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Brain Development
Sensitive Periods in Brain Development – Implications for Education Policy
Michael SC Thomas and Victoria CP Knowland
Developmental Neurocognition Laboratory, School of Psychology, Birkbeck College, University of London
Abstract
Functional plasticity is the ability to change behaviour based on experience. Structural changes in the brain occurring with increasing age
are sometimes associated with a reduction in functional plasticity, leading to the idea of sensitive periods in development. In this article
we assess the implications of recent findings on sensitive periods in brain development for educational policy. We address three points.
Can the educational curriculum be optimised by teaching particular subjects at a point of maximum plasticity for the brain systems
involved? Do some skills need to be acquired later so that acquisition is optimised only after children reach a certain age? How should
educational practice be adjusted to optimise learning for individuals who have passed the age of maximum plasticity?
Keywords
Brain plasticity, cognitive development, education, sensitive periods
Disclosure: This work was supported by UK Medical Research Council Grant G0300188 and EC grant 0209088 (NEST).
Received: 6 March 2009 Accepted: 8 June 2009
Correspondence: Michael Thomas, Developmental Neurocognition Laboratory, School of Psychology, Birkbeck College, University of London, Malet Street, Bloomsbury,
London, WC1E 7HX, UK. E: m.thomas@bbk.ac.uk
One of the main characteristics of the human brain is its plasticity. nevertheless retained; windows of plasticity do not shut suddenly
Functional plasticity is the ability to change behaviour based on or firmly. Research has indicated that sensitive periods are present
experience. When children are exposed to specially structured in many domains of human cognition, particularly in perceptual
environments such as the instruction they experience in schools, systems.
1,2
However, there appear to be multiple sensitive periods
they can learn high-level cognitive skills that are specific to their with different time courses, both across perceptual domains and
culture. Acquisition of these skills can take weeks, months or years. within a given domain. For example, within the auditory domain
The result can be a literate child, a numerate child, a multilingual there are different sensitive periods for different facets of speech
child, an artistic child or a child who can reason logically or play processing and other periods with different timing related to basic
sports and musical instruments. One characteristic that the human aspects of music perception in humans; in the primate visual
brain shares with other species is that it exhibits marked changes system there are different sensitive periods related to amblyopia,
with age. These include the loss of neurons and the pruning of visual acuity, motion perception and face processing.
3
connections. In humans, up to half of all synapses (the structures
through which neurons communicate) are lost from the neocortex The relationship between these sensitive periods and particular
during late childhood and adolescence. Such structural changes are properties of underlying brain mechanisms is still an active area of
sometimes associated with a loss of functional plasticity, leading to research, particularly when investigating those properties that
the idea of sensitive periods in development. In this article we differentiate the sensitive periods of the various neural subsystems.
assess the implications for educational policy of recent findings on Diverse neurocomputational mechanisms may be responsible for
sensitive periods in brain development. reductions in plasticity, including loss of resources, competition
effects and entrenchment.
4
However, differences in sensitive
Current Knowledge About Sensitive Periods periods are likely to be related to the anatomical development of
A sensitive period represents a window within which the effects of specific cortical regions, and may coincide with the plateau of high
environmental stimulation on brain structure and function are synaptic density present from late infancy to late childhood in most
maximised. The main source of empirical evidence that informs our cortical areas except for primary sensory areas, which show earlier
understanding of sensitive periods is the rate and upper limit of reductions.
5
Synapses are generated spontaneously when axons
behavioural change that individuals can achieve at different ages. and dendrites meet, and only those that contribute to function are
Two other sources provide converging evidence: the effects of early stabilised and retained. Early overproduction of synapses may
deprivation on subsequent development, such as transient therefore be viewed as a resource to change function. One
impairments in vision or hearing, and the ability of individuals to influential view is that sensitive periods in human cognitive
recover from brain damage experienced at different ages. After the development are intrinsic to the process that produces the
closing of the sensitive period, some level of plasticity is functional structure of the adult brain. The adult brain is a complex
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