Language and the Brain
Explore the complex development of language and how our brain has paved the way ...
Various species of animals often communicate, such as bees dancing, or whales using low-frequency sounds, but it’s only humans who have developed a highly formal, complex, and structured way to communicate, and its through the use of spoken words that this takes place.
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During an interview, David Boulton, a learning-activist and technologist, asked Terrance Deacon to name the distinguishing characteristic of what makes us human.
“I do think that the development of language is the single most distinguishing attribute,” said Deacon, a renowned professor of anthropological biology and linguistics at the University of California-Berkeley. Boulton interviewed Deacon for the article “The Co-evolution of Language and the Brain” that appeared on the “Children of the Code” website.
Words as symbols
But, Deacon went on to say, it’s not only speech itself that sets us apart from animals, it’s the symbolic system of words within the framework of our cognitive processes and “the ritual, the mythology…simply ways of doing things that are organized conventionally, symbolically – this is the hallmark of our species.”
By calling words symbols, Deacon means that the combination of letters humans call “words” only stand for or symbolize the persons, places, and things of our world. For example, the words baby, bebé, enfant, and ???? all mean “baby.” The sound of the word has nothing to do with its meaning, it’s just a sound that represents the word “baby” in English, Italian, French, and Japanese. The combination of letters or icons has come to represent something that all humankind defines as a newborn or person newly arrived in this world.
When someone says the word “baby,” an individual’s brain has the ability to visualize a human baby, with four limbs, a human face, and can define the sounds (auditory perceptions) and smells (olfactory perceptions) that babies emit. People can also describe non-perceptual information about human babies, such as they belong to the human species – not the animal species – that they aren’t dangerous, and that people don’t “eat” human babies.
This process of visualizing a baby, naming its parts, its smells and sounds, and its non-perceptual qualities seems rather simplistic to most individuals, especially fully functioning adults who don’t hesitate to recount these widely known and accepted details.
Yet scientists know that this process isn’t simplistic at all, that it involves multiple areas of the brain and numerous, complex cognitive processes. And when scientists try and explain cognitive functioning in terms of brain chemistry, molecular structure, and anatomy, the science becomes increasingly complex – and increasingly open for debate among a number of scientists with different orientations.
Syntax as a human construct
For example, in his book “Human, The Science Behind What Makes Us Unique,” Michael S. Gazzaniga talks about the uniqueness of the human language with its formalized syntax, or the grammatical rules that help individuals design sentences in a way that others comprehend. Syntax is not random, states Gazzaniga, but organized in a “hierarchical and recursive way.”
This means that language has repeated and ordered rules, definitions, and procedures for forming thoughts and expressing them.
Gazzaniga, one of the founders of the field of Cognitive Neuroscience, has spent the last 45 years studying the underlying neural frameworks and cognitive functioning of the brain. During the book’s discussion on language he poses the question: how did syntax develop? Is there a natural ability that comes with each infant, something intrinsic that allows the child to learn, usually by the age of 4, how to form and speak sentences that others understand? Because without syntax, or formally agreed upon rules for the usage of nouns, verbs, direct objects and other parts of language, sentences would come out as nonsense.
And that single question about syntax divides many scientists today. Many, such as the renowned MIT linguist Noam Chomsky, believe language is unique to the human species, meaning that the human species is born with an innate ability for both symbolic representation and syntax. He does not believe as some scientists in any “evolutionary development” of this ability.
The Psycholinguistic Approach
Psycholinguistics differs from cognitive neuropsychology and cognitive neuroscience. Psycholinguists study the structure of language in normal functioning adults rather than language deficits and dysfunction in patients with brain impairments.
Noam Chomsky, Ph.D., has been a professor of linguistics and foreign languages at the Massachusetts Institute of Technology (MIT) since 1955. He pioneered the field of psycholinguistics, beginning in the 1950s, establishing a new relationship between linguistics and psychology.
Other scientists, however, believe that symbolic language and its rules of syntax did evolve with the human species, and that natural selection came into play as in other biological traits and abilities.
This is a major theory but only one of many differing opinions among scientists studying language and the brain today. It’s also an example of the type of investigation that makes the study of brain and language one of the most dynamic today.
Professionals who study the brains of primates and other animals, comparing and extrapolating their findings to the brains of humans, typically work in the neurosciences. However, some cognitive neuroscientists such as Gazzaniga study both primates and humans. Their work centers on understanding how the brain’s chemistry and neuroanatomy actually facilitate the processes of symbolic representations, sentence syntax, and word comprehension. And they try and understand how language processing connects with other cognitive functions, such as memory and attention (see Attention).
Still others in the field of cognitive neuropsychology also study the human brain, but tend to focus their research and investigations on how brain pathology, dysfunction, and injury affect language.
A cognitive neuropsychology perspective
Cognitive neuropsychologists work to understand specific language impairments, such as aphasia, meaning a deficit in the production or comprehension of language (see Studying Aphasia – The inspiration for the cognitive neuropsychology field). Stroke patients often exhibit different forms of aphasia, especially those with damage to the brain’s left hemisphere – one of the brain’s main centers for language production.
Within the broad area of aphasia, cognitive neuropsychologists study numerous forms of language impairment, trying always to trace the disorder to specific brain areas or cognitive frameworks that span multiple brain areas.
Returning to the example of identifying a “baby,” as explained above, a patient shown an image of a human baby might be unable to correctly identify it - or any other animate or inanimate object. Even more perplexing, the patient may be able to name animate or living objects, such as babies, but unable to name inanimate objects, such as chairs, cars, fences, etc.
In another form of impairment, a patient cannot name objects, yet retains semantic knowledge of the objects, signifying that comprehension of words is unaffected. So the individual could not identify a baby, but would know that the image represents a newborn and what that signifies. Still other patients retain nonperceptual knowledge of objects, such as the ability to classify a baby as a human, but are unable to name perceptual concepts, such as that the baby has two legs, or often smells bad because of a dirty diaper.
Cognitive neuropsychologists study the abilities of brain-injured patients to name animate and inanimate objects for specific reasons. They can, for example, understand the brain better when they observe patients that have the ability to name objects, but not know what the objects mean. This demonstrates that different forms of language impairment link to different areas and/or neural networks of the brain. Obviously, observing patients in this way proves that only one area or network is not responsible for all language abilities.
Using patient studies, cognitive neuropsychologists contribute to the development of treatments and interventions for brain deficits and impairments.
Technology improves research
Technology has also helped cognitive neuropsychologists advance their research into the brain’s networks and regions that mediate language. Computerized axial tomography (CT or CAT), magnetic resonance imaging (MRI), functional magnetic resonance imaging (fMRI), and positron emission tomography (PET) are used in language-brain laboratories across the globe, and lead to an increasing number of discoveries (see article on Neuroimaging).
Studies employing fMRI have uncovered more right-brain areas involved in language processing in addition to a wider distribution of left-brain regions than previously thought.
And these technologies have also highlighted the complexity of language and brain functioning, and the need for more research and advanced understanding in this area.
Careers in studying the brain and language
Because of the applicability of brain-language research to basically every aspect of human life, from understanding how children learn to talk, read, and comprehend both the written and spoken word, to how brain injuries and deficits affect overall functioning, to how aging and memory affects language skills, the need for brain researchers is growing. Both cognitive neuropsychologists and cognitive neuroscientists work in areas that fill this need.
If you find the mechanics of how the brain mediates language fascinating, consider a career in cognitive neuropsychology or cognitive neuroscience. Usually a Ph.D. is required to work as researcher for a university, public or private laboratory. Explore colleges offering psychology degree programs.
Neuroimaging Demonstrates Brain-Language Regions
Neuroimaging techniques such as CT, MRI, fMRI, and PET have led to many important findings about brain functioning and language. These technologies provide cognitive neuropsychologists and cognitive neuroscientists with real-time, or live images of the human brain (and for some neuroscientists, images of animal brains as well).
A series of pioneering studies beginning in the 1980s and continuing through this decade have significantly altered and refined scientists’ understanding of the brain’s normal functioning of language. For example, research on single-word processing has shown widely distributed control networks located in the brain’s left hemisphere for the following distinct functions: spoken word perception; visual word processing (reading); comprehending word meaning; spoken output; and written output.
A study on reading single words highlighted separately involved regions of the left posterior inferior frontal gyrus (Broca’s area) for reading regular and irregular words. The distinct brain areas are attributed to the fact that irregular words can’t be associated with the visual “sounding out” type of word processing. Take, for example, the irregular word echo. Usually the “ch” makes a “c-h” sound as in chop rather than the “k” sound – as in echo. To recognize the word, an individual has to identify the unusual visual form and assign meaning to it.
Knowing how the brain normally processes words helps cognitive neuropsychologists study patients with aphasia, or language impairments. Conversely, cognitive neuropsychologists who study brain injuries and dysfunction contribute to the body of knowledge on normal language-brain functioning.
For example, neuroimaging studies on normal spoken word perception refined previous studies of classical aphasia-based models. These studies showed that the left posterior superior temporal gyrus (Wernicke’s area) has two regions: one serves as a temporary storage area for speech sounds; the second area controls the movements needed to make speech sounds. The second area serves as a mediator or interface between speech sounds, and activating the motor skills needed to make the sounds.