What did you get for Christmas, maybe you got a book? As books are one of the most popular Christmas gifts we ask in today's article "Can Reading Harness Brain Plasticity?"
“Once upon a time in Uzbekistan” is not a way that many neuroscience stories begin. But for this issue on nature and nurture, a key narrative began there that would come to influence debates up to the present day.
Alexander Luria, a Soviet neuropsychologist keenly interested in the relationship between culture and the mind, studied the influence of literacy on styles of argumentation. He wanted to test whether cultural experiences could affect thought patterns. By working with illiterate peasants, he uncovered fascinating examples of how written language seemed to be necessary for abstract thought patterns. His most famous example went something like this:
Putting Text in Context
Although literacy has developed too recently to alter the human genome, it is an integral part of most human societies. For example, if you are on your computer today, you will probably scan more than 500,000 words (not to mention what you see in your time offline) [2]! Furthermore, the practice of reading makes a fascinating case study for the effect of a very special type of nurture on the brain.
Reading text is a multimodal exercise, incorporating visual, auditory, and cognitive/predictive elements of language comprehension. Luria argued (and many today agree) that reading was necessary to provide a scaffold for certain types of abstract thought [1,3]. While fascinating on a purely ethnographic basis, studies such as these still leave many questions to ponder. Though literacy underlies many human interactions, it has only developed on a widespread basis in the last few hundred years. Could this relatively new type of cognitive processing be sufficient to make changes in our brain?
Reading the Signals from Neuroimaging
The hills of Uzbekistan are distant from the labs of today, and indeed, so are the approaches that are used. Although many groups worldwide still do not use written language, they generally aren’t accessible with an MRI scanner in tow. So what do we do now?
Today, our primary knowledge about the effects of reading on the brain comes from longitudinal studies in school-age children. These studies [cf 4,5] demonstrate that literacy appears to co-opt pre-existing language networks in the brain. Notably, the left superior temporal sulcus and inferior frontal areas show robust activation, correlating well with development of reading abilities. These findings are intriguing, but not entirely conclusive. In the countries where these studies were performed, children are legally obligated to go to school and receive formalized instruction. Therefore, a non-literate control group cannot be used to provide more definitive answers about the effects of literacy on the brain.
Recently, researchers have found a way around these challenges, to examine the development of reading skills in a more controlled setting. For example, a group in France has published a set of studies examining the neural correlates of the development of literacy in adults. Essentially, the scientists scanned the brains of adults who had learned to read in childhood using diffusion tensor imaging. They compared them with the brains of adults who had only recently acquired literacy skills. Vast tissue tracts were affected, with literacy acquisition leading to elaboration of tempero-parietal connectivity [6].
A separate study which compared two groups of illiterate adults, one of which received a reading intervention program, found evidence of reading-mediated changes in early visual processing [7]. Other evidence of literacy’s effects on the brain come from people who have reading disorders such as dyslexia. These individuals, contrary to their normally-reading peers, have been shown to demonstrate hypoactivation of several superior temporal areas typically associated with word processing and semantic retrieval [8,9]. Taken together, this work suggests a tightly interlinked series of regions in the brain that are altered through learning to read and whose malfunction may underlie a failure to do so.
Literacy: A Thoroughly Complicated Business
So can we still stand by Luria 80 years later? Yes and no. Although it appears that literacy skills do foster changes in activation and connectivity, we are still a long way from understanding how these changes might underlie certain types of abstract thought (and beliefs about polar bears). Moreover, there are several obstacles to getting the full picture about reading and the brain. At the end of the day, reading is a fundamentally culture-bound phenomenon. It is deeply influenced by the values and educational emphases of the society in which it develops.
As neuroimaging studies progress, we should not forget where all these questions started. Though a trip through the wilderness is certainly not for the faint of heart, it may still be the best way to integrate neuroscientific, ethnographic, and linguistic inquiry. And with a business as complicated as understanding literacy, it may be where we need to return.
[1] Luria, Cognitive Development: Its Cultural and Social Foundations, 1976
[2] Bunz, “Is the link economy of UK news sites managing or making abundance?” in PDA: The digital content blog, Nov 2, 2009
[3] Nell, Neuropsych Rev, 1999
[4] Berl et al, Brain Lang, 2010
[5] Horowitz-Kraus et al, Front Hum Neurosci, 2014
[6] de Schotten et al, Cereb Cort, 2014
[7] Boltzmann and Rüsseler, BMC Neuroscience, 2014
[8] Christodoulou et al, PloS One, 2014
[9] Eicher and Gruen, Mol Genet Metab, 2013
by Constance Holman, PhD Student AG Schmitz
This article originally appeared 2014 in CNS Volume 7, Issue 3, Nature vs Nurture
“Once upon a time in Uzbekistan” is not a way that many neuroscience stories begin. But for this issue on nature and nurture, a key narrative began there that would come to influence debates up to the present day.
Alexander Luria, a Soviet neuropsychologist keenly interested in the relationship between culture and the mind, studied the influence of literacy on styles of argumentation. He wanted to test whether cultural experiences could affect thought patterns. By working with illiterate peasants, he uncovered fascinating examples of how written language seemed to be necessary for abstract thought patterns. His most famous example went something like this:
Many more such examples (dealing with everything from describing shapes to objects to self-reference) were collected in Luria’s bestseller, Cognitive Development: its Social and Cultural Foundations [1]. It went on to be a fundamental text in both neuroscience and anthropology.Luria: “In the North, there is snow, and all bears are white. Novaya Zemlya is in the far North. What color are the bears there?”Peasant: “I don’t know. I’ve never been to the far North. I saw a black bear here once.”
 |
| via Wikimedia Commons |
Putting Text in Context
Although literacy has developed too recently to alter the human genome, it is an integral part of most human societies. For example, if you are on your computer today, you will probably scan more than 500,000 words (not to mention what you see in your time offline) [2]! Furthermore, the practice of reading makes a fascinating case study for the effect of a very special type of nurture on the brain.
Reading text is a multimodal exercise, incorporating visual, auditory, and cognitive/predictive elements of language comprehension. Luria argued (and many today agree) that reading was necessary to provide a scaffold for certain types of abstract thought [1,3]. While fascinating on a purely ethnographic basis, studies such as these still leave many questions to ponder. Though literacy underlies many human interactions, it has only developed on a widespread basis in the last few hundred years. Could this relatively new type of cognitive processing be sufficient to make changes in our brain?
Reading the Signals from Neuroimaging
The hills of Uzbekistan are distant from the labs of today, and indeed, so are the approaches that are used. Although many groups worldwide still do not use written language, they generally aren’t accessible with an MRI scanner in tow. So what do we do now?
Today, our primary knowledge about the effects of reading on the brain comes from longitudinal studies in school-age children. These studies [cf 4,5] demonstrate that literacy appears to co-opt pre-existing language networks in the brain. Notably, the left superior temporal sulcus and inferior frontal areas show robust activation, correlating well with development of reading abilities. These findings are intriguing, but not entirely conclusive. In the countries where these studies were performed, children are legally obligated to go to school and receive formalized instruction. Therefore, a non-literate control group cannot be used to provide more definitive answers about the effects of literacy on the brain.
 |
| by Mark Larson via Flickr, "Use your library often!" |
Recently, researchers have found a way around these challenges, to examine the development of reading skills in a more controlled setting. For example, a group in France has published a set of studies examining the neural correlates of the development of literacy in adults. Essentially, the scientists scanned the brains of adults who had learned to read in childhood using diffusion tensor imaging. They compared them with the brains of adults who had only recently acquired literacy skills. Vast tissue tracts were affected, with literacy acquisition leading to elaboration of tempero-parietal connectivity [6].
A separate study which compared two groups of illiterate adults, one of which received a reading intervention program, found evidence of reading-mediated changes in early visual processing [7]. Other evidence of literacy’s effects on the brain come from people who have reading disorders such as dyslexia. These individuals, contrary to their normally-reading peers, have been shown to demonstrate hypoactivation of several superior temporal areas typically associated with word processing and semantic retrieval [8,9]. Taken together, this work suggests a tightly interlinked series of regions in the brain that are altered through learning to read and whose malfunction may underlie a failure to do so.
Literacy: A Thoroughly Complicated Business
So can we still stand by Luria 80 years later? Yes and no. Although it appears that literacy skills do foster changes in activation and connectivity, we are still a long way from understanding how these changes might underlie certain types of abstract thought (and beliefs about polar bears). Moreover, there are several obstacles to getting the full picture about reading and the brain. At the end of the day, reading is a fundamentally culture-bound phenomenon. It is deeply influenced by the values and educational emphases of the society in which it develops.
As neuroimaging studies progress, we should not forget where all these questions started. Though a trip through the wilderness is certainly not for the faint of heart, it may still be the best way to integrate neuroscientific, ethnographic, and linguistic inquiry. And with a business as complicated as understanding literacy, it may be where we need to return.
[1] Luria, Cognitive Development: Its Cultural and Social Foundations, 1976
[2] Bunz, “Is the link economy of UK news sites managing or making abundance?” in PDA: The digital content blog, Nov 2, 2009
[3] Nell, Neuropsych Rev, 1999
[4] Berl et al, Brain Lang, 2010
[5] Horowitz-Kraus et al, Front Hum Neurosci, 2014
[6] de Schotten et al, Cereb Cort, 2014
[7] Boltzmann and Rüsseler, BMC Neuroscience, 2014
[8] Christodoulou et al, PloS One, 2014
[9] Eicher and Gruen, Mol Genet Metab, 2013
by Constance Holman, PhD Student AG Schmitz
This article originally appeared 2014 in CNS Volume 7, Issue 3, Nature vs Nurture
