|
|
DAMAGED BRAINS
Studies of people with brain damage are yet another way to learn about brain processes. Especially revealing are the descriptions of people who have, for one reason or another, had one of their cerebral hemispheres removed in an operation called a hemispherectomy. One study reported on several patients with such operations. Of those with a right hemispherectomy, the following quotes are excerpted from a research report as examples of behavior:
...was occasionally maudlin and abnormally elated. She wrote a good letter but was inclined to repeat herself without being aware of it. (31 year old female)
There was a paucity of associations, stereotypy, and some perseveration of ideas. Tests indicated a person of average intelligence but with a superficial mentation with little originality, lacking in any deep introversive processes and in motivation, and given to sudden and illogical mood swings and easy petulance. (35 year old male)
He is emotionally unstable, inconsistent, and lacking in perseverance. Careless in his appearance. Not greatly disturbed by his physical handicap. (27 year old male)
On the Rorschach he gave a minimum number of responds, fatigued easily, displayed a narrow range of associations and little originality or imagination, indicating a dull intellectual functioning, and no ability for deep thinking or for adequate self evaluation. (45 year old male)13
In other words, these researchers found that the absence of the right hemisphere adversely affects sticking to tasks over time as well as imagination and original thinking and appropriate emotional responses in given situations. In another study, the same scientifically descriptive phrases were used to characterize the post-operative condition of a 54 year-old man who had a right hemispherectomy: "...paucity of associations, perseveration and stereotypy, concreteness of thinking, and delayed reaction times."14
We may compare these observations with the earlier cited findings of Sperry and Dimond with regard to talkativeness, repetition (perseveration), and the apparently inappropriate emotional response of the disconnected speaking hemisphere in the split-brain patients. But let's look at some more of the evidence.
Peggy Gott, a colleague of Roger Sperry's at Cal Tech, has examined various hemispherectomy patients. She reported on one in detail—a 12 year old girl who had the left half of her brain removed at age 10 because of a malignant tumor. Because of her youth, the girl's ability to create expressive speech was not wholly destroyed by the operation; however, as a rule she was limited to single words or short phrases. She had retained, though, her ability to sing and was good at it. She could also count up to 30 or 40 and could write numbers up to 10. However, if a number was pointed to, she could only name it by starting at one and counting until she reached the desired number. She did not have the ability to arbitrarily assign a verbal name to a visual symbol. Nor could she recognize letters or words, though pictures were not a problem. Finally, Professor Gott notes in her paper, "Additional observations from the present study indicate that personality characteristics such as humor, boredom, love, and frustration are readily exhibited by the right hemisphere in a pattern reported by the parents to be substantially the same as before the surgery."15
With this case, we see severe restrictions of the ability to use symbols in a purposeful way though the child's emotional tone and personality were seemingly unaffected by the loss of her left brain, which was not true in the right brain-loss cases just described.
Another widely cited paper notes the abilities of a 47 year old man after left hemispherectomy. Immediately following the operation, the patient, E.C., could not speak but could utter short emotional phrases such as "Goddamit!" At five months after the operation, E.C. suddenly burst into song, as it were, with recall of old familiar tunes such as "America" and "Home on the Range." Though he was unable to write, he was able to correctly select the names of items on something called the Peabody Picture Vocabulary Test from groups of words read for each item but could not necessarily name these items himself. He as also able to pick out colors from a display as they were called out by the examiner. He retained some simple arithmetic ability but was unable to deal with any complex calculations. As with the 12 year old, his affective reactions and general behavior were appropriate in all situations, and his wife reported no noticeable change in his emotional response or personality from before the operation.
Howard Gardner of the Boston Veteran's Administration Hospital and Harvard University has long been interested in the connection between behavior and right and left hemisphere damage. With his colleagues he has undertaken several innovative experiments to find out what happens when, by stroke or other injury to half the brain, one or the other of the hemispheres is left to deal with the world by itself.
In one study he and his colleague Ellen Winner decided to look at the comprehension of metaphor by the two hemispheres. To understand a metaphor, a person must go beyond the literal meaning of the phrase and understand it as a way of describing something else. For example, it is common to use physically descriptive terms to describe psychological traits such as a hard heart or a dry wit. Literal understanding of such phrases would essentially block real communication between persons.
Their test consisted of reading a sentence with a metaphor such as "a heavy heart can make a difference," and then displaying four pictures that illustrate the phrase in different ways: (a) metaphorical (a person crying), (b) literal (a person carrying a large red heart), (c) one whose main point was the adjective (a 500 pound heart-shaped weight), and (d) one whose main point was the noun (a red heart). Upon hearing the sentence, the patients were to choose the picture which best illustrated the phrase in the sentence. Following this, Winner and Gardner asked the patients to explain what it means to say, for example, a heavy heart.
What they found was that patients with right hemisphere damage and an intact left hemisphere were more likely to choose the literal picture as a first or second choice of what the phrase meant. Even when they correctly chose the metaphorical picture, they found nothing strange about the other pictures and did not understand their absurdity in light of the phrase's metaphorical nature. Those patients with intact right hemispheres but damaged left ones usually chose the metaphorical picture and rejected the literal ones as funny and absurd.
When they asked the patients to explain the phrase, there was an interesting turnaround. Whereas the patients with functioning right hemispheres correctly identified the metaphorical picture, they could not explain the phrase except by repetition of the words themselves as though to them the literal meaning of a heavy heart was a sad person. Those patients with right hemisphere damage, though they often chose the literal picture, could easily explain the phrase correctly; for example, "He's got many troubles." Here these patients know the linguistic dictionary meaning of a phrase (which has come to be "sad person", but outside of the linguistic mode, they could often only visualize the phrase literally.
Another study undertaken by Gardner, Wendy Wapner, and Suzanne Hamby at the Boston Veteran's Hospital is even more revealing of the processing differences of the two hemispheres. What they explored was the ability of patients with right hemisphere damage, and with intact left (verbal) hemispheres to understand stories, retell them properly, to answer questions about them, to grasp the moral of fable-like stories, and to understand jokes. What they found was often great impairment of these patients' capacities to properly understand these "linguistic entities." Or perhaps a better way to state their results is they found out still more about how the solitary left hemisphere deals with the world.
When these individuals were asked to retell stories they had just heard, they often embellished them with confabulation of details along with improper understanding of the emotional or spatial aspects that were important to knowing what the story was all about. These patients frequently did not comprehend the moral of fables that were always understood by a control group of normal persons tested to provide a context for this research.
As an example of left hemisphere performance in these activities, one patient, in an embellishment of a story about a robber who had stolen all of a grocer's goods (instead of money), tells the researcher that the robber while escaping "tripped on the sidewalk and broke all the eggs." That incidents such as this were not in the stories did not seem to bother these patients at all. They justified the inclusion of such changes in the retelling by saying they improve the sense of the story to them. In general, they are not aware that the stories they heard and retold are very different from one another. In a fable called The Silver Hammer, the moral was a play on the Golden Rule. This was often missed by these patients as they came up with morals like "keep clear" or "take care of your tools."
In one test with jokes, humorous stories were presented up to the punch line, and the patients had to choose from four choices the appropriately funny ending. Their choices were often wrong in light of the stories and, in fact, there was frequent selection of an ending that was a non-sequitur, which they would justify with remarks like jokes are supposed to have surprise endings. For example, in a joke about a parade, one patient chose the non-sequitur "I wonder what's for dinner tonight?" as the punch line. When asked to explain why this was funny, the patient responded, "Why are they worrying about dinner if they're worrying about a parade?" Instead of getting the logic of the jokes and therefore choosing the right punch lines, patients were reduced to selecting something that had as its sole justification the fact that it was a surprise. This rationalization is consistent with what happens in a joke, but the selection was inappropriate for this joke.
What Gardner, Wapner, and Hamby concluded was that patients with right hemisphere damage can always grasp the literal linguistic message of stories, but they do not understand the implications of these messages, that is, the reasons for their being uttered in the first place. And while it was obvious that the patients were missing the point of the stories, none of them ever said, "I don't know" in responding to an open-ended question. They, that is these persons with only the left half of their brains in good working condition, could always confabulate some sort of answer to these questions. The researchers state:
Confronted with complex linguistic entities, such patients exhibit clear and recurring difficulties to conceptualize the unit as a whole, to appreciate its purpose and its own form, and to integrate specific elements appropriately within these forms. Correlatively, many of the patients seem insensitive to the context in which these linguistic entities are produced and utilized. Finally, they seem unable to honor the world of the fictive, the imaginary, the humorous—they seem uncertain how to relate to these entities and, in fact, sometimes appear as if they are unaware altogether of their existence as separate and specifiable forms of language.16
In other words, beyond the literal meaning of the words, these patients have little comprehension of verbal communication. They miss almost entirely the context in which their own or the words of others are framed. And it is almost always this context which gives meaning to what we say.
Howard Gardner has written an excellent account of the behavioral effects of brain damage in his book The Shattered Mind. He describes one of the most common occurrences with a stroke in the right hemisphere: left side neglect. In this situation, the affected side ignores the entire left side of space. Persons with this condition shave only the right side of their faces, eat food only on the right side of the plate, and cannot dress themselves properly, putting shirts on upside down or forgetting to put a leg, usually the left, into their trousers. In some cases, they actually deny the left half of their bodies are part of them. They often joke about this, with one patient saying of his left hand, for example, "Keep you eye on it, and you'll see it jump."17 They have a general tendency to deny anything is wrong and to create patently false (to you and me) explanations for such difficulties.
These patients can recognize objects that have names they previously knew. However, the functioning left hemisphere does not comprehend objects with unusual shapes or textures that do not have previously known names, and the patients generally ignore such objects. Depending on the nature of the right hemisphere damage, some patients will not recognize faces, even their own. Yet the characteristic lack of concern continues to be evident despite these problems. Gardner mentions one patient who explained why he was in this hospital this way: "The roof fell in on me...this is no Playboy Club you know...the warden calls me down for dinner."18 Though the nature of emotional response to their situation may vary from patient to patient, Gardner points out that whatever the emotional "set" may be, "that set is maintained more or less consistently, however inappropriate it may be in various circumstances."19 And while these patients may be aware of the denotational (literal) meaning of words, they are not aware of the nuances and connotations and cannot comprehend tone of voice or the general context of a conversation. So without a functioning right hemisphere, patients become like islands unto themselves. They do not comprehend their own disabilities and are not able to grasp the emotional context of their interactions with others.
But what of the person with left hemisphere damage? The obvious deficit is an aphasia (loss of speech ability), which can be characterized by a variety of problems having to do with grammar, syntax, semantics, or all three. However, there is no neglect of the right side of the body. The patients retain a grasp on spatial relations, can recognize faces (though names may be lost), and can recognize and respond appropriately in emotional situations. There is, then, in these patients, the correct perception of reality but with little or no ability to do anything about it, as they can no longer sequence and communicate their thoughts using the sounds we call words and language. Gardner summarizes:
The individual without his left hemisphere is certainly lost, for he cannot communicate with his world in the symbolic coin it favors. But in a different way, the individual with his minor hemisphere [right] has also been abandoned, for he can no longer find his way about and cannot make use of the various psycholinguistic cues that modulate conversation and dominate nonverbal interaction.20
Of course, those of us with normal brains can do both of these things with ease at the same time.
Continue to "Right and Left Reality"
Return to first page
|