1. Chapter 3 Developing Through the Life Span
Prenatal development and
the competent newborn

2. Developmental Psychology
3 issues are important to developmental psychologists:
Nature and nurture
continuity
Stability and change
Developmental Psychologists study the life cycle, from conception to death.
They look at how we develop physically, cognitively, and socially.

3. The Nature of Nurture
Heredity: Genetic transfer of characteristics from parents to offspring
Genome: Complete instructions for making an organism, consisting of all the genetic material in that organism’s chromosomes
Parents everywhere wonder: Will my baby grow up to be peaceful or aggressive? Homely or attractive? Successful or struggling at every step? What comes built in, and what is nurtured—and how?
Research reveals that nature and nurture together shape our development—every step of the way.

4. Genetics
Genes are DNA segments that, when expressed (turned on), direct the production of proteins and influence our individual biological development.
Contained in the nucleus of each cell in your body are chromosomes. Each chromosome contains a coiled chain of the molecule DNA. Genes are DNA segments that, when expressed (turned on), direct the production of proteins and influence our individual biological development.

5. Environment & Gene Expression
life experiences lay down epigenetic marks, which are often organic molecules
These molecules can block the expression of any gene in the DNA segment they affect
Epigenetics explores the nature–nurture meeting place and studies how the environment can cause genes to be either active (expressed) or inactive (not expressed)
Epigenetics - the study of environmental influences on gene expression that occur without a DNA change.

6. Conception Woman: releases a mature egg at ovulation
Man: 200+ million sperm are deposited during intercourse
within a few hours, the egg’s nucleus fuses with the sperm’s nucleus
At birth, the woman has all of the eggs she will need for life… the man, however, will produce sperm continually from puberty, 24/7 at a rate of 1000/second!
The woman’s egg: 85,000x the size of a single sperm
The sperm releases enzymes to help it break through the egg’s wall
The egg, meanwhile, blocks out all other sperm while sending out feelers to pull in the “winning sperm”

7. Prenatal Development Zygote – fertilized eggs
After 10 days: the cells attach to mother’s uterine wall
This forms the placenta – it passes nourishment to the embryo
Embryo: after 2 weeks; has a noticeable heartbeat & red blood cells
For the next 6 weeks: organs, spinal development, arm/leg growth, proportions change
Fetus: after 9 weeks, embryo has taken on human characteristics
For ZYGOTE: Fewer than ½ of these survive past the first two weeks post-conception.
Week 1: cells in the zygote split until there are about 100 cells (7 divisions). After this, the cells begin to differentiate (to specialize in structure and function). This specialization is directed by your genes.

8. Prenatal Development
zygote
embryo
fetus

11. Lennart Nillson Photography
24 days
no skeleton
heart beat: day 18

12. Lennart Nillson Photography
5 weeks / 9mm
face begins to form

13. Lennart Nillson Photography
40 days

14. Lennart Nillson Photography
8 weeks

15. Lennart Nillson Photography
10 weeks

16. Lennart Nillson Photography
16 weeks
hands explore the body

17. Lennart Nillson Photography
18 weeks / 14 cm
perceive sound from outside world

18. Lennart Nillson Photography
26 weeks

19. Lennart Nillson Photography
6 months

20. Threats to the Fetus
Harm can come to the fetus when the placenta admits teratogens: agents that can harm embryo/fetus during prenatal stage.
Drug addictions
AIDS virus
nicotine / air pollution
prescription drugs
alcohol

21. Fetal Alcohol Syndrome
There is no known safe amount of alcohol for a mother to drink while pregnant.
Alcohol depresses activity in both mother and fetus’ central nervous systems.
Fetal Alcohol Syndrome (FAS)
Physical and mental abnormalities in children caused by a pregnant woman’s heavy drinking
In severe cases, signs include a small, out-of- proportion head and abnormal facial features

22. The Competent Newborn automatic reflex responses that support survival
Cries to elicit help and comfort
Searches for sights and sounds linked to other humans, especially the mother
Smells and sees well and uses sensory equipment to learn
Has a biologically rooted temperament
We have learned that babies are more aware than previously thought:
study this via habituation
we look towards human voices
we gaze longer at a face-like image
we prefer to look at objects 8-12” away (same distance to mother’s eyes while feeding)
perceptual abilities continue to develop during first month
can distinguish mother’s odour
mother’s voices encourage more voracious sucking on a pacifier

23. Reflexes rooting reflex:
trigger: a gentle stroke on the newborn’s cheek
response: baby turns toward the touch, mouth open
duration: until baby is 3-4 mo. old
reason: helps baby find food

24. Reflexes Moro reflex (startle reflex):
baby cries and extends legs, arms, fingers, arches back, then retracts arms and legs
duration: until baby is 4-6 mo. old
reason: baby’s first attempts to protect self from harm

25. Reflexes Walking reflex:
trigger: hold baby upright with feet on a flat surface
response: baby lifts one foot, then the other as if walking
duration: about 2 mo.
reason: may prepare baby developmentally for walking later on

26. Newborns prefer faces
When shown these two images with the same three elements, newborns spent nearly twice as long looking at the face-like image on the left
Newborns—average age just 53 minutes in one study—seem to have an inborn preference for looking toward faces