Sensitive Periods in the Language

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Sensitive Periods in the Language

Neville (OECD, 2000) has noted that second language learning involves both comprehension and production calling for the mastery of different processes.

Two of these aspect(About comprehension) – grammar and Semantic processing – rely on different neural systems within the brain. Grammar processing relies more on frontal regions of the left hemisphere, whereas semantic processing (e.g., vocabulary learning) activates the posterior lateral regions of both the left and right hemispheres. The later that grammar is learned, the more active is the brain in the learning process.

Instead of processing grammatical information only with the left hemisphere, late learners process the same information with both hemispheres. This indicates that delaying exposure to language leads the brain to use a different strategy when processing grammar. Confirmatory studies have additionally shown that the subjects with this bilateral activation in the brain had significantly more difficulty in using grammar correctly – the bilateral activation indicates greater difficulty in learning. Thus, the earlier the child is exposed to the grammar of a foreign language, the easier and faster it is mastered.

Semantic learning, however, continues throughout life and is not constrained in time.

Another example of sensitive periods is during the acquisition of speech sounds (phonemes). Studies show that young infants in the first few months of their lives are capable of discriminating the subtle but relevant differences between similar-sounding consonants and between similar sounding vowels, for both native and foreign languages. Newborn babies can learn to discriminate difficult speech-sounds contrasts in a couple of hours even while they are sleeping, contrary to the view that sleep is a sedentary state when such capacities as attention and learning are reduced or absent (Cheour et al., 2002a).

During the first year of life, however, this capacity in relation to non-native language is narrowed down as sensitivity to the sounds of their native language grows. This decline in non-native perception occurs during the first year of life, with the sharpest decline between eight and ten months (Werker, 2002; Kuhl, 1979). This change enhances the efficiency of the brain function by adapting to the natural environment.

It should be noted that it is not sufficient to just make young infants listen to foreign languages through CDs in order to maintain the sensitivity towards foreign speech sounds.

The acquisition of non-native speech sounds is nevertheless possible outside the sensitive period. Cheour et al. (2002b) have shown that 3- to 6-year-old children can also learn to distinguish non-native speech sounds in natural language environment within two months without any special training. McCandliss (2000) suggests that, with short-term training, Japanese native adults can learn to distinguish the speech sounds r and l.

However, as the most important aspect of language learning is to be able to communicate which does not necessarily require an accurate distinction of speech sounds, it is an open question whether it is necessary to invest time in training to distinguish foreign speech sounds, bearing in mind the level of accuracy required in different situations.

"Understanding the Brain: The Birth of a Learning Science", 2007, pages 44-45

Childhood Plasticity (2) (Only Til 3 Years?)

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Childhood Plasticity (2)
Only Until 3 Years Old?

The educational question is then how best to build upon the already-existing competence of children. Is there an optimal timing and are there any preferred modes of learning?

There has long been a general belief among the non-specialists that from birth to 3 years of age, children are the most receptive to learning (Bruer, 1999). On this view, if children have not been exposed fully and completely to various stimuli, they will not be able to recuperate the benefits of early stimulus later on in life.

However, even for the skills for which sensitive periods exist, the capacity to learn will not be lost even after the sensitive period. While there is no scientific evidence that over-stimulating a normal, healthy infant has any beneficial effect, there is evidence that it may be a waste of time (Sebastian, 2004).

The findings on which these arguments are based relate to very basic functioning such as vision; it would not be appropriate to apply this directly to the learning of cognitive skills. For more comprehensive understanding of how the experience during early childhood affects later development, a large cohort study would be required.

Sensitive periods do nevertheless exist in certain areas of learning such as language acquisition.

"Understanding the Brain: The Birth of a Learning Science", 2007, page 44

Plasticity and Sensitive Periods

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Plasticity and Sensitive Periods

Neuroscientists have known for some time that the brain changes significantly over the lifespan as a response to learning experiences. This flexibility of the brain to respond to environmental demands is called plasticity.

The brain is physically modified through strengthening, weakening, and elimination of existing connections, and the growth of new ones. The degree of modification depends on the type of learning that takes place, with long-term learning leading to more profound modification.

The brain’s ability to remain flexible, alert, responsive and solution-oriented is due to its lifelong capacity for plasticity. Before, it was thought that only infant brains were plastic. This was due to the extraordinary growth of new synapses paralleled with new skill acquisition.

However, data uncovered over the last two decades have confirmed that the brain retains its plasticity over the lifespan. And because plasticity underlies learning, we can learn at any stage of life albeit in somewhat different ways in the different stages (Koizumi, 2003; OECD, 2002).

Plasticity can be classified into two types: experience-expectant and experience-dependent.

The plasticity experience-expectant describes the genetically-inclined structural modification of the brain in early life.

The plasticity experience-dependent the structural modification of the brain as a result of exposure to complex environments over the lifespan.

Many researchers believe that experience-expectant plasticity characterises species-wide development: it is the natural condition of a healthy brain, a feature which allows us to learn continuously until old age.

In parallel to plasticity, learning can also be described as experience-expectant or experience-dependent.

Experience-expectant learning takes place when the brain encounters the relevant experience, ideally at an optimal stage termed a “sensitive period”. Sensitive periods are the times in which a particular biological event is likely to occur best.

Scientists have documented sensitive periods for certain types of sensory stimuli such as vision and speech sounds, and for certain emotional and cognitive experiences, such as language exposure.

However, there are many mental skills, such as vocabulary acquisition and the ability to see colour, which do not appear to pass through tight sensitive periods. These can be considered as experience-dependent learning that takes place over the lifespan.

The different types of plasticity play a different role in different stages of life. The following section takes the three different stages of life, namely early childhood, adolescence, and adulthood (including ageing adults), and describes the distinctive characteristics of the learning process in each stage.

"Understanding the Brain: The Birth of a Learning Science", 2007, page 42

The Brain Plasticity

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The Brain Plasticity

The brain is capable of learning because of its flexibility. It changes in response to stimulation from the environment. This flexibility resides in one of the intrinsic properties of the brain – its plasticity.

The mechanism operates in various ways at the level of the synaptic connections. Some synapses may be generated (synaptogenesis), others eliminated (pruning), and their effectiveness may be moulded, on the basis of the information processed and integrated by the brain.

The “traces” left by learning and memorisation are the fruit of these modifications.

Plasticity is consequently a necessary condition for learning and an inherent property of the brain; it is present throughout a whole lifetime.

The concept of plasticity and its implications are vital features of the brain. Educators, policy makers and all learners will all gain from understanding why it is possible to learn over a whole lifetime and indeed brain plasticity provides a strong neuroscientific argument for “lifelong learning”.

Would not primary school be a good place to start teaching learners how and why they are capable of learning?

"Understanding the Brain: The Birth of a Learning Science", 2007, page 30

The Memory

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The Memory

During the learning process, traces are left by the processing and integration of perceived information.

This is how memory is activated. Memory is a cognitive process enabling past experiences to be remembered, both in terms of acquiring new information (development phase of the trace) and remembering information (reactivation phase of this trace).

The more a trace is reactivated, the more “marked” memory will be. In other words, it will be less vulnerable and less likely to be forgotten.

Memory is built on learning, and the benefits of learning persist thanks to it.These two processes have such a profound relationship that memory is subject to the same factors influencing learning.

This is why memorisation of an event or of information can be improved by a strong emotional state, a special context, heightened motivation or increased attention.

Learning a lesson too often means being able to recite it. Training and testing are usually based on retrieving and therefore on memorising information often to the detriment of mastering skills and even of understanding content.

Is this role given to memory skills in learning justified? This is a pivotal question in the field of education, and is beginning to attract the attention of neuroscientists.

"Understanding the Brain: The Birth of a Learning Science", 2007, page 29

The Intelligence

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The Intelligence

The concept of intelligence has always been a subject of controversy. Can a single concept account for all of the intellectual faculties of an individual? Can these faculties be separated and measured? And in particular, what do they show and predict about the cerebral functioning of an individual and about social behaviour?

The notion of intelligence evokes “skills”, whether they are verbal skills, spatial skills, problem-solving skills or the very elaborate skill of dealing with complexity.

However, all of these aspects neglect the concept of “potential”. Yet, neurobiological research on learning and cognitive functions clearly shows that these processes undergo constant evolution and are dependent on a number of factors, particularly environmental and emotional ones.

This means that a stimulating environment should offer each individual the possibility to cultivate and develop his/her skills.

From this point of view, the many attempts to quantify intelligence using tests (such as IQ measurements or others) are too static and refer to standardised and culturally (sometimes even ideologically) biased faculties.

Based on a priori assumptions, intelligent tests are restrictive and therefore problematic. Based on this “intelligence calculation” or the debatable assignation of individuals to different levels of intelligence, what should be concluded for the practices or even the choices related to career orientation?

"Understanding the Brain: The Birth of a Learning Science", 2007, page 27

The Emotions

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The Emotions

Emotional components have long been neglected in institutional education. Recent contributions of neuroscientists are helping to remedy this deficiency by revealing the emotional dimension of learning.

As opposed to “affect”, which is their conscious interpretation, emotions arise from cerebral processes and are necessary for the adaptation and regulation of human behaviour.

Emotions are complex reactions generally described in terms of three components: a particular mental state, a physiological change and an impulsion to act.

Therefore, faced with a situation perceived as dangerous, the reactions engendered will simultaneously consist of a specific cerebral activation of the circuit devoted to fear, body reactions typical of fear (e.g. accelerated pulse, pallor and perspiring) and the fight-or-flight reaction.

Each emotion corresponds to a distinct functional system and has its own cerebral circuit involving structures in what we call the “limbic system” (also known as the “seat of the emotions”), as well as cortical structures, mainly the prefrontal cortex which plays a prime role in regulating emotions.

Incidentally, the prefrontal cortex matures particularly late in human beings, concluding its development in the third decade of an individual’s development.

This means that cerebral adolescence lasts longer than was, until recently, thought, which helps to explain certain features of behaviour: the full development of the prefrontal cortex, and therefore the regulation of emotions and compensation for potential excesses of the limbic system, occur relatively late in an individual’s development.

Continual exchanges make it impossible to separate the physiological, emotional and cognitive components of a particular behaviour.

The strength of this interconnectivity explains the substantial impact of emotions on learning.

If a positively perceived emotion is associated with learning, it will facilitate success, whereas a negatively perceived emotion will result in failure.

"Understanding the Brain: The Birth of a Learning Science", 2007, page 25

Dispelling “Neuromyths”

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Dispelling “Neuromyths”

Over the past few years, there has been a growing number of misconceptions circulating about the brain – “neuromyths”. They are relevant to education as many have been developed as ideas about, or approaches to, how we learn.

These misconceptions often have their origins in some element of sound science, which makes identifying and refuting them the more difficult. As they are incomplete, extrapolated beyond the evidence, or plain false, they need to be dispelled in order to prevent education running into a series of dead-ends.

Each “myth” or set of myths is discussed in terms of how they have emerged into popular discourse, and of why they are not sustained by neuroscientific evidence.

They are grouped as follows:

• “There is no time to lose as everything important about the brain is decided by the age of three.”
  
• “There are critical periods when certain matters must be taught and learnt.”
  
• “But I read somewhere that we only use 10% of our brain anyway.”
  
• “I’m a ‘left-brain’, she’s a ‘right-brain’ person.”
  
• “Let’s face it – men and boys just have different brains from women and girls.”
  
• “A young child’s brain can only manage to learn one language at a time.”
  
• "Improve your memory!"
  
• "Learn while you sleep!"

"Understanding the Brain: The Birth of a Learning Science", 2007, page 16

Numeracy and the Brain

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Numeracy and the Brain

Numeracy, like literacy, is created in the brain through the synergy of biology and experience.

Just as certain brain structures are designed through evolution for language, there are analogous structures for the quantitative sense.

And, also as with language, genetically-defined brain structures alone cannot support mathematics as they need to be co-ordinated with those supplementary neural circuits not specifically destined for this task but shaped by experience to do so.

Hence, the important role of education – whether in schools, at home, or in play; and hence, the valuable role for neuroscience in helping address this educational challenge.

Although the neuroscientific research on numeracy is still in its infancy, the field has already made significant progress in the past decade. It shows that even very simple numerical operations are distributed in different parts of the brain and require the co-ordination of multiple structures.

The mere representation of numbers involves a complex circuit that brings together sense of magnitude, and visual and verbal representations.

Calculation calls on other complex distributed networks, varying according to the operation in question: subtraction is critically dependent on the inferior parietal circuit, while addition and multiplication engage yet others.

Understanding the underlying developmental pathways to mathematics from a brain perspective can help shape the design of teaching strategies.

Different instructional methods lead to the creation of neural pathways that vary in effectiveness: drill learning, for instance, develops neural pathways that are less effective than those developed through strategy learning.

Support is growing from neuroscience for teaching strategies which involve learning in rich detail rather than the identification of correct/incorrect responses.

This is broadly consistent with formative assessment.Though the neural underpinnings of dyscalculia – the numerical equivalent of dyslexia – are still under-researched, the discovery of biological characteristics associated with specific mathematics impairments suggests that mathematics is far from a purely cultural construction: it requires the full functioning and integrity of specific brain structures.

It is likely that the deficient neural circuitry underlying dyscalculia can be addressed through targeted intervention because of the “plasticity” – the flexibility – of the neural circuitries involved in mathematics.

"Understanding the Brain: The Birth of a Learning Science" 2007, page 16

Language, Literacy and the Brain

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Language, Literacy and the Brain

The brain is biologically primed to acquire language right from the very start of life; the process of language acquisition needs the catalyst of experience.

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 learning – and neuroscience has started to identify how the brain processes language differently among young children compared with more mature people.

This understanding is relevant to education policies especially regarding foreign language instruction which often does not begin until adolescence.

Adolescents and adults, of course, can also learn a language anew, but it presents greater difficulties.

"Understanding the Brain: The Birth of a Learning Science", 2007, page 15

The Importance of Environment

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The Importance of Environment

Finding from brain researcher indicate how nurturing is crucial to the learning process and are beginning to provide indication of appropriate learning environments.

Many of environmental factors conducive to improved brain functioning are every matters:

• The quality of social environment and interactions.


• Nutrition.


• Physical exercise.


• Sleep.

Which may seen too obvious and easily overlooked in their impact in the education.

By conditioning our minds and our bodies correctly, it is possible to take advantage of the brain´s potential for plasticity and to facilitate the learning process.

This is calls for holistic approaches which recognise the close interdependence of physical and intellectual well-being and the close interplay of emotional and cognitive.

"Understanding the Brain: The Birth of a Learning Science", 2007, page 14

How the Brain Learns Throughout Life

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How the Brain Learns Throughout Life

Neuroscientists have well established that the brain has a highly robust and well-developed capacity to change in response to environmental demands, a process called plasticity.

This involves creating and strengthening some neuronal connections and weakening or eliminating others.

The degree of modification depends on the type of learning that takes place, with long-term learning leading to more profound modification.

It also depends on the period of learning, with infants experiencing extraordinary growth of new synapses. But a profound message is that plasticity is a core feature of the brain throughout life

"Understanding the Brain: The Birth of a Learning Science", 2007, page 13