1. Prenatal and Infant Development
Mr. Koch
AP Psychology
Forest Lake High School

2. Conception
A single sperm fertilizes a single ovum (egg) to create a zygote
“germinal stage” - process of rapid cell division and then differentiation
At about 10 days, attaches to wall of uterus
Outer cells form placenta, inner cells develop into embryo

3. Embryonic Stage Stage from 2-9 wks after conception
Organs begin to form and function
Develops heart, nervous system, stomach, esophagus, ovaries or testes
Develop eyes, ears, nose, jaw, mouth lips
By end have tiny arms w/ elbows, hands, fingers
Legs have knees, ankles, toes

4. Embryo at about 6 weeks: Notice the large neural tube and the formation of the heart and other internal organs.

5. Embryo at
approximately
7 weeks:
Eyes, fingers,
toes and most internal
organs have formed,
but are not yet
fully functional.

6. Fetal Stage
7 month period of prenatal development, spanning 9 weeks from conception to birth
Begins to look distinctly human
Organs grow and start to function
By 3 months: can kick, make fist, turn head, open mouth, swallow, frown
In 6th month: eyelids open, has tastebuds, well-developed grasp, can breathe regularly as long as 24 hrs. at a time
Could potentially survive premature birth by end of 6th month
Organ systems typically functional by end of 7th month
8th & 9th month: respond to light & touch, hear outside sounds
Can also learn – respond differently to sound of mother (faster heartbeat) and stranger (slower heartbeat)

7. Teratogens
Potentially harmful agents (i.e. viruses, chemicals) that can affect prenatal development
Placenta screens out most harmful substances, but these sneak through
Especially harmful if during embryonic stage
“critical period” in prenatal development
If heart, eyes, ears, hands, feet don’t appear, cannot form later – if formed incorrectly, defects are permanent
Teratogens during fetal stage affect size, behavior, intelligence, and health

9. Teratogens Disease Drugs (i.e. heroine, cocaine, crack)
Can be born with AIDS or experience physical defects from other diseases like rubella
Drugs (i.e. heroine, cocaine, crack)
Can be born addicted
“Crack babies”
premature, underweight, tense, fussy, delayed physical growth & motor development, behavior & learning problems
Smoking/nicotine
Can cause respiratory problems, irritability, social/attention problems, greater risk for nicotine addiction later in life, can harm brain development
Can cause reduction of nutrients that can lead to premature and underweight birth, which can cause cognitive and behavioral problems

10. Teratogens Alcohol Fetal Alcohol Syndrome (FAS)
Can kill fetal brain cells – depresses fetal nervous system, putting at risk for birth defects & mental retardation
Fetal Alcohol Syndrome (FAS)
Characterized by mental retardation, possible physical malformations
Behavioral and psychological problems also linked to mothers experiencing significant stress, depression, or flu in first 6 months
Fortunately, vast majority of infants (>90% in western nations) are born without mental or physical problems

11. Newborns How do we study capabilities of infants?
Very difficult – present stimuli & monitor response
Eye movements, changes in heart rates, sucking rates, brain waves, body movements, and skin conductance
Can see at birth
Blurry, but able to see large, close objects
Seem to prefer faces and seem prepared to distinguish from other visual stimuli
Born with limited hearing capabilities
Notice single note differences of tone, turn head toward sounds, particularly attuned to sounds of speech
Similar sense of smell & taste to adults, but less developed
Breast-fed infants show preference for smell of own mother to others
In general, infants’ sensory abilities seem to dispose to focus attention on caregiver

12. Newborns Born with numerous reflexes that aid survival
Involuntary, unlearned motor behaviors
Ex. “rooting” reflex, sucking, etc.
Most disappear in 3-4 months when brain development allows voluntary control of muscles and development of motor skills

13. Reflexes Rooting Sucking Swallowing Grasping Stepping
Baby turns its head toward something that brushes its cheek and gropes around with mouth
Sucking
Newborn’s tendency to suck on objects placed in the mouth
Swallowing
Enables newborn babies to swallow liquids without choking
Grasping
Close fist around anything placed in their hand
Stepping
Stepping motions made by an infant when held upright

14. Newborns Brain development
Born with overabundance of neurons, but immature (connections poorly developed)
After birth, neural networks develop rapidly until puberty when “pruning” process gains importance

15. Newborns Brain development helps enable maturation
Natural growth or change that unfolds in a fixed sequence, relatively independent of environment
Must be biologically prepared for certain changes to develop
Age of maturation will vary, but sequence rarely does
However, research shows that once properly matured, experience can impact efficiency, effectiveness of development
Once again, nature and nurture interact

16. Motor Development Developmental norms
Ages by which an average child achieves various developmental milestones
First, infants begin to roll over. Next, they sit unsupported, crawl, and finally walk.
Experience has little effect on this sequence.
OBJECTIVE 6| Outline four events in the motor development sequence from birth to toddlerhood, and evaluate the effects of maturation and experience on that sequence.

17. Maturation and Infant Memory
The earliest age of conscious memory is around 3½ years (Bauer, 2002). A 5-year-old has a sense of self and an increased long-term memory, thus organization of memory is different from 3-4 years.
OBJECTIVE 7| Explain why we have few memories of experiences during our first three years of life.
Courtesy of Carolyn Rovee-Collier
Amy Pedersen