Literacy in the Brain

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Literacy in the Brain

In contrast to language, there are no brain structures designed by evolution to acquire literacy. Experience does not trigger a set of biologically-inclined processes leading to literacy, as in the case of language.

Instead, experience progressively creates the capacity for literacy in the brain through cumulative neural modifications, expressed by Pinker (1995) as “Children are wired for sound, but print is an optional accessory that must be painstakingly bolted on”.

The crucial role of experience in building neural circuitry capable of supporting literacy suggests that attention needs to be given to differences in the degree to which early home environments provide a foundation of pre-literacy skills.

For example, Hart and Risley (2003) report that the sheer number of words that American children from disadvantaged socioeconomic backgrounds were exposed to by the age of 3 lagged behind that of non-disadvantaged children by 30 million word occurrences.

Such limited exposure could be insufficient to support the development of pre-literacy skills in the brain, thereby chronically impeding later reading skills. These children may well be capable of catching up through later experience, but the reality is that they very often do not (Wolf, 2007).

Therefore, of policy relevance from this work: Initiatives aimed at ensuring that all children have sufficient opportunities to develop pre-literacy skills in early childhood are essential.

"Understanding the Brain", The Birth of a Learning Science, 2007, page 86

Language and Developmental Sensitivities: Begin Early (4)

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Language and Developmental Sensitivities (4)
Begin Early

The earlier foreign language instruction begins, the more efficient and effective it is likely to be.

In addition, there is a sensitive period for acquiring the accent of a language (Neville and Bruer, 2001). This aspect of phonological processing is most effectively learned before 12 years of age.

Developmental sensitivities are for very specific linguistic functions, however, and there are other aspects of phonology which do not seem even to have a sensitive period.

In sum, there is an inverse relationship between age and the effectiveness of learning many aspects of language – in general, the younger the age of exposure, the more successful the language learning.

However, for early instruction to be effective, it must be age-appropriate. It would not be useful to take rule-based methods designed for older students and insert them into early childhood classrooms.

It is necessary, in other words, that early foreign language instruction is appropriately designed for young children.

Although the early learning of language is most efficient and effective, it is important to note that it is possible to learn language throughout the lifespan: adolescents and adults can also learn a foreign language, albeit with greater difficulty.

Indeed, if they are immersed in a new language environment, they can learn the language “very well”, though particular aspects, such as accent, may never develop as completely as they would have done if the language had been learned earlier.

There are also individual differences such that the degree and duration of developmental sensitivities vary from one individual to the next. Some individuals are able to master almost all aspects of a foreign language into adulthood.

"Understanding the Brain", The Birth of a Learning Science, 2007, page 86

Grammar and Its Developmental Sensitivities (3)

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Language and Developmental Sensitivities (3)
Grammar

There is also a developmental sensitivity for learning the grammar of a language: the earlier a language is learned, the more efficiently the brain can master its grammar (Neville and Bruer, 2001).

If the brain is exposed to a foreign language between 1 and 3 years of age, grammar is processed by the left hemisphere as in a native speaker but even delaying learning until between 4 and 6 years of age means that the brain processes grammatical information with both hemispheres.

When the initial exposure occurs at the ages of 11, 12 or 13 years, corresponding to the early stage of secondary schooling, brain imaging studies reveal an aberrant activation pattern.

Delaying exposure to language therefore leads the brain to use a different strategy for processing grammar.

This is consistent with behavioural findings that later exposure to a second language results in significant deficits in grammatical processing (Fledge and Fletcher, 1992)

The pattern seems thus to be that early exposure to grammar leads to a highly effective processing strategy, in contrast with alternative, and less efficient, processing strategies associated with later exposure.

"Understanding the Brain", The Birth of a Learning Science, 2007, pages 85 - 86

Phonetic and Its Developmental Sensitivities (2)

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Language and Developmental Sensitivities (2)
Phonetic

There are developmental sensitivities (the windows of learning opportunity) as language circuits are most receptive to particular experience-dependent modifications at certain stages of the individual’s development.

Newborns are born with an ability to discern subtle phonetic changes along a continuous range, but experience with a particular language in the first ten months renders the brain sensitive to sounds relevant to that language (Gopnik, Meltzoff and Kuhl, 1999). For example, the consonant sounds r and l occur along a continuous spectrum, and all newborns hear the sounds this way.

The brains of babies immersed in an English-speaking environment, however, are gradually modified to perceive this continuous spectrogram as two distinct categories, r and l. A prototypical representation of each phoneme is developed, and incoming sounds are matched to these representations and sorted as either r or l.

Babies immersed in a Japanese-speaking environment, by contrast, do not form these prototypes as this distinction is not relevant to Japanese. Instead, they form prototypes of sounds relevant to Japanese, and actually lose the ability to discriminate between r and l by ten months of age. This phenomenon occurs for varied sound distinctions across many languages (Gopnik, Meltzoff and Kuhl, 1999).

Therefore, the brain is optimally suited to acquire the sound prototypes of languages to which it is exposed in the first ten months from birth.

"Understanding the Brain", The Birth of a Learning Science, 2007, page 85