Early Childhood: physical and cognitive development
9-24-10
Physical Development
Body growth slows in early childhood--children gradually become thinner
Posture and balance improve, supporting gains in motor coordination
Individual differences in body size become more pronounced than in infancy and toddlerhood, these reflect both genetic and environmental influences
Skeletal growth:
between age 2 and 6 approximately 45 new epiphyes--growth centers in which cartilage harden into bone--emerge in different areas of the skeleton
by the end of the preschool years, children start to lose their primary teeth
Brain development:
between age 2 and 6 the brain moves from about 70% of it adult weight to about 90%
through formations of synapses, cell death, myelination, and synaptic pruning preschoolers improve in many cognitive and motor skills: physical coordination, perception, attention, memory, language, logical thinking, and imagination
EEG and fMRI measures of neural activity in various cortical regions show rapid growth from early to middle childhood in frontal lobe areas developed to inhibiting impulses and to planning and organizing behavior
the two cerebral hemispheres of the cortex develop at different rates
for most children, the left hemisphere, usually very active during language use, is especially active from 3 to 6 years and then levels off
for most children, the right hemisphere, usually more active during spatial and musical use, increases steadily throughout early childhood
Handedness reflects the greater capacity of one cortical hemisphere, the dominant hemisphere, to carry out skilled motor actions
development of hand preferences
by 2-3 months a rattle is held longer in one hand than another (Fitzgerald et al., 1991)
by 4 months most infants show a clear-cut hand preference in exploring objects (Streri, 2002)
clear grasping preference increases between 7 and 11 months (Hinojosa et al., 2003)
handedness become strongly established by early childhood (McManus et al., 1988)
the proportions of right-handed and left-handed individuals appear to have been approximately the same in ancient (and illiterate) populations as among modern humans: about 83% right-handed, 14% left-handed, 3% ambidextrous (Steele & Mayes, 1995)
there appears a clear genetic component to handedness (Geschwind, 2000; McManus, 2003); a perported dominant gene for right-handedness has been identified and is very common in the human population, most of us have received a copy from each parent (Talan, 1998)
if both your parents are right handed, the odds of your being right-handed is about 92 in 100 (92%); if both your parents are left-handed, your chance of being left-handed is about 50% (Annett, 1999; Clode, 2006)
For the great major of right-handed individuals, language is strongly lateralized in the left hemisphere
For the majority of left-handed individuals, language is also lateralized in the left hemisphere; some, however, show right hemisphere lateralization of language functions or bilateral representation
Left handed individuals are often less strongly lateralized for language functions, which may being both advantage and disadvantages relative to strongly lateralized language functions
other neurological developments:
fibers from the cerebellum, a brain structure that assists in balance and control of body movements, to the cerebral control grow from birth through the preschool years--resulting in gains in both motor development and thinking
the hippocampus, important in verbal memory and spatial understanding, undergoes rapid synapse formation and myelination during the second half of the first year of life
synapse production and myelination in the corpus callosum, a large bundle of fibers connecting the two cortical hemispheres, peak between 3 and 6 years of age
Influences on physical growth and development
Heredity and hormones
Nutrition
Infectious diseases
Childhood injury
Motor development
Gross-motor development
as children's bodies become more streamlined and
Fine-motor development
Individual differences in motor skills
Piaget's theory: the preoperational stage
Piaget's second stage, covering roughly the years 2 to 7, is marked by great increases in representational (symbolic) activity
Language provides our most flexible means of mental representation
Piaget believed that sensorimotor activity lead to internal images of experience, which children learned to label with words
Piaget believed that play, especially make-believe or "pretend" play, gave children the opportunity to practice and strengthen these newly acquired representational schemes
the development of play behavior shows it becoming:
more detached from the real-life circumstances associated with it
less self-centered
more complex, with different combination of schemes
sociodramatic play--pretend play with others, showing up around 2 years of age--shows awareness that make-believe is a representational activity
symbol -- real
until about age 3, children have difficulty with dual representation--viewing a symbolic object as both an object in its own right and a symbol
exposure and experience with diverse symbols (photos, picture books, make-believe, maps) help preschools appreciate dual representation
Researches continue to vary on how real Piaget's preoperational state is
Vygotsky sociocultural theory
Vygotsky believed that children begin to communicate with themselves in much the same way as they converse with others
he believed that language was the foundation for all higher cognitive processes, and that children learn to speak to themselves for self-guidance
strong experimental support for Vygotsky's position has emerged over the past four decades
children's self-directed speech is referred to as private speech
Vygotsky described children's learning as occurring within the zone of proximal development--a range of tasks not yet within the child's ability but possible with assistance
teaching is most effective if it makes use of scaffolding, adjusting the feedback and support to the child's current level of performance
children incorporate their dialogues with adults and make it part of their private speech, which is then used to organize their independent efforts
make believe play served as an ideal social context for fostering cognitive development
information processing theories
focuses on mental strategies that children use to operate on and transform stimuli that flow through their mental systems
Attention
sustained attention increases with advancing age over the first two decades of life
attention, impulse inhibition, focusing, and working memory contribute to increased capacity for goal directed behavior
Memory
preschoolers show quite good recognition memory but their recall memory is much poorer
memory strategies and growing language ability with facilitation memory and recall
Theory of Mind
metacognition -- "thinking about thinking"
by the end of their first year of life, infants view people as intentional being
by age 3--children realize that thinking takes place inside their head
by age four--children realize that both beliefs and desires determine behavior
Individual differences in mental development
Language development