HALF BRAIN ROLE REVERSALS
The analytical, sequential, logical thinking of the left hemisphere is often said to describe the science-based cultures of the West, while the intuitive, spatial, relational mode of the right hemisphere is said to be characteristic of Eastern cultures. Having noted the deficiencies when either half of the brain is separated from the other, we might ask: Could so-called right hemisphere intuition play any part in analytical thought? And is so-called left hemisphere logic at all relevant to the intuitive mode? In other words, is there a meaningful relationship between the two halves of the brain that we can use to explain how we think, feel, and act as we move through our lives?
To explore these and other questions, let's look at our list of adjectives in light of the research findings on how the hemispheres work in normal people and in brain-damaged and split-brain patients. For example, take the set differential-existential. Differential means making distinctions among individuals or classes, and existential means of, relating to, or affirming existence. The research yields some interesting findings about these abilities. For example, in Levy's block-feeling test with the split-brain patients, the left hemisphere-right hand could not distinguish by vision which block was felt out of sight. In differentiating faces, the left hemisphere was decidedly inferior to the right in her tests unless it knew what to look for ahead of time. In other words, the left hemisphere distinguished faces by comparing the in terms of sameness to a preconceived characteristic.
In Brenda Milner's bent wire test, the results were similar. The left hemisphere-right hand feeling the wires out of sight could not distinguish one from the other in free vision. The same is true for music. The left hemisphere cannot tell the difference between the pitch of one note and another. In Deglin's research with one hemisphere at a time, the left-hemisphere person was unable to distinguish between a man's and a woman's voices or the tone of voice in either person. Finally the emotional reaction to various situations remains characteristically the same among patients with right hemisphere damage.
The right hemisphere in all these tests could make distinctions easily. But as far as the vocal affirmation of these differences, all it could do is mutely point. It has little or no ability to communicate in the "symbolic coin" by which humans articulate ideas. It can imitate or duplicate sounds it hears and copy simple figures put before it. If it cannot directly relate in terms it has seen or heard, it cannot affirm existence.
What emerges from this dichotomy, then, is the irony that the ability of differentiating attributed to the left hemisphere is what the right hemisphere seems to do best, while the quality of affirming existence by symbolic action is the job of the left hemisphere. In other words, when the hemispheres are separated or reviewed individually, each seems to take on the qualities attributed not to itself, but to its mirror-image companion.
Let's continue this investigation of the qualities associated with the hemispheres. Similar dichotomies of the concept of time are discrete-continuous, lineal-nonlineal, historical-timeless, and successive-simultaneous. The first of each of these pairs implies one thing following another or one item at a time sequentially. The second half of each pair implies wholeness and no sense of sequence.
The left hemisphere is the one that is associated with time and sequence in this paradigm, while the right has no awareness of sequence and time. Roger Sperry, in describing the split-brain patients, noted that their conversation tended to be restricted to the immediate and that they tended to repeat themselves unknowingly. To the observer it appears these patients live only in the present moment with little indication of an awareness of the passage of time. Stuart Dimond pointed this out as well in his comment on how split-brain patients were still saying the same things they were saying two years before in the same way without any memory of having met him before. To quote Dimond directly: "...yet time stands still not only because of the poor memory but rather because the same thoughts, the same mental content, are still circulating in much the same way."22 There seems to be no sense of history or the passage of time in the isolated left hemisphere.
In the one-hemisphere person studies, the left hemisphere knew the calendar date and time but could not tell the time of day or season by looking out the window. Without a connection to season or, in general, various changes in the environment, time has no meaning. It's like being snow blind in a blizzard, all locations are the same. The studies of patients with damaged brains reveal this same situation with the regular citing of the repetition of ideas and little perseverance on tasks through time. Howard Gardner tells of asking a patient with a right hemisphere lesion how long he had been "here" (meaning the length of time in the hospital), and the patient responded, "About five or ten minutes, Doctor, I wasn't looking when I came in" (meaning in the examination room).23
The right hemisphere conversely, does seem to have a feel for the passage of time but without a sense of what time is. For example, the right-hemisphere person does know the season by looking out the window though calendar date is beyond their comprehension. Other studies show that the right hemisphere responds appropriately to changing situations through time. It has a sense of history and the succession of events, while the left hemisphere's world seems to take on a timelessness and sameness through time. We see that all the qualities imputed in terms of time to one or the other hemispheres seem lost to it when one is separated from the other. Indeed, each one seems to be processing in the exact opposite of the descriptive terms assigned to it.
Another classification of the hemispheres is abstract-concrete or symbolic-concrete. Here it is the left hemisphere that deals with abstraction and the manipulation of symbols in ways that are not tied to concrete reality. The right hemisphere, conversely, can only deal with what is really there. What does our research show in this regard? Language is the human symbol system that facilitates our communication with one another. Although patients with disconnected left hemispheres use words with ease, the researchers continue to remark on the literalness of their interpretation of words. Words, for these individuals, evoke only the images that reflect their exact arbitrary meanings. The context of communication that usually gives meaning to our words is totally lost on them. Klaus Hoppe is a Los Angeles psychiatrist who has examined the dreams, fantasies, and use of symbols of 12 commissurotomy patients. Dreams and fantasies are usually highly symbolic of the inner self. The use of symbols, such as words, reflects one's ability to see and manipulate (at least mentally) one's environment. Hoppe reports of his impressions of the speaking left hemispheres of these patients:
[The examination] suggests that patients after commissurotomy reveal a paucity of dreams, fantasies, and symbols. Their dreams lack the characteristics of dream work; their fantasies are unimaginative, utilitarian, and tied to reality; their symbolization is concretistic, discursive, and rigid.24In other words, their symbols are directly tied to reality, that is, their direct assigned meaning, without seeming ability to conceive of an alternative meaning outside this. This observation is backed up by other research. The speech of Deglin's left hemisphere became flat and atonal, and words were used only in their literal sense and understood only in terms of their concrete meanings. And the same was true of Gardner and his colleagues' research with brain-damaged patients.
The report cited earlier on the behavior of several hemispherectomy patients typically states that individuals without a right brain had a paucity of associations with little originality, and their thinking was characterized by stereotypes. And Howard Gardner notes that patients with intact left hemispheres seem only aware of the denotative, literal meanings words, with no comprehension of voice tone or the connotative (contextual) nature of words.
The right hemisphere has little ability to use propositional speech and has great trouble with abstract words, that is, words that stand for classes of items rather than specific items. However, as Joseph Bogen points out in a frequently quoted article, the person with an intact right hemisphere "often uses descriptive phrases, similes, and metaphorical expressions in an appropriate manner."25 In most communication among human beings, it is the connotative, metaphorical context of the words used that gives meaning. For example, fables—teaching stories—are never meant to be taken literally. Yet that is the only way the left hemisphere can understand them. At the same time, we saw in the Gardner research how the right hemisphere does properly understand metaphorical speech.
So the same pattern begins to emerge here. The person with only a functioning left hemisphere insists on the literal meaning of his words as if the sounds uttered in saying the words are an inherent property of the items to which they refer. It is as if the personal value of a possession were tied only to its price in dollars. These persons find themselves only able to deal with organized reality as they are able to name it. They don't comprehend items without names they already know.
Conversely, the right hemisphere understands the metaphorical nature of utterances. The essence of poetry and other literary expression is metaphor, one image standing for another in a given context. In other words, it is concrete images used as symbols, and it is these kinds of symbols that the right hemisphere understands. The situation with disconnected hemispheres again becomes one in which their roles are exchanged. In this the left is more properly characterized as concrete and the right as symbolic.
Let's look at one final pair of adjectives to see how they hold up: Objective for the left hemisphere and subjective for the right. According to Webster's New Collegiate dictionary, "objective" means emphasizing or expressing the nature of reality as it is apart from personal feelings, while it defines "subjective" as (1) characteristic of or belonging to reality as perceived rather than as independent of mind or (2) being experience or knowledge conditioned by personal characteristics or states. We can think of objective, then, as seeing something for what it is, while subjective means seeing something in terms of certain qualities assigned to it by the perceiver.
Now recall Jerre Levy's chimeric images, where the split brain patient was asked to match the mixed figures according to functional or visual similarity. Recall also the similar task requested by Deglin of his left- and right-hemisphere persons. In Levy's test, the right hemisphere matched the image it saw in terms of visual similarity—in terms of what it looked like as an object—and not in terms of functional similarity. The same was true in Deglin's results. The right hemisphere matched numerals not as numerals, but as objects of visual similarity. In both tests, the left hemisphere matched them in terms of their functional similarity.
If we go back to our definitions of objective and subjective, we see that it is the right hemisphere's activity that more closely matches the definition of objective, seeing the images as objects, while the left hemisphere's action matches the definition of subjective, as it sees the images subjectively, that is, by function ascribed to them by human learning. Again, each half of the brain, when on its own, seems to perceive the world not in terms that have been used to describe it, but in terms used to describe the other half.
Continue to "Resolving the Role Reversals"
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