When Two Brains Are Not Better than One


Brains

The myth of “right brain” vs. “left brain” thinking and learning styles has enjoyed much staying power in pedagogical discourse. The severing of our cognitive and conscious selves can be traced back to Roger Sperry, the 1981 Nobel Prize winner who demonstrated distinct differences in the cognitive functions of the cerebral hemispheres by studying “split brain” patients (Lilienfeld & Arkowitz, 2008; Hermann, 1998). The idea was further popularized by Stanford Psychologist Robert Ornstein, who argued that Western society is too “left brained” (Lilienfeld & Arkowitz, 2008). Certainly, dominant as well as specialized functions of the cerebral hemispheres have been identified. For example, the right hemisphere is specialized for vision and the left for language. However, neuroscientists now agree that it is the functional interconnectivity and parallel processing of brain structures that makes us who we are (Restak,2001; Geake, 2007; Mercado, 2008; Ratey,2001; Hermann, 1998). Hermann (1998) states:

“If the right hemisphere were somehow disconnected from the left and confined to its own specialized thinking modes, it might be relegated to “soft” fantasy solutions, pipe dreams, or weird ideas that would be difficult if not impossible to fully implement in the real world”

Language, long understood to reside exclusively in the left hemisphere, provides an interesting foil for considering the linguistic mediation and distinct contribution of the right hemisphere processes to our ability to decode, order, comprehend, generate, and resolve ambiguity.

Phonology and Orthography

George Bernard Shaw once noted that we might as well spell the word fish “ghoti”:
• GH /f/ as in laugh
• O /i/ as in women                            
• TI /sh/ as in nation               

In English, the spelling ‘fish’ is only used in words that can be reduced to the base morpheme of fish (eg. fisheries) and not benefishal.

Phonology is the sound system of our language. English phonology includes 44 phonemes that map onto over 250 graphemes. We have to understand that “wax” has four phonemes and that “ow” can produce two sound combinations, depending on its placement within a word and/or a sentence (The actor took a bow. The gift was tied with a bow.) When words are orthographically (bough/ trough) similar and/ or phonologically similar (rain/ reign) processing requires bilateral activation of the hemispheres (Chiarello & Hasbrook, 1999). There is also evidence that the subtle analysis required in differentiating voiced and unvoiced pairs (eg. b/p) involves the right hemisphere, while phonetic discriminations based on place (tongue placement, lip placement, airflow) are left-hemisphere dominant (Chabris & Kosslyn, 1998). Both must work in concert in order for us to track, discriminate, and isolate phonetic structure.

Prosody

Prosody plays an essential role in our ability to comprehend both conversation and text. Prosodic elements include the linguistic (parsing, emphasis) and affective components (tone). Consider the example below:

My Dear Pat,
The dinner we shared the other night — it was absolutely lovely! Not in my wildest dreams could I ever imagine anyone as perfect as you are. Could you — if only for a moment – think of our being together forever? What a cruel joke to have you come into my life only to leave again; it would be heaven denied. The possibility of seeing you again makes me giddy with joy. I face the time we are apart with great sadness.
John
P.S.: I would like to tell you that I love you. I can’t stop thinking that you are one of the prettiest women on earth.

Or this:                                                                  

My Dear,
Pat the dinner we shared the other night. It was absolutely lovely — not! In my wildest dreams, could I ever imagine anyone? As perfect as you are, could you — if only for a moment — think? Of our being together forever: what a cruel joke! To have you come into my life only to leave again: it would be heaven! Denied the possibility of seeing you again makes me giddy. With joy I face the time we are apart.
With great “sadness,”
John
P.S.: I would like to tell you that I love you. I can’t. Stop thinking that you are one of the prettiest women on earth (Ledderer, R.; Shore, J. Comma Sense)

If you were Pat, you would understand that our brains have to attend not only to what (semantics) is said, but how (intonation) it is said (Van Rijn, et. al., 2005; Wartenburger, et. al, 2007). Translation of prosodic elements requires simultaneous contribution from both hemispheres (Van Rijn, et. al., 2005; Azan, 2005; Wartenburger, et. al, 2007). In a virtual lesion study comparing hemispheric contributions to the processing of affective vs. linguistic prosody, Van Rijn, et. al (2005) found right hemisphere activation in a sentence listening task requiring subjects to identify whether a the voice of the speaker was happy, angry, sad, or fearful. Specifically, the right hemisphere shows particular activation in the identification of fear and sadness. In a tone-neutral trial where prosodic elements were presented semantically, there was left activation. Ayan (2005) compared hemispheric contribution to the processing of prosody in pictures, words, and intonation of sentences. The intonation condition required bilateral activation.

Syntax

“If I had a world of my own, everything would be nonsense. Nothing would be what it is, because everything would be what it isn’t. And contrary wise, what is, it wouldn’t be. And what it wouldn’t be, it would. You see?” –Alice

Syntax is the grammatic rule system of our language. Although syntax is thought to be specialized in the left hemisphere, patients with right hemisphere damage do have difficulty with tracking and manipulating complex sentence structure (Beeman & Chiarello, 1998; Prat, et al, 2007). In fact, in an fMRI study Prat, et. al determined that as sentence complexity increases, there is right hemisphere activation in regions opposite to the specialized left hemisphere regions. Right hemisphere activation may be providing scaffolding to “hold” contextual elements in mind while the left hemisphere tracks place and time. For example, Kuperberg et al. (2005) determined that when subjects are presented with syntactic violations Broca’s area is not activated. There is also evidence that the right hemisphere is sensitive to number agreement (Beeman & Chiarello, 1998).

Morphology

I never heard of ‘uglification’”, Alice ventured to say. “What is it?”
The Gryphon lifted up both its paws in surprise. “Never head of uglifying!” it exclaimed. “You know what to beautify is, I suppose?”
“Yes”, said Alice doubtfully: “It means to make anything prettier.”
“Well, then,” the Gryphon went on, “if you don’t know what to uglify is, you are a simpleton.”

Morphemes are the basic meaning-carrying elements in our language. A single word may be constructed of one or several morphemes, as in “uglification”. Some root morphemes are words by themselves, such as “Gryphon”. Others are prefixes such as –un, -pre, or –in; or suffixes such as –ly. There are grammatical rules for the combination and manipulation of morphemes as there are for words. Marangola, et. al (2003) reported on two right-hemisphere lesion patients who had difficulty with substitutions of word endings. When morphological complexity is manipulated, there is significant right hemisphere involvement (Zahar & Ibrahim, 2007). Again, the right hemisphere is called to action when complex manipulations within words or between words require tracking and integration of less specifically related, ambiguous, or context-bound elements.

Homonyms

“How is bread made?”
“I know that!” Alice cried eagerly. “You take the flour- “
“Where do you pick the flower?” the White Queen asked, “In a   garden, or the hedges?”
“Well, it isn’t picked at all, Alice explained; its ground-“
“How many acres of ground?” said the White Queen.

Homonyms and homophones create ambiguity, too. For example, in the sentence: How much can a bare bear bear? (Cleary, 2007), we need to be able to determine what the sentence is about (a bear), the action of the sentence (to bear it), and the modifier for bear (without clothing). The right hemisphere plays a role in determining the contextual cues needed to determine where Alice got her flour and what kind of flower it was (Tompkins, et al 2008). There is also evidence that metaphorical language requires direct participation of the right hemisphere (Tompkins, et. al 2008; Pobric, et. al, 2008; Krouse, 2008; Krause, 2008).

Semantics

…”and even…the patriotic archbishop of Canterbury found it adviseable-“
“Found what?” said the Duck.
“Found it,” the mouse replied, rather crossly; Of course you know what ‘it’ means.”
“I know what ‘it’ means well enough, when I find a thing ,” said the Duck; “It’s generally a frog or a worm. The question is, what did the archbishop find?”

The Merriam-Webster online dictionary contains 50 definitions for the word ‘run’. In order to understand whether we have run out of something, run amok, run the dishwasher, or run down the street, we need to be able to generate hypotheses from the syntax and contextual phrasing of the sentence and or paragraph we are hearing or reading. Semantics also involves understanding of figurative language, implicit messages, sarcasm, and humor. In other words, it is the integration of lexical, pragmatic, and syntactic information in order to make meaning from text or speech. When linguistic violations are used to determine right hemisphere contributions to the processing of lexical information in fMRI studies, there is evidence that the right hemisphere is activated, particularly in cases of unusual constructions, pragmatic anomalies, and weak/remote associations (Kuperberg, et al 2000; Yochim, et. al, 2005; Koivisto & Laine,2000;Abdullaev & Posner, 1997). Generating novel or unusual uses for objects also activates right hemisphere assistance (Yochim, et al, 2005). Further, it has been well documented that people with right hemisphere lesions tend to have difficulty with interpreting sarcasm (prosodic and affective elements), metaphor, figurative language, drawing inferences, multiple meanings (eg. “run”) and generally getting the “gist” of connected text (Beeman & Chiarello, 1998; Chabris & Kosslyn, Bowden & Beeman, 1998; Koivisto & Laine, 2000; Tompkins, et. al, 2008).

Generally, the right hemisphere handles ambiguity. The right hemisphere activates concurrently, casting a wide neural “net” (coarse activation) over all of the possible associations that could be made for a for a linguistic problem, while the left hemisphere focuses on the specific relationships and meanings that are established (fine activation).

If we were unable to integrate information regarding the affective components of language, ambiguous language, context, and lexical referencing we would be unable to comprehend. That is hardly a less-dominant role for the right hemisphere.

“I quite agree with you,” said the Duchess; “and the moral of that is– ‘Be what you would seem to be’– or, if you’d like it put more simply– ‘Never imagine yourself not to be otherwise than what it      might appear to others that what you were or might have been was not otherwise than what you had been would have appeared to them to be otherwise’.”
“I think I should understand that better,” Alice said very politely, “If I had written it down: but I can’t quite follow it as you
say it.”

References

Abdullaev, Y., Posner, M. (1997). Time course of activating brain areas in generating verbal associations. Psychological Science, 8(1), 56-59.

Ayan, S. (2005). Right brain may be wrong. Scientific American.

Beeman, M., Chiarello, C. (1998). Complementary right and left hemisphere language comprehension. Current Directions in Psychological Science, 7(1), 2-8.

Bowden, E., Beeman, M. (1998). Getting the right idea: semantic activation in the right hemisphere may help solve insight problems. Psychological Science, 9(6), 435-440.

Chiarello, C., Hasbrooke, R. (1999). Orthographic and phonological facilitation from unattended words: Evidence for bilateral processing. Laterality, 4(2), 97-125.

Geake, J. (2008). Neuromythologies in education. Educational Research, 50(2), 123-133.

Koivisto, M., Laine, M. (2000). Hemispheric asymmetries in activation and integration of categorical information. Laterality, 5(1), 1-21.

Krause, K. (2008). Mapping metaphor: This is your brain on figurative language. The humanist, http://www.thehumanist.org , 13-16.

Kuperberg, G. R., Bullmore, E. T., Brammer, M. J., Rabe-Hasketh, S., Wright, I. C., Lythgoe, D. J., Williams, S. C. R., David, A. S. (2000). Common and distinct neural substrates for pragmatic, semantic, and syntactic processing of spoken sentences: An fMRI study. Journal of Cognitive Neuroscience, 12(2), 321-341.

Lilienfeld, S., Arkowitz, H. (2008). Uncovering “brainscams”. Scientific American.

Marangolo, P., Incoccia, C., Pizzamiglio, L., Sabatini, U., Castriota-Scanderberg, A., Burani, C. (2003). The right hemisphere involvement in the processing of
Morphologically derived words. Journal of Cognitive Neuroscience, 15(3), 364-371.

Mercado, E. (2008). Neural and cognitive plasticity: From maps to minds. Psychological Bulletin, 134(1), 109-137.

Pobric, G., Mashal, M., Lavidor, M. (2008). The role of the right cerebral hemisphere in processing novel metaphoric expressions: A transcranial magnetic simulation study. Journal of Cognitive Neuroscience. 20(1), 170-181.

Prat, C., Keller, T., Just, M. (2007). Individual differences in sentence comprehension:  Functional magnetic resonance imaging investigation of syntactic and lexical processing demands. Journal of Cognitive Neuroscience. 19(12), 1950-1963.

Ratey, J. (2001). A user’s guide to the brain. New York, NY, Pantheon Books.

Restak, R. (2001). Mozart’s brain and the fighter pilot. Richard M. Restak, M.D.

Rijn, S., Aleman, A., Diessen, E., Berckmoes, C., Vingerhoetz, G., Kahn, R. (2004) What is said or how it is said makes a difference: The role of the right fronto-parietal operculum in emotional prosody as revealed by repetitive TMS. European Journal Of Neuroscience, 21, 3195-3200.

Tompkins, C., Fassbinder, W., Scharp, V., Meigh, K. (2008). Activation and maintenance of peripheral semantic features of unambiguous words after right hemisphere brain damage in adults. Aphasiology, 22(2), 119-138.

Tompkins, C., Scharp, V., Meigh, K., Fassbinder, W. (2008). Coarse coding and
Discourse comprehension in adults with right hemisphere brain damage.
Aphasiology, 22(2), 204-223.

Wartenburger, I., Steinbrink, J., Telkemeyer, S., Freidrich, M., Friederici, A.,
Obrig, H. (2007). The processing of prosody: Evidence of interhemispheric
Specialization at the age of four. NeuroImage, 34, 416-425.

Yochim, B., Kender, R., Abeare, C., Gustafson, A., Whitman, R. D. (2005). Semantic Activation within and across the cerebral hemispheres: What’s left isn’t right. Laterality, 10(2), 131-148.

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