Developmental Psychology Chapter 4 Notes PDF

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Dr. Van Allen...

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Chapter 4: Physical Development in Infancy and Toddlerhood Tuesday, October 4, 2016 7:49 PM

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Body growth o Changes in body size and fat makeup  Height increases 50% by age 1, 75% by age 2  Weight doubles by 5 months, triples by 1 year, quadruples by 2 years  Baby fat increases and peaks about 9 months o Individual and group differences in size and rate of growth  Group differences  Gender  Girls have more fat and are shorter and lighter than boys.  Girls have a higher skeletal age.  Ethnic  African-American children develop faster.  Asian children develop more slowly.  Individual differences  Children grow at different rates.  Skeletal age: a measure of bone development; the best estimate of a child's physical maturity o Changes in body proportions  Cephalocaudal trend  "Head to tail"  Lower part of body grows later than the head  Proximodistal trend  "Near to far"  Extremities grow later than the head, chest, and trunk Brain development o At birth, the brain is nearer to its adult size than any other physical structure. o Development of neurons  Neurons: nerve cells that store and transmit information  Synapses: tiny gaps where fibers from different neurons come close together but do not touch  Neurotransmitters: chemicals released by neurons that cross the synapse to send messages to one another  Programmed cell death: an aspect of brain growth that makes space for connective structures  Synaptic pruning: a process that returns neuros not needed at the moment to an uncommitted state so they can support future development  Glial cells: cells that are responsible for myelination  Myelination: the coating of neural fibers with an insulating fatty sheath that improves the efficiency of message transfer o Neurobiological methods  Electroencephalogram: brain-wave patterns are examined for stability and organization  Event-related potentials: detects the general location of brain-wave activity

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Neuroimaging techniques: yield detailed, three-dimensional computerized pictures of the entire brain and its active areas  Functional magnetic resonance imaging: detects changes in blood flow and oxygen metabolism throughout the brain magnetically  Positron emission tomography: depends on x-ray photography  Near-infrared spectroscopy: thin, flexible optical fibers attached to the scalp using a head cap that examines only the functioning of the cerebral cortex o Development of the cerebral cortex  Cerebral cortex: surrounds the rest of the brain, resembling half of a shelled walnut and accounts for 85% of the brain's weight and contains the greatest number of neurons and synapses  Regions of the cerebral cortex  Prefrontal cortex: responsible for thought - in particular, consciousness, inhibition of impulses, integration of information, and use of memory, reasoning, planning, and problem-solving  Undergoes rapid growth in the preschool and school years and in adolescence  Lateralization of the cerebral cortex  Left hemisphere  Verbal abilities  Positive emotion  Sequential, analytic processing  Right hemisphere  Spatial abilities  Negative emotion  Holistic, integrative processing  Lateralization: specialization of the two hemispheres  Plasticity of the cerebral cortex  Brain plasticity: a highly plastic cerebral cortex, in which many areas are not yet committed to specific functions, has a high capacity or learning; if a part of the cortex is damaged, other parts can take over tasks it would have handled  At birth, hemispheres have already begun to specialize.  Older children and adults retain some plasticity, but less than in young children. o Sensitive periods in brain development  Appropriate stimulation is vital for brain growth  Experience-expectant growth: depends on ordinary experiences  Experience-dependent growth: additional growth resulting from specific learning experiences o Changing states of arousal  Sleep-wake pattern moves to night-day schedule during first year  By ate 2, total sleep time declines from 18 to 12 hours per day.  Sleep patterns are affected by social environment, cultural values Influences on early physical growth o Heredity o Nutrition  Breastfeeding vs. bottle-feeding  Risk of overfeeding

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Malnutrition  Marasmus: a wasted condition of the body caused by a diet low in all essential nutrients  Kwashiorkor: caused by an unbalanced diet very low in protein  Food insecurity: effects on physical growth; learning problems Learning capacities o Classical conditioning: a neutral stimulus is paired with a stimulus that leads to a reflexive response o Operant conditioning: infants act on the environment and stimuli that follow their behavior change the probability that the behavior will occur again o Habituation: a gradual reduction in the strength of a response due to repetitive stimulation  Recovery: a new stimulus - a change in the environment - causes responsiveness to return to a high level o Imitation: copying behavior of another person  Mirror neurons: neurons that fire identically when a person hears or sees an action and carries it out on her own Motor development o The sequence of motor development  Gross-motor development: crawling, standing, walking  Fine-motor development: reaching, grasping  Prereaching  Ulnar grasp: clumsy motion in which fingers close against the palm  Transferring object from hand to hand  Pincer grasp: thumb and index finger  Large individual differences in rate of motor progress o Motor skills as dynamic systems  Dynamic systems theory of motor development: mastery of motor skills involves acquiring increasingly complex systems of action; when motor skills work as a system, separate abilities blend together, each cooperating with others to produce more effective ways of exploring and controlling the environment  Mastery involves acquiring increasingly complex systems of action with each skill  Each new skill is a joint product of  Central nervous system development  The body's movement capacity  The child's goals  Environmental supports for the skill  Cultural variations in motor development  Rates and patterns of development affected by  Early movement opportunities  Environmental stimulation  Child-rearing practices Perceptual development o Hearing  4-7 months: sense of musical phrasing  6-7 months: distinguishes musical tunes based on variations in rhythmic patterns  6-8 months: screens out sounds not used in native language  6-12 months: detects sound regularities in human speech  7-9 months: begins to divide speech stream into wordlike units

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Statistical learning capacity: by analyzing the speech stream for patterns they acquire a stock of speech structures for which they will later learn meanings, long before they start to talk

Vision  Depth perception  3-4 weeks: sensitivity to motion cues  2-3 months: sensitivity to binocular depth cues  5-7 months: sensitivity to pictorial depth cues  Pattern and face perception  Birth-1 month: prefers simple facelike pattern to other stimuli  2-4 months: prefers complex facial pattern to other complex stimulus arrangements; prefers mother's detailed facial features to another woman's  3 months: distinguishes features of different faces  5-12 months: perceives emotional expressions on faces as meaningful wholes  Intermodal perception: we make sense of these running streams of light, sound, tactile, odor, and taste information, perceiving them as integrated wholes Differentiation theory: infants actively search for the invariant features of the environment those that remain stable - in a constantly changing perceptual world...