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Key points
- Most people in the history of our species have not been literate.
- Acquiring a practiced naturalness with reading renders it easy, effortless, unconscious, and automatic.
- Becoming literate involves reallocating left hemisphere resources that are normally used for face processing.
Culture has sculpted your brain in a fashion different from most of the members of our species who have ever lived. A search for evidence for that claim need proceed no further than the fact that you have been able to read these first two sentences. You, in short, are literate, and literacy changes brains.
Most humans, across the entire span of time that our species has existed, have not been literate. This means that most twenty-first-century humans, existing when the literacy rate among adults worldwide is around 85 percent, differ neurologically and psychologically from most of our predecessors—both historic and prehistoric. For example, as recently as 1820, only about 12 percent of adults were literate, and, of course, no one was literate prior to the invention of writing and reading about 5,500 years ago.
Rewiring Brains That Read
In modern societies, large numbers of children spend years learning and practicing reading. With intensive and prolonged practice, literacy shifts from a slow, effortful, conscious, and deliberate process to one that becomes fast, effortless, (mostly) unconscious, and automatic.
Reading and writing acquire what I have called a “practiced naturalness.” Like the processing of speech in our native languages, the processing of text becomes mandatory. Just as people cannot help but hear utterances in their native languages as utterances in their native languages, literate individuals cannot help but read recognizable text. Persons who are literate in English cannot look at this text without instantly reading it. These capacities are not under conscious control.
Critical neural processing underlying the ability to read occurs in the brain’s left ventral occipitotemporal area. The area in question is close to other areas of the temporal lobe concerned with speech and language processing and with object recognition.
This cortical region does not handle all written symbols though. So, for example, damage to this area impairs or eradicates the ability to read but has no impact on the recognition of numerals or the ability to carry out mathematical calculations.
Joseph Henrich points out that culture quite literally rewires human brains when people become literate. Learning how to read is not just a matter of training up neural networks in this brain area. Acquiring literacy commandeers this left ventral occipitotemporal region, which is devoted to face recognition in the non-literate majority of humans who have walked the earth.
The brains of literate people devote fewer neural resources to the task of face recognition than do the brains of nonliterate people. Face recognition in the literate exhibits a decided right hemisphere bias and alters the character of the processing involved.
Implications of Culture Rewiring Brains
This process of the acquisition of literacy rewiring brains has at least two interesting implications.
The first concerns proposals about cultural evolution. The overwhelming emphasis in the literature on cultural evolution has been on gene-culture coevolution, which focuses principally on how changes in the cultural environment can affect genes. Here, though, is a case of cultural arrangements (the invention and acquisition of literacy) having a direct impact on human biology (brain wiring) without changing anything about the foundational genetic arrangements.
The second implication concerns the interpretation of relevant scientific findings. Experimental results concerning face recognition tasks show a clear bias for right hemisphere processing. Cross-cultural experimentation with East Asians yields similar results. But the East Asian participants in such studies are also literate.
As Henrich notes, “It was inferred that this hemispheric bias in facial processing was a basic feature of human neurocognitive functioning—not a cultural by-product of deep literacy.” It seems a safe bet that this is probably not the only instance of such an inference from experimental findings that misses the role that cultural arrangements play in shaping those outcomes.
References
Henrich, Joseph. (2020). The WEIRDest People in the World: How the West Became Psychologically Peculiar and Particularly Prosperous. New York: Farrar, Strauss, and Giroux.
Richerson, P. J., Boyd, R., and Henrich, J. (2010). Gene-culture coevolution in the age of genomics. PNAS 107 (supplement 2), 8985-8992.
Ventura, P., Fenandes, T. Cohen, L., Morais, J., and Kolinsky, R. (2013). Literacy acquisition reduces the influence of automatic holistic processing of faces and houses. Neuroscience Letters 554, 105-109.
McCauley, Robert. N. (2011). Why Religion Is Natural and Science Is Not. New York: Oxford University Press.
