Prenatal Development and the Newborn

• At 8 weeks after conception, babies are anatomically indistinguishable; 4/5th month different
• Sex determined by 23rd pair of chromosome
• X chromosome: comes from either mother or father; females have two, males have one
• Y chromosome: comes from father, paired with x to form male
• Y chromosome stimulates development of male sex organ by producing testosterone: most important male sex hormone, but females have it too
• Gender: biologically or socially influenced characteristics which people define as male/female
• zygotes: fertilized eggs; less than half survive pass 2 weeks
• after 10 days, zygote attach to mother’s uterine wall and forms placenta for nourishment, zygote becomes embryo:
• developing human from 2 weeks to second month
• after two months, looks human, called fetus: developing human from 2 months to birth
• fetus hears muffled version of mother’s voice and prefers it after birth
• harm can come when placenta gets teratogens: agents that can harm embryo/fetus during prenatal stage; a mother who is a heroin addict will have a heroin addicted baby
• newborns are equipped with reflexes ideal to survival
• rooting reflex: reflex, when touched on cheek, to open mouth and find nipple
• perceptual abilities continue to develop during first month, can distinguish mother’s odour

 
Infancy and Childhood

• maturation: biological growth processes that enable orderly change in behaviour, could be influenced by experiences
• maturation sets the basic course of development and experience adjust it
• lack of neuron connections reason why earliest memories rarely earlier than third birthday (experiences help develop neural connections)
• Rosenzweig and Krech reared some young rats in solitary confinement and others in playground; found those in playground develop thicker and heavier brain cortex
• For optimum development, early years critical –use it or lose it; but development exists through life as neural tissues changes –experiences nurture nature
• plasticity: brain ability to reoganize pathways to compensate damage; if laser damaged spot in cat’s eye, brain area receiving input from spot will start responding to stimulation from nearby areas in eye;  brain hardware changes with time –can rewired with new synapses
• children brains most “plastic” –surplus of neurons
• when neurons are destroyed, nearby ones may partly compensate by making new connections
• experience influences motor behaviour
• experience(nurture) before biological development(nature) has limited effect

 
Cognitive Development

• Cognition: mental activities associated with knowing, thinking, & remembering
• Piaget believed child’s mind develops through series of stages
• Piaget believed children built schemas: concept or framework that organises and interprets info; mental molds into which we pour our experience
• assimilate: interpreting new experience in terms of existing schemas; given schema for dog, child may call 4-legged animals doggies
• to fit new experiences, we accommodate: adapting one’s schemas to incorporate new info; child realises doggies schemas too broad and refines category

 
Piaget’s 4 stages of Cognitive Development

1.    Sensorimotor Stage (Birth – 2 years old)

• Infants know world in terms of sensory impressions and motor activities
• Lack objective permanence: awareness that things continue to exist when not perceived; Baby believes toy only exists when it is starring at it

2.    Preoperational Stage (preschool – 6/7 years old)

• Child learns to use language, but aren’t able to comprehend mental operations of concrete logic; lacks conservation: principle that quantity remains the same despite changes in shape; water from tall, thin glass poured into wide, flat glass would be the same
• Children are egocentric: inability to see another’s point of view

3.    Concrete Operational Stage (6/7 – 11 years old)

• Children gain mental operations that enable logical thinking about concrete events; understands conservation and mathematical transformation (reversing arithmetic operations)

4.    Formal Operational Stage (12 years -life)

• Reasoning expands from concrete (involving actual experiences) to abstract thinking (involving imagined realities and symbols)
• Children able to solve hypothetical situations and its consequences
• researchers believe development more continuous than did Piaget

 
Social Development

• infants develop intense bond with those who care for them; prefers familiar faces and voices
• after object permanence, develop stranger anxiety: fear of strangers commonly displayed after 8 months of age
• attachment: emotional tie with another person; shown by child seeking closeness to caregiver (those who are comfortable, familiar, and responsive to needs) and distress when seperated
• psychologists use to believe attachment through need for nourishment, but now consider wrong
• Harlow’s Monkey Studies: Harry Harlow bred monkeys of which he separates from mothers shortly after birth; in cages were a cheesecloth baby blanket; baby monkeys formed intense attachment to blanket –distressed when taken away; later, Harlow created 2 artificial mothers (“Harlow’s Mothers”), one bare wire cylinder with wooden head, other a cylinder wrapped with terry cloth; when reared with nourishing wire mother and nonnourishing cloth mother, monkeys preferred cloth mother; concluded body contact more important than nourishment
• Critical period: an optimal period shortly after birth when organism’s exposure to certain stimuli/experience produces proper development; first moving object a duckling sees is mother, then follows only it
• Developmental psychologists believe humans don’t have precise critical period
• Imprinting: process by which certain animals form attachment during critical period; humans don’t imprint, but becomes attached to “known”
• Temperament: person’s characteristic emotional reactivity and intensity;  temperaments endure; ex. easy-going, quiet, placid
• Heredity predispose human differences; anxious infants have high heart rates and reactive nervous system;  identical twins more likely to have similar temperaments than nonidentical
• Sensitive, responsive mothers have infants who are securely attached while the opposite (attend only when felt like doing and ignores at other times) have infants who are insecurely attached
• Anxiety over separation from parents peak at 13 months and gradually declines after
• Erik Erikson claims securely attached children approach life with sense of basic trust: sense that the world is predictable and trustworthy
• Deprivation of attachment causes withdraw, fear, and other negative consequences; most abusive parents have been neglected/battered as children
• Many developmentalists believe quality infant day care doesn’t hinder secure attachement
• Divorces place children at increased risk for developing social, psychological, behavioral, and academic problems
• By age 12, most children develop  self concept: sense of one’s identity and personal worth
• Children’s views of themselves affect actions; positive self-concept produces confidence, independence, optimism

Child-Rearing Practices

• Authoritarian parents: imposes rules and expect obedience; Why? Because I said so!
• Authoritative parents: demanding, yet responsive; exert control by both setting rules and explaining reasons; encourages open discussion and allowing exceptions when making rules
• Permissive parents: submit to children’s desires, make few demands, and use little punishment
• Rejecting-neglecting parents: disengaged –expect little and invest little
• Children of authoritative parents have the highest self-esteem, self-reliance, and social competence
• Authoritative parenting seems to give children greatest sense of control which yields motivation and self-confidence

Gender

• Gender identity: one’s sense of being male or female
• Gender-typing: acquisition of a traditional masculine or feminine role
• Social learning theory: theory that one learns social behavior by observing and imitating and by being rewarded/punished;  Mother tells daughter that she is being “a good mommy” to her doll
• Gender schema theory: theory that children learn from their cultures a concept of what a male/female is and adjust their behavior accordingly
• Genes and experiences intertwine; we are the product of  interactions between our genetic predispositions and our surrounding environments

 
Bibliography

Myers, David G., Psychology Fifth Edition. Worth Publishers, Inc. New York, NY ©1998