Title: Reading in the Brain: The New Science of How We Read
Author: Stanilaus Dehaene
Scope: 3 stars
Readability: 4 stars
My personal rating: 5 stars
See more on my book rating system.

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Topic of Book

Dehaene overviews the science of how the human brain processes the written word.

Key Take-aways

• Our writing systems evolved by repurposing the neural networks of the brain that evolved among primates.
• The human brain minimizes the “file size” of visual memories by remembering shapes, not pixels.
• Those shapes roughly correspond to the shape of letters in the alphabet.
• This makes it possible for human beings to quickly process the meaning of letters and transform them into ideas.
• If our brain had been different, we would either not be able to read or our writing systems would be very different.

Important Quotes from Book

“a theory of reading is materializing. It postulates that the brain circuitry inherited from our primate evolution can be co-opted to the task of recognizing printed words. According to this approach, our neuronal networks are literally “recycled” for reading.” (p 2)

“writing was born only fifty-four hundred years ago in the Fertile Crescent, and the alphabet itself is only thirty-eight hundred years old. These time spans are a mere trifle in evolutionary terms. Evolution thus did not have the time to develop specialized reading circuits in Homo Sapiens.” (p 4)

“human brain architecture obeys strong genetic constraints, but some circuits have evolved to tolerate a fringe of variability… a range of brain circuits, defined by our genes, provides “pre-representations” or hypotheses that our brain can entertain about future developments in its environment. During brain development, learning mechanism select which pre-representation are best adapted to a given situation. Cultural acquisition rides on this fringe of brain plasticity. Far from being blank slate that absorbs everything in its surroundings, our brain adapts to a given culture by minimally turning its predispositions to a different use…. When we learn a new skill, we recycle some of our old primate brain circuits – insofar, of course, as those circuits can tolerate the change.” (p 7)

“Shapes that resemble Western letters, such as T, F, Y or O, were adopted by inferior temporal neurons because they collectively formed an optimal code, invariant to image transformations, and whose combination could represent an infinity of objects. It is probably that other shapes were added to this alphabet because of their biological relevance.” (p 139)

“By neuronal recycling, I mean the partial or total invasion of a cortical territory initially devoted to a different function, by a cultural invention.” (p 147)

“The ability of this cortical region to recognize words and transmit their identity to other areas results from a two-step evolutionary process:

1. The slow emergence of efficient mechanisms of invariant object recognition that have appeared in the course of mammalian evolution.
2. The rapid cultural adaptation of writing system to fit this cortical niche, in the course of cultural evolution over the past five thousand years…

Our cortex did not specifically evolve for writing… writing evolved to fit the cortex. Our writing systems changed under the constraint that even a primate brain had to find them easy to acquire.