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MEMORY
One of the processes important in perception is the comparing of current input with similar past experience. When we see a friend, a memory image of his face is presented to our consciousness along with the sensation of his actual present appearance. This memory image (which can be called a schema) blends with the current sensation, so that the perception is a combination of the two. The relative strengths of each source of information probably vary from person to person. Some primarily perceive the memory image, with the sensory input serving as confirmation of the identification. For others, the memory image may be so weak that reorientation and identification is continually necessary. Though the construction and recall of this image is not clearly understood, it must be partially constructed from previous experience of the stimulus (including verbal knowledge) up to a point where the person knows all he needs to know for purposes of his response. After this, encounters with the stimulus do not add to the memory image appreciably; further discrimination is unnecessary and the image stabilizes. (Of course, the person may continue to make discriminations. One of the valued behaviors in science is to make perceptual discriminations for which we have no functional need, assuming that such information is valuable per se or may be valuable later.)
Most persons rely principally on memory images in perception unless there are evident differences in the immediate situation, and their responses are keyed to the memory image. Consequently we do not respond only to immediate experience. We identify current experience according to past experience and then respond on the basis of past experience, modified by whatever differences we perceive to be significant in the current information. Our actions originate from past experience, they are connected to the structures built up in our memories, and these memories are elicited by the immediate stimulus. In unfamiliar settings, no memory image is available. Then we must deliberately and consciously act, randomly act, follow instructions or models, or act according to the most similar memory image. Any situation is a combination of elements, and may call for complex combinations of memories and response patterns, some new, some familiar.
Marijuana has two effects on this process. The first is to reduce the general automatic availability of memory images; the second is to increase the strength of memories when they are relevant to central needs. We have already discussed the general reduction in strength of memories in response to current experience, which is principally in the automatic recall of memory schema. The strength or visibility of the mental image is reduced, with a resulting increase in the brightness of the data themselves (there being nothing else to look at). This explains also why experiences seem new: they are observed without the feeling of familiarity caused by memory images. For most persons in straight consciousness it is likely that sensation is checked against a memory image (at a preconscious level) and what is seen from the current stimulus is what is necessary to fulfill the criteria for identification, based on the memory schema. The relevant elements, the criteria, are affected by the goals or functions which are important to the person. We do not perceive dust on a typewriter when we look for something to type on. When we look for a friend in a crowd we do not look at his face, we identify it. Similarly, in conversation and daily life we generally know what we are seeing, so perception is more identification than observation. However, when fewer memory images are available, as when high, one must respond to the sense data as unfamiliar material. This may cause anxiety, depending on the individual and the environment, or it may result in pleasure at the enhancement or challenge of current perception. It may also increase the potential responses, since there is less pressure for a learned habitual response, which would normally inhibit other responses.
(This may, incidentally, suggest an explanation for the jamais vu sensation, in which there is the feeling that a normally familiar situation is totally unfamiliar. Several experiences of jamais vu reported to me seem to have occurred when there are unfamiliar emotional elements present, as though the usual memory schema and their associated responses were not available.)
At the same time, some memory images may be strengthened if they are emotionally salient. A person having paranoid fears, for example, may find his imagery increased in strength. One person reports that once when high he observed a friend sitting to one side of him staring directly at him. He turned to face his friend and found him looking in another direction, his face turned partially away from him. Apparently a fear activated the image of a full staring face, which was superimposed on the profile of the other person. It may be that psychotic or schizophrenic perceptual projections are partially caused by increased internal imagery. Under marijuana, at least, emotional force may activate internal imagery which is used to search for, identify, or interpret incoming stimuli.
So also if the person deliberately attempts to recall past experiences there will often be increased recall, either of events in great detail or Hashes of experiences. This is particularly true if there is salient emotional content. Recall which appears to be eidetic may occur under marijuana, and images which are like playbacks of the original perceptual experience may become accessible at will to conscious attention. If the conscious attention is allowed to unfocus, so that only monitoring is going on, almost instantaneous images can be obtained of visual and sometimes auditory or tactile stimuli. The image must be seen when it occurs; if there is an attempt to hold it in consciousness a mental composite image takes its place. It is possible that what occurs is an activation of the actual memory record, selected from the stream of consciousness which is recorded in the brain.(7) Only one flash comes at a time. This ability, incidentally, has been transferred to straight, non-high control after it has been observed under marijuana. The essential feature seems to be in allowing the conscious attention not to try to hold on to the image when it appears. One must learn to see rather than look.
Another type of memory which is strengthened is that for emotion-laden events. Strong emotional responses, such as grief, fear, guilt, etc., often arise under marijuana. These are responses to remembered events, responses which might normally be suppressed. Usually the person's sense of identity is functioning, so he can either accept the emotion and be a part of it, which is usually therapeutic, or reject it, which may produce dissonance and anxiety. "Bad trips" are sometimes caused by emotions or pressures which threaten the person's self concept or his sense of control. While suppression processes are usually not too effective as defenses, distraction is, because of the mobile flow of attention under marijuana. For this reason, movement such as dancing, running, exercise, showers, etc., will usually change the emotional tone.
One other effect on memory should be noted. Normally we have a short-term recall process which holds memories in access for about 20 minutes, and then a long-term storage, which is permanent. In the high state, short-term memory becomes shorter, and in very high states the sequence of thoughts is not remembered past one or two transitions. The sequence can sometimes be recalled with an effort, or reconstructed, but there is no automatic remembering as there is normally. On the other hand, after the high, events within it can be remembered, indicating that at least some of the experiences are being filed in long-term memory.
Partly due to the reduction in strength of memory there is less intellectual control over the stream of consciousness. Memory seems to be needed to maintain concepts or goals under which to manipulate thoughts. Another cause of the reduced control is the lowered inhibition processes, which are used in thinking to filter irrelevant material and keep it from cluttering the conscious attention. Logical ideas and connections may also be enforced by such inhibitions; these would be loosened by the decrease in association strength. |
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