationships.     A common effect is "When I look at pictures they may acquire an element of visual depth, a third-dimensional aspect that they don't have when straight" (13%, 12%, 34%, 23%, 15%), which begins in the low-middle range of intoxication (4%, 26%, 32%, 12%, 7%). One of my informants, known for his excellent phenomenological description of marijuana intoxication (Anonymous, 1969), describes how dramatic this can be: if, while intoxicated, you look at a color photograph or picture postcard of a scene with natural depth in it, and look with one eye through a pin-hole close enough to the picture so that its borders cannot be seen, the two-dimensional representation will suddenly turn into three dimensions, as if you were looking at the actual scene.
    A converse and rare depth effect is "The world looks flat: it lacks the third dimension of depth" (55%, 27%, 9%, 5%, 1%). Most users (61 percent) did not rate the intoxication level for this (4%, 8%, 15%, 7%, 5%).
    A fairly frequent depth effect is "Visual depth perception changes, so that near objects seem much nearer and far objects seem much further away" (32%, 19%, 29%, 11%, 5%), what might be called a magnification of visual depth. This is reported as occurring in the higher intoxication levels (1%, 14%, 25%, 17%, 6%).
    The visual depth magnification effect seems to be a long-term effect, persisting steadily over time, compared to an infrequent effect that might be termed a visual depth jiggle: "Objects or people may seem to get visually nearer or further as I look at them without their actually moving at all" (39%, 23%, 21%, 10%, 5%). Many users (46 percent) did not rate the intoxication level for this (2%, 9%, 17%, 19%, 7%), although it is generally perceived at higher levels. Experience with using marijuana modulates this effect, whether factored in terms of total use or frequency of use in the last six months. Both Moderate Total users and Weekly users need to be more intoxicated for this experience than Light or Heavy Total users in the one case (p <.05) or Occasional or Daily users in the other case (p <.01).
Note.—For guide to interpreting the "How Stoned" graph,
see note on Figure 6-1.

    All four of these intoxication effects on visual depth perception are compared in Figure 6-3. The illusion of depth in flat pictures and the general magnification of depth both occur more frequently than the world's appearing flat or the depth's changing even as the user looks (jiggling) (p < < <.001), and the jiggling of perceived depth requires a higher intoxication level (p <.02).



    Two common phenomena represent an increased centrality of vision, enhancement of the focused object at the expense of peripheral objects: "Things outside the center of my visual field, things in the periphery of my vision look different when I'm not looking directly at them than when I look directly at them. E.g., I might see a door as open when I'm not looking directly at it, but when I look directly at it, it is closed" (19%, 21%, 32%, 19%, 7%) and "My visual perception of the space around me is changed, so that what I'm looking at is very real and clear, but everything else I'm not focusing on visually seems further away or otherwise less real or clear" (23%, 15%, 27%, 19%, 13%). Both have a modal level of intoxication of Strongly (3%, 23%, 29%, 17%, 5% and 4%, 17%, 25%, 17%, 6%, respectively). Neither the frequency of occurrence nor level of intoxication distributions differ for these effects.
    Several background factors affect whether things in the periphery change. Younger users and Non-users of Psychedelics report this phenomenon as occurring more frequently (p <.05, p <.01, respectively) compared to Older users and Users of Psychedelics. Further, Users of Psychedelics are more variable in their ratings for this than Non-users (p <.05) and generally require higher levels of intoxication.
    With respect to increased centrality of vision, Daily and Weekly users must be more intoxicated than Occasional users (p <.05, overall).


Sensuality, Aliveness

    Another common phenomenon is "There is a sensual quality to vision, as if I were 'touching' the objects or people I am looking at" (22%, 16%, 31%, 19%, 9%), which occurs at higher levels of intoxication (5%, 14%, 23%, 25%, 5%). This is reported more frequently among the College-educated than among the Professionals (p <.05). This effect is also reported most frequently among the Heavy Total users (modal frequency category is Very Often/Usually), next most frequently by the Moderate Total users, and least frequently by the Light Total users (p <.01 for the Heavy-Moderate, p <.01 for the Heavy-Light comparison, Moderate-Light not differing significantly). Further, the Moderate and Light Total use groups report higher minimal levels of intoxication for this than the Heavy group (p <.05, overall).
    The final infrequent effect on perceiving the external world is "Everything I look at seems to vibrate or pulse, as if it had a life of its own" (23%, 31%, 29%, 8%, 7%), which occurs at the higher intoxication levels (1%, 5%, 15%, 23%, 19%). Users of Psychedelics report a higher level of intoxication (mode at Maximum) for this than Non-users (p <.05).




    A very characteristic phenomenon is enhanced visual imagery: "If I try to visualize something, form a visual image, I see it in my mind's eye more intensely, more sharply than when straight" (12%, 3%, 22%, 25%, 35%). This begins occurring in the low-middle ranges of intoxication (13%, 33%, 24%, 11%, 3%).
    A specific illustration of this is the common effect, "I have more imagery than usual while reading; images of the scenes I'm reading about just pop up vividly" (15%, 11%, 24%, 27%, 15%), which also occurs at the lower levels of intoxication (13%, 33%, 22%, 4%, 2%). The Weekly users have to be somewhat more intoxicated to experience this than the Occasional users (p <.05), with a suggestion that the Daily users do not have to be as intoxicated as the Weekly users (p < .10). While the general enhancement of visual imagery occurs more frequently than visual imagery accompanying reading (p <.01), the distribution of levels of intoxication does not differ significantly.
    A related phenomenon, described fully in Chapter 15, "When thinking about things while stoned, there are visual images that just automatically go along with thinking," a very common effect, which occurs at Moderate levels of intoxication.



    Two frequent phenomena stand midway between perceptual alteration of real phenomena and hallucination: "I see fringes of colored light around objects (not people), what people have called the 'aura'" (46%, 21%, 20%, 8%, 1%), and "I see fringes of colored light around people (not objects), what people have called the 'aura"' (50%, 23%, 19%, 5%, 1%).[2] Many users (57 percent, 59 percent, respectively) did not rate the level of intoxication for this, but for those who did, it was generally rated in the highest ranges (1%, 4%, 15%, 10%, 13%, and 3%, 2%, 9%, 12%, 15%, respectively).
    Seeing an aura around objects is somewhat more common in the Younger group than in the Older group (p <.05); more common in Heavy Total users of marijuana than in Moderate (p <.05) and Light Total users (p <.05); more common in Users of Psychedelics than in Non-users (p <.05). Seeing auras around people is also more frequent in Users than in Non-users of Psychedelics (p <.001).



    Pure visual hallucination is an infrequent phenomenon: "With my eyes open, I can see things that aren't there, i.e., for which there is no real visual basis. E.g., if you look at stains on a wall and see a design, that's an illusion; you are altering something there. This question deals with seeing something when there's nothing there, such as seeing a pattern or object on a perfectly blank wall" (33%, 23%, 27%, 7%, 9%). Although many (45 percent) users did not rate intoxication level, when it does occur this is a high-level phenomenon (1%, 6%, 10%, 20%, 18%). It is reported more frequently in the Younger Group (p <.01), and more frequently in the Heavy and Moderate Total use groups compared to the Light Total use group (p < .05 overall).



    A number of users wrote in additional visual effects in the final part of the questionnaire.
    Three users mentioned stroboscopic effects on vision: (1) "Old-time movie effect, where people move in phases as in a movie running too slow" (Sometimes, Strongly); (2) "I see in frames like a movie, only slowed down" (Rarely, Strongly); and (3) "Vision distorted as if seeing world with big strobe light flickering overhead" (Sometimes, Maximum).
    "I see movement in things that I focus on, a matchbook cover with a geometrical design shifted like a light show movie; the more stoned, the bigger they are of movement" (Sometimes, Fairly).
    "I find a continuum which starts with things' being two-dimensional and progressing to deep three-dimensional. I find I can stop anywhere on it" (Usually, Maximum).
    "I can see the texture of the air in little swirling dots" (Usually, Just).
    "Things inanimate, like a pile of clothes, seem to come to life;" (Sometimes, Strongly).
    "Much more fun to watch color TV or newscasts" (Sometimes, Fairly).
    "Am able to see mythical, angel-like creatures, which seem to be personal spirits" (Rarely, Maximum).
    "Figure-ground shifts become more frequent and easier to control when stoned" (Sometimes, Strongly).
    "I get more, and more pronounced, afterimages" (Rarely, Strongly).
    "Aesthetic perception augmented re Cezzane [sic]: see interview with Allen Ginsberg, Paris Review #37" (no specification of frequency or levels).



    The grouping of visual phenomena by intoxication levels is presented in Figure 6-4 and is highly significant (p <<< .0005). At the lowest levels, vision may sharpen up, patterns may appear, and colors may be affected. Further up, visual imagery is enhanced, and vision may become more central with depth magnified. Between Strongly and Very Strongly intoxicated, a sensual quality is frequently added to vision, and the external visual world may become unstable, with blurring and jiggling in depth. As one goes higher, vision may pulse, faces may change, auras may appear around objects, and at the highest level the maximal alteration of the visual world may occur with hallucinations and auras around people.[3]

Just        Fairly    Strongly  Very

Type size code:
Flat quality to the world
colors get duller

Just        Fairly    Strongly  Very



    Table 6-1 summarizes the effects of background factors that have relatively linear effects. Imagery automatically accompanying reading and visual jiggle appear to have a curvilinear relationship to drug experience, occurring more frequently and at lower levels of intoxication with moderate experience than with little or much experience.
    In general, more drug experience goes with sensuality and unusual visual experiences, and with more intoxication required for the possibly undesirable effects of blurriness and pulsing of vision.

More Drug ExperienceMore frequent:
    Sensuality of vision
    Auras, objects
    Auras, people
    Face changes
More intoxicated for:
    Pulsing of vision
    Peripheral vision changes
    More centrality of vision
Less frequent:
    Peripheral vision changes
Less intoxicated for:
    Sensuality of vision
Older  Less frequent:
    Peripheral vision changes
    Auras, objects
More educated 
More intoxicated for:
    Colors duller
Less frequent:
    Patterns in ambiguity
    Sensuality of vision
Males  Less frequent:
MeditationMore frequent:
    Face changes
Therapy & Growth  Less frequent:
    New colors



    In general, the specific changes in visual perception brought about by marijuana intoxication may be seen as particular manifestations of a general change in what we might call the visual pattern-making process. It is common to assume that we passively "see" what is out there, that the qualities of the visual world are inherent in the physical properties of objects and space. Modern psychological investigations have made it clear that seeing is a very active and complex process in which we construct the visual world from the flux of visual sensations reaching us. That is, patterns, forms, objects, recognizable people, etc. exist in our minds as a construction from visual data. We are so used to doing this automatically that it seems as if the visual world were given. This active nature of visual perception is true of all sensory modalities.
    The patterns that are formed from visual data are organized into a degree of complexity and familiarity that is optimal for surviving in the world around us. Detecting a potential predator concealed in some bushes has survival value; seeing a potential predator in every ambiguous visual input is not conducive to survival of the organism. Thus we may conceive of some optimal level (actually a dynamic range)[4] of patternmaking activity, of organization of ambiguous (and not so ambiguous) visual data into meaningful percepts. Raise this level too high and we have illusion or hallucination. Lower this level too much and we have stupidity.
    Marijuana intoxication seems to raise the level a fair amount, more so with increasing levels of intoxication. Thus patterns form from ambiguous material, contours are sharpened, central visual phenomena are enhanced at the expense of peripheral phenomena, depth is magnified and more subtle shades of color are perceived. With eyes closed, visual imagery is enhanced.
    Such a raising of level of the patterning mechanism is a two-edged sword. On the one hand, it may genuinely result in perceiving useful patterns and meanings that would have been overlooked. On the other hand, meaning may be falsely attributed to phenomena that have no such meaning. Many users seem to be aware of this combined advantage-disadvantage of marijuana intoxication and to compensate for it by requiring more data than usual before making a judgment or carrying out a consequent action. Others naively accept everything seen while intoxicated as true. This same dual aspect of raising the level of patternmaking activity applies, of course, to all sense modalities and cognitive processes.
    Whether the proportion of naiveté and sophistication is any different from that of ordinary people in everyday life is a moot question.


    1. For all items, frequency of occurrence data is always presented in the order Never, Rarely, Sometimes, Very Often, Usually, and intoxication level data in the order Just, Fairly, Strongly, Very Strongly, Maximum. These will not always add up to 100 percent because of variable numbers of respondents' skipping various questions and/or rounding errors. (back)
    2. Readers interested in this rather exotic effect may see Ellison (1962) and Kilner (1965). Most of the writing on this subject is mystical, but the above references do attempt some objective treatment of the phenomenon. (back)
    3. In general, intoxication effects that are two levels or more apart in this type Of graphical plot will be different enough to reach statistical significance. (back)
    4. The "optimal" level is quite situation-specific; depth jiggle, for example, may be quite amusing and enjoyable during a relaxed evening at home (safe conditions) but might be a pronounced disadvantage while working at some crucial task that required very accurate depth perception. (back)

Chapter 7

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