Chapter 4

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Developmental Psychologists – study physical, mental and social changes throughout the human life cycle.
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Q What is the ideal age or ages to be? Why?
Q What is the worst age or ages to be? Why?

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We are continually developing from “womb to tomb.” This chapter will look at the following issues and how they affect development
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Nature/Nurture
Genetic inheritance vs. experience
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Continuity/Stages
Is development a continual process or does it progress through stages?
Stability/Change
Do early traits persist throughout life or do we become different people as we age?
bringing up monkey

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Conception - ovary releases a mature egg, sperm enters the egg, egg and sperm nuclei fuse within 12 hours of intercourse
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Germinal Stage – 2 week period following conception
Zygote – fertilized egg, it enters into a 2 week period of rapid cell division and develops into an embryo
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Fewer than half of zygotes survive the first two weeks
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Zygote’s outer layer attaches to uterine wall, forming the placenta
Nourishment passes through the placenta

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Embryonic Stage – 2 to 8 weeks following conception
Cells inside the placenta become embryo
Embryo – developing human organism – 2 weeks after fertilization to 2 months
During this period, cells begin to differentiate – specialize in structure and function

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Fetal Stage – 2 months to Birth
Fetus – developing human organism from 9 weeks after conception to birth
6 months – organs are formed and functional, fetus is responsive to sound
Video - early development (2:55)

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Teratogens – harmful agents (such as chemicals and viruses) that can reach the embryo or fetus as it develops and cause harm.
8 to 16 weeks is the CRITICAL PERIOD for brain development. If brain development does not occur properly then irreparable damage will be done
Video- Teratogens 4:30
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Heroin addicts have children that are born addicted to heroin
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Viruses such as AIDS can be passed from mother to child
Alcohol enters the fetus via the bloodstream and could cause Fetal
Alcohol Syndrome
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FAS – results from heavy drinking by the mother during pregnancy, especially within the first 12 weeks. Physical and psychological problems may develop due to FAS (short stature, flattened nose, short eye openings, mental retardations, hyperactivity) Video- Fetal Alcohol
Syndrome 0:00 skip to 4:30

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Genetic Problems
Besides teratogens, the fetus can also be affect by certain genetic factors
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Ex. Downs Syndrome – Chromosomal abnormality – extra 21 st chromosome. Characterized by abnormal physical traits (folding of skin around the eye, wide tongue, flattened facial features, and stunted growth) and mental retardation.

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We are born with specific reflexes
Rooting Reflex – a baby’s tendency, when touched on the cheek, to open the mouth and search for food
Sucking Reflex – when an object is placed in the baby’s mouth, the baby will suck
Moro Reflex – baby flings limbs and then retracts when startled
Grasping Reflex – if an object is placed in the palm or foot pad the baby will try to grasp the object
Babinski Reflex – when the foot is stroked, a baby will curl its toes.
Stepping Reflex – baby will move one foot after another, making a stepping motion.
VideoPrimary Reflexes

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Habituation – decreasing responsiveness with repeated stimulation
Infant will lose interest in a stimulus with repeated exposure
Ex. If you watch scary movies a lot you may not feel afraid when viewing them because you’ve been habituated to scary movies.
Video – example of habituation
Video- Habituation 2:45

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Babies prefer to look at faces or face-like objects
Faces – recognizes mothers face by 3 months
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Hearing –
Hearing develops before birth
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At 1 month, an infant can recognize the mothers voice
Video- Recognizing Mother's voice
Seeing – born almost legally blind but babies can see 8-12 inches in front of them
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Touch – infant shows a number of reflexes at birth
Smell and Taste – At six weeks, infant can smell the difference between mother and stranger

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Q What is your earliest memory (not including pictures you’ve seen)
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Because we lack neural connections, many of our early memories do not exist
Average earliest memory – 3.5 years old
At the age of 4, we begin organizing our memories differently

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Maturation – biological growth processes that enable orderly changes in behavior. Maturation is relatively uninfluenced by experience
Process can be faster or slower depending on the environment
Babies roll over before they sit up, sit up before they crawl, and crawl before they walk. (Blind children do these things as well) – Nature or Nurture?
Genetics – twins begin sitting up and walking on nearly the same day.

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1. Laugh
2. Pedal a tricycle
3. Sit without support
4. Feel ashamed
5. Walk unassisted
6. Stand on one foot for 10 seconds
7. Recognize and smile at the mother and father
8. Kick a ball forward
9. Make two word sentences
10. Think about things not seen

Developmental Norms – avg. age at which children perform various skills/behaviors.
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Laugh-
Pedal a tricycle-
2 months
24 mths
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Sit without support 5-6 mths.
Feel ashamed 24 mths
Walk unassisted 12 mths
Stand on one foot for 10 seconds 4.5 yrs.
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Recognize and smile at the mother and father 4-5 months
Kick a ball forward 20 mths
Make two word sentences 24 mths
Think about things not seen 20-22 mths