human development – the study of the human over the life span genes – our biological blueprints...
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HUMAN DEVELOPMENT
Human development – the study of the human over the life span
Genes – our biological blueprints
Many of our characteristics are determined at the moment of conception, when 23 chromosomes on the egg pair up with 23 chromosomes on spermGenotype – all information stored in genesPhenotype – observable characteristics
The likelihood of traits being expressed can be worked out with a Punnett Square
Chromosomes contain DNA, which is made up of 1,000s of genes (total of ~100,000)•Each gene is a self-replicating segment of DNA capable of synthesizing proteins
•Genes are composed of NUCLEOTIDES – a linear sequence of structural units that form DNA – these biochemical bases combine to form 3 billion pairs that determine your individual biological development
The nucleotide base letters are:•A adenine•C cytosine•G guanine•T thymine
Some Genetic Abnormalties:
1. Turner’s Syndrome – X - karyotype
Sterile, limited secondary sex characteristics, short “webbed” neck 1 in 2,500 live births
2. Klinefelter’s Syndrome – XXY karyotype
Sterile, tall, small testicles, passive, reclusive 1 in 1,000 live births
3. Jacob’s Syndrome – XYY karyotype
Tall, lower mental ability, high level of testosterone1 in 1,000 live births
4. Super female – XXX karyotype
No specific abnormalities 1 in 1,000 live births
Webbed neck
5. Edward’s Syndrome – Trisomy of 18th chromosomeSevere mental retardation, most die in infancy6. Down Syndrome – Trisomy of 21st
chromosomeMocaism – some do not have the abnormality in every chromosome; affects level of mental retardation and expression of characteristics
WHO ARE THE PERFECT SUBJECTS FOR STUDYING HUMAN DEVELOPMENT?
•Identical twins
HOW DOES PSYCHOLOGY STUDY HUMAN DEVELOPMENT?
•Twin studies, adoption studies, temperament research, heritability studies
Monozygotic twins: Dizygotic twins:
Twin studies show remarkable similarities in intelligence, temperament, stress response and rates of mental illness**Most ideal twins? Identical twins separated at birth – offer both nature and nurture opportunity for study
3 major issues researched by developmental psychologists:
1. Nature vs. nurture2. Stability vs. change3. Continuity vs. stages
PRENATAL DEVELOPMENT:
•Female is born with 500,000 O ocytes – cells with potential to develop into ovum. 10,000 remain at puberty and approx. 400 will be ovulated in a lifetime•Male begins producing sperm at puberty, and produces it for the rest of his life
One ejaculation contains 200 to 400 million sperm!!The odds against you being you are billions to one!
When is a female most fertile and likely to conceive?
**14 days from the start of her last period
Conception occurs! Newly fertilized cell is called a zygote
Stages of Prenatal Development:
1. Germinal Period – Conception through 14th day•Ends when zygote implants into the
wall of uterus (or cells are sloughed off)
2. Embryonic Period – 2nd through 8th week
Development is cephalo-caudal (from the head to the trunk)
Critical period of pregnancy (though entire pregnancy is important) – time when environment can have the greatest effect on the organism
6 week embryo
3. Fetal Period – 9th through 40 weeks 20 week fetus
Development shifts to Proximo-distal (from trunk outward to limbs)
Teratogen – agent that can cause damage to embryo/fetusMost infamous teratogen:thalidomide
Age of viability – time when fetus has a 50 – 50 chance of survival if premature: 24 weeks
24 week premie
THE NEWBORN:
Reflexes: sucking
rooting
grasping
stepping
Babinsky
Moro
Infant intelligence:
Recognize mother’s voice
Recognize mother’s milk
Prefer faces to patterns
Imitate facial expressions at 2 weeks
Physical Development:
Motor milestones of the first 2 years:
1-2 weeks Turns head to follow moving object6 weeks Rolls from stomach to back3 months Rolls from back to stomach6-7 months Sits alone for 1 minute8-9 months Crawls10 months Says da da8-10 months Walks while holding on to something12 months Takes first steps14 months Walks alone, says several words18 months Climbs stairs, says many words18-24 months Runs, combines two words24 months Puts on shoes
**All require biological maturation
Cognitive Development:
Jean Piaget’s Theory of Cognitive Development
Child develops thinking abilities through stages as their SCHEMAs grow and change
Schema – framework for organizing information
•New information fits easily into schema sometimes - assimilation•New information requires a change of the schema - accomodation
1. Sensorimotor Stage – 0 to age 2
Babies understand their world through their senses and motor activities
Abilities they develop:
* Object permanence – an understanding that objects exist when no longer visible
* Stranger anxiety
* Language develops
•All take place at age 8-9 months
2. Preoperational stage – ages 2 through 6
The child is EGOCENTRIC – cannot take another person’s point of view
The preoperational child loves to :pretenduse animismuse artificialism
3. Concrete Operations 7 - 12
The school aged child now uses LOGIC
•Egocentrism, animism and artificialism break down•Concrete (not abstract) types of activities such as multiplication and division are possible
•Conservation – the understanding that quantity remains the same regardless of shape
•The concrete operations child rejects the magical beliefs in Santa, tooth fairy, etc.
4. Formal Operations 13 and up•The child can now use ABSTRACT reasoning
•Abstract math and science are possible
•Interest in world affairs, religion and politics increase
**Critics of Piaget say all of the ages in the stages should begin earlier**
Self-concept Development
Babies recognize themselves by 15 months
Social Development
ATTACHMENT – intense infant love for caregiver
It lies at the heart of the nature vs. nurture issue
•Studied by Harry Harlow
•Baby rhesus monkeys were raised in individual cages, away from mother with fabric for a blanket
•They were distressed when he took the fabric out to wash it; he thought about what it meant
•It made him question the conventional idea that babies attach to mothers because they provide food
He created surrogate figures: one covered in cloth, the other with a bottle
The babies became very attached to the cloth-covered figure
He called this need for soft, loving contact CONTACT COMFORT
Good news for dad – he can provide contact comfort too!
Another key to attachment: familiarity
Konrad Lorenz discovered a rigid attachment process in animals:
•The bird followed him like he was the mother
•He made himself the first thing baby geese or ducks saw after hatching
IMPRINTING
He also identified a critical period for imprinting
Mary Ainsworth studied mothers and toddlers - mothers left toddlers in room for a few minutes, how did child respond?
Parenting styles and attachment:
She identified 3 types of attachment:
1. Securely attached – child explored around mom, cried when mom left, joyous when she returned2. Insecurely attached – child was clingy, cried when mom left, angry when she returned
3. Avoidant – little contact between mother and child
Could this foretell the relationship patterns of a lifetime??