AP Psychology
Developmental Psychology (7-9%): Prenatal &Infancy

Weiten Ch 11

Myers Ch 5

Notes Outline

  1. Prenatal development
  2. Environmental Factors in Prenatal Development
  3. Infancy & Childhood Developmental Norms
    • Norms
    • Motor Development
    • Temperament
    • Attachment
    • Personality

Prenatal Development

Conception --> Birth (~ 9 months or 40 weeks)

  1. Sperm meets egg and creates a ZYGOTE –one-celled organism that is the beginning of life

2. GERMINAL STAGE – first phase of prenatal development – first two weeks after conception. Mass of rapidly multiplying cells moves along fallopian tube to the uterus to implant. If implantation occurs then a PLACENTA is created – allows oxygen and nutrients to flow in and bodily wastes out.

3.  EMBRYONIC STAGE – second phase – end of two weeks till end of second month. Most vital organs and systems are created, heart, spine, & brain emerge, and cells begin to specialize. This is the stage where most miscarriages occur.

4.  FETAL STAGE – third phase – lasts from 2 months till birth. Muscles and bones form, organs finalize and begin to function. At about 23-26 weeks the fetus reaches the THRESHOLD OF VIABILITY where it is possible (but not guaranteed) to live outside the mothers body (75% at 26 weeks).

Environmental Factors in Prenatal Development

Fetus and mother are connected through the placenta, so when she is sick, or ingests chemicals it is passed onto the baby.

TERATOGENS are any external agent that can harm a embryo or fetus.

  • Drug use – Recreational and medicinal drugs are passed onto the fetus, and can result in birth complications, congenital defects, addiction, or death of the fetus.
  • FETAL ALCOHOL SYNDROME is a collection of congenital problems as a result of maternal alcohol use during pregnancy (microencephaly, heart defects, irritability, hyperactivity, delayed mental and motor development, mental retardation, deficits of IQ, increased impulsive, antisocial, and delinquent behavior)
  • TOBACCO USE – increases risk of miscarriage, stillbirth, prematurity, and sudden infant death syndrome (SIDS), slower than average cognitive development, attention deficits, hyperactivity
  • Maternal Nutrition – malnutrition puts a fetus at risk, but hard to define causal relation because of confounding variables such as poverty, drug use, and limited access to healthcare.
  • Maternal stress – anxiety, depression, & stress can all upset hormonal balance and interfere with development of fetus.

Infancy & Childhood

MATURATION – development that reflects the gradual unfolding of your genetic blueprint

Developmental norms – indicate the MEDIAN age at which individuals display various behaviors (11.3 chart on p 438)

1. Motor development – progression of muscular coordination required for physical activities

  • Cephalocaudal trend – head to food direction of motor development
  • Proximodistal trend – center-outward direction of motor development, torso before extremities, twist whole body to reach something then just use arm

2.  Temperament – Thomas & Chess longitudinal study of temperament, temperament at 3 months was a good indicator of 10 yo

  • Easy – 40%
  • Slow-to-warm up – 15%
  • Difficult – 10%
  • Mix of those 35%

3.  Attachment – close, emotional bonds of affection that develop between infants and caregivers. NOT INSTANT, takes 2-3 months.

  • SEPARATION ANXIETY begins to occur between 6-8 months, emotional distress when they are separated from people with whom they have formed an attachment
  • Attachment is influenced by mothers behavior AND temperament of baby
  • Attachment strongly influenced relationships and temperament later in life. The more secure the attachment, the more resilient, sociable, and higher self-esteem a person will have later in life. à BASED ON WORKING MODELS infants create in their heads of the dynamics of relationships à caregivers function as a “secure base” that they work from.


  • Harlow & his monkeys – took infant rhesus monkeys and gave them substitute “mothers”, one made of wire that fed the monkeys and one made of terrycloth that did not feed them. Monkeys preferred the more comforting terrycloth “mother”
  • Bowlby – influenced by Harlow and evolutionary theory postulated that there was a biological basis for attachment. Babies are programmed to emit behavior that prompts protective response from adults, adults are programed to like babies and want to care for them.
  • Ainsworth – influenced by Harlow & Bowlby used experiments to measure and categorize types of attachment using STRANGE SITUATION PROCEDURE
  • Secure attachment – Predominant type of attachment - infants use mother as a home base, explore the world from there. Upset quickly when mother leaves, calms quickly when she returns
  • Anxious-ambivalent attachment (resistant) – anxious even when mother is there, excessively upset when she leaves, not comforted when she returns
  • Avoidant attachment – seek little contact, not upset when mother leaves, not comforted when she returns.
  • Disorganized-disoriented attachment – Added later, children confused as to whether or not mother is comforting, are especially insecure