The First Two Years: Biosocial Development Charles A. Guigno, M.A.

Brain Growth Head-sparing Biological mechanism Brain is the last part of the body to be damaged by malnutrition. Protects the brain when malnutrition disrupts body growth. Neurons Connecting Communication within the central nervous system, brain and spinal cord, begins with nerve cells called neurons. The newborn brain has billions of neurons, 70% of them in the cortex. Most thinking, feeling and sensing occur in the cortex.

Brain Development (c) 2012 The McGraw-Hill Companies, Inc.

The Developing Cortex

Brain Development: Dendrites Sprouting

Experience and Pruning At birth the brain contains at least 100 billion neurons, more than a person needs. 40,000 new synapses are formed every second in the infant’s brain. Brain structure and growth depends on genes and maturation, but even more on experience. Transient exuberance: the great but temporary increase in the number of dendrites that develop in an infant’s brain during the first two years of life. Expansion and pruning of dendrites occur for every aspect of early experience. Unused dendrites whither to allow space between neurons, allowing more synapses and thus more complex thinking.

Experience and Pruning (Ct’d) Brain sculpting is attuned to experience: the appropriate links in the brain need to be established, protected and strengthened while inappropriate ones are eliminated. Some research suggests that infants who are often hungry, hurt or neglected may develop brains that compensate and cannot be reprogrammed even if circumstances change. The hungry baby becomes the obese adult The abused child rejects attention

Harm and Protection Infants need stimulation Experience-dependent: brain development is variable because circumstances vary. Experience-expectant: brain development occurs because of circumstances that all human babies should have. Sensory stimulation: play, sights, sounds, touches and movements all help with brain connections. Infants are fascinated by simple objects and facial expressions.

Harm and Protection (Ct’d) Infants need protection Shaken baby syndrome: a life-threatening injury that occurs when an infant is forcefully shaken back and forth, this motion ruptures blood vessels in the brain and breaks neural connections. Stress and the brain Overabundance of stress hormones damages later brain functioning. Self-righting: an inborn drive to remedy a developmental deficit Infants with no toys develop their brains using other objects available. Human brains are designed to grow and adapt.

Sleep Sleep specifics vary because of biology and the social environment. Newborns sleep about hours a day, in one to three-hour segments. Newborns’ sleep is primarily active sleep. Newborns have a high proportion of REM (rapid eye movement) sleep. Closed lids, flickering eyes and rapid brain waves. Indicates dreaming.

Sleep Problems First born infants typically receive more attention and this may contribute to sleep problems. One fourth of parents of children under age three reported sleep problems. Parent reactions to infant sleep shape the baby’s sleep patterns, which in turn affect the parents.

Perceiving and Moving Sensation precedes perception. Perception leads to cognition. Sensation: Response of a sensory system (eyes, ears, skin, tongue and nose) when it detects a stimulus. Every sense functions at birth. Young babies use their senses to attend to everything without judgment. Survival requires babies to respond to people. Perception: mental processing of sensory information when the brain interprets a sensation. If a sensation occurs often, it connects with past experience, making a particular sight worth interpreting

Hearing and Seeing Hearing Develops during the last trimester of pregnancy Most advanced of the newborn’s senses Speech perception by 4 months after birth. Seeing Least mature sense at birth Newborns focus between 4-30 inches away Experience and maturation of the visual cortex improve shape recognition, visual scanning and details. Binocular vision at 3 months.

Tasting and Smelling Function at birth and rapidly adapt to the social world. Related to family and cultural preferences. May have evolutionary function. As babies learn to recognize each person’s scent, they prefer to sleep next to their caregivers.

Touch and Pain Touch Sense of touch is acute in infants. Wrapping, rubbing, massaging and cradling are soothing to many new babies. Pain Pain and temperature are often connected to touch. Some people assume that even the fetus can feel pain. Others say that the sense of pain does not mature until months or years later.

Motor Skills: Gross Motor Skills Motor skill: the learned abilities to move some part of the body, in actions ranging from a large leap to a flicker of the eyelid. Course of development Cephalocaudal (head-down) and proximodistal (center-out) direction. Gross motor skills Physical abilities involving large body movements (walking and jumping)

Dynamic Systems: Motor Skills Muscle Strength: As they gain strength they can stand and then walk. Brain Maturation: As the brain matures, deliberate leg action becomes possible. Practice: Unbalanced, wide-legged, short strides become a steady, smooth gait. Powerfully affected by caregiving before the first independent step.

Motor Skills: Fine Motor Skills Fine motor skills: physical abilities involving small body movements, especially of the hands and fingers. (mouth movements too) Shaped by culture and opportunity By 6 months: most babies can reach, grab and grasp almost any object of the right size. Towards the end of the first year and throughout the second year: babies master the pincer movement and self-feeding.

Surviving in Good Health At least 9 billion children were born between 1950 and 2010; more than 1 billion of them died before age 5. The world death rate in the first five years of life has dropped about 2 percent per year since Public health measures (clean water, nourishing food, immunization, medical treatments)

Sudden Infant Death Syndrome Sudden infant death syndrome (SIDS) Situation in which a seemingly healthy infant, usually between 2 and 6 months old, suddenly stops breathing and dies unexpectedly while asleep. Beal: Studied SIDS death in South Australia and concluded factors related to increased risk Low birth weight Sleeping position (Back is best!) Maternal smoking Bedding type