Physical Development: Brain & Perception

Principles of Physical Development Children’s bodies are dynamic systems Different parts of the body mature at different rates Functioning becomes increasingly differentiated –Differentiation – an increase from general to more specific functioning over the course of development Functioning becomes more integrated –Integration – an increasing coordination of body parts over the course of development Every child follows a different growth curve Physical development is characterized by both qualitative and quantitative changes Teresa M. McDevitt and Jeanne Ellis Ormrod Child Development and Education, third edition Copyright ©2007 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved.

The Brain and Its Development Teresa M. McDevitt and Jeanne Ellis Ormrod Child Development and Education, third edition Copyright ©2007 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Neurons in the Brain

The Brain and Its Development Teresa M. McDevitt and Jeanne Ellis Ormrod Child Development and Education, third edition Copyright ©2007 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Neuron – cell that transmits information to other cells; also called nerve cell Axon – armlike part of a neuron that sends information to other neurons Dendrite – branchlike part of a neuron that receives information from other neurons Synapse – junction between two neurons Glial cell – brain or nervous system cell that provides structural or functional support for one or more neurons

Structures and Functions Teresa M. McDevitt and Jeanne Ellis Ormrod Child Development and Education, third edition Copyright ©2007 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Structure of the Human Brain

Teresa M. McDevitt and Jeanne Ellis Ormrod Child Development and Education, third edition Copyright ©2007 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Developmental Changes in the Brain Developmental Period Distinctive Neurological Changes Prenatal The primary structures of the brain emerge Neurons are formed Cortex matures Infancy Brain forms connections Dendrites expand their reach and complexity Synapses grown in density Synaptic pruning begins Brain searches for stimuli Brain becomes differentiated Myelinization begins

Teresa M. McDevitt and Jeanne Ellis Ormrod Child Development and Education, third edition Copyright ©2007 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Developmental Changes in the Brain Developmental Period Distinctive Neurological Changes Middle Childhood Synaptic pruning strengthens connections Synaptic pruning in the prefrontal areas improves memory and attention. Myelinization continues to protect neurons & speed transmission of signals New synapses may reflect learning through experience.

Teresa M. McDevitt and Jeanne Ellis Ormrod Child Development and Education, third edition Copyright ©2007 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Developmental Changes in the Brain Developmental Period Distinctive Neurological Changes Adolescence Myelination continues to protect neurons where planning & other complex thinking occurs Brain hemispheres become specialized Synaptic pruning continues to improve memory & attention Cortex matures Fiber pathways that support speech & motor functions continue to mature Fibers connecting language centers slow in growth rate Analysis of emotional expressions matures

Newborn ("neonate") states 1.Sleep 2.Crying 3.Reflexes Reflexes inborn, automatic response to specific stimulation window to neurological intactness most eventually disappear (eye blinking and sucking reflex are permanent)

Perceptual abilities 1. Vision - least mature of all the senses - retina still immature at birth, muscles of the lens weak - by 3 mos. infant can focus as well as an adult - by age 6 months, adult level visual acuity "20/20 vision"

Newborn 4 weeks 8 weeks 3 months 6 months Source: Infant Vision Lab, Indiana Univ. Infant visual development

Perceptual abilities… 2. Hearing prenatal hearing (learning?) "Cat in the Hat study" hearing of newborns is excellent newborns demonstrate preference for Mother's voice and native language as young as 2 months old listen longer to human speech vs. structurally similar nonspeech sounds between 6-8 mos. they filter out sounds that are not important in their own language LSCP Infant Lab, Paris

Perceptual abilities… 3. Intermodal perception infants coordinate sound and sight; upset if not synchronous by 1 month, infant shows anxiety if see mother but her voice comes from another place

Imitative ability even newborns can imitate by 2-3 mos. seems to disappear, but researchers argue the infant is instead more interested in other motor skills & social games--the capacity is still present

Making sense of their world early preference for faces, symmetry, patterns, vertical orientation; by 3 mos. they prefer FACES over similar complex figures

Making sense of their world by 3 mos. can distinguish mother's photograph from other women at 4 mos. a perceptual revolution occurs. Probably due to complex cortical reorganization. Baby can see 3-D, stereoscopic, locate sounds with precision

According to Piaget, infants do not yet have ideas or concepts about things (nor a memory for people or objects if they are absent)...they only interact with objects at a sensorimotor level (until 18 mos. or 2 yrs of age). But recent research suggests otherwise... What methods can we use to understand what infants may know if they can’t tell us?

Environmental/Cultural influences? Most of perceptual ability is considered to be maturationally-determined But deprivation can affect motor development (Example: Iranian orphanage, no toys, left in cribs, at 2 years still not walking; only 15 percent of Iranian orphans walked alone by age 3). Interventions are highly effective (training caregivers to be responsive and provide stimulation--but not overstimulate!);

Individual differences? Observed individual (and cultural) differences in motor development are compatible with a Dynamic Systems Theory explanation Child reorganizes existing motor skills (e.g., kicking, rocking on all 4s, reaching) into new patterns of behavior (crawling) which leads to more effective exploration skills