Genes, Environment, &
Development
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4. Developmental Psychology
a. GLO’s
i.
To what extent do biological, cognitive and
sociocultural factors influence human
development
ii.
Evaluate psychological research relevant to
the study of human development
b. Cognitive Development
i.
Evaluate theories of cognitive development
ii.
Discuss how social and environmental
variables may affect cognitive development
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Behavior Genetics: Predicting Individual
Differences
Behavior Geneticists study our differences and
weigh the relative effects of heredity (nature) and
environment (nurture).
-Are there universal human behaviors?
- Of course: smiling, dancing, singing, playing,
feasting, conformity, organizing hierarchies, living
in families, crying etc.
- The key is genes, culture & experience matter
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Genes: Our Codes for Life
Chromosomes containing DNA
(deoxyribonucleic acid) are situated in the
nucleus of a cell – 23 from Mom/Dad
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Genes: Our Codes for Life
• Segments within DNA consist of genes that
make proteins to determine our development.
• Genes don’t directly guide behavior –protein
=building blocks of our phys.dev.
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- You are 99.9% similar genetically to Adolf
Hitler, Martin Luther King Jr., Jesus, Eva
Mendes, Mohammad, Genghis Khan,
Catherine the Great, and Vera Wang
- You are 99.4% similar to Nim Chimpsky in the
“functionally important” DNA sites
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Gene Variations
• Slight variations person to person…
define uniqueness and give clues to disease,
explain height differences, and why one might
be happy or depressed
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Experimental Set-up
• Design an experiment that could tease apart difs.
b/w hereditary and environment – hint: think
kids
• Subjects?
• Control group?
• Experimental group?
• Independent/dependent variables?
• Things to control for…?
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Twin Biology
Studying the effects of heredity and
environment on two sets of twins, identical
(monozygotic - MZ) and fraternal (dizygotic –
DZ), has come in handy.
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Prenatal Environment
-Identical twins who share the same placenta (b) are
more alike than those who do not (a), suggesting
prenatal influences on psychological traits – social
competence & self-control
-In (a), one might get richer blood, better virus
protection
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Separated Twins
A number of studies compared identical twins
raised separately from birth, or close
thereafter, and found numerous similarities.
Separated Twins
Personality, Intelligence
Abilities, Attitudes
Interests, Fears
Brain Waves, Heart Rate
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Separated Twins
Critics of separated twin studies note that
such similarities can be found between
strangers. Researchers point out that
differences between fraternal twins are
greater than identical twins.
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Adoption Studies
Adoption studies, as opposed to twin studies,
suggest that adoptees (who may be
biologically unrelated) tend to be different
from their adoptive parents and siblings.
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Adoptive Studies
Adoptive studies strongly point to the simple
fact that biologically related children turn out
to be different in a family. So investigators
ask:
Do siblings have differing experiences?
Do siblings, despite sharing half of their genes, have
different combinations of the other half of their genes?
Ultimate question: Does parenting have an effect?
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Developmental Psychology
Issue
Nature/Nurture
Continuity/Stages
Stability/Change
Details
How do genetic inheritance
(our nature) and experience
(the nurture we receive)
influence our behavior?
Is developmental a gradual,
continuous process or a
sequence of separate stages?
Do our early personality
traits persist through life, or
do we become different
persons as we age.
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Conception
A single sperm cell (male) penetrates the
outer coating of the egg (female) and fuses to
form one fertilized cell.
Lennart Nilsson/ Albert Bonniers Publishing Company
Lennart Nilsson/ Albert Bonniers Publishing Company
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Prenatal Development
Lennart Nilsson/ Albert Bonniers Publishing Company
Lennart Nilsson/ Albert Bonniers Publishing Company
At 9 weeks, an embryo turns into a fetus (c and
d). Teratogens are chemicals or viruses that can
enter the placenta and harm the developing
fetus.
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The Competent Newborn
Infants are born with reflexes that
aid in survival, including rooting
reflex which helps them locate
food.
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The Competent Newborn
Offspring cries are important signals for
parents to provide nourishment. In animals
and humans such cries are quickly attended
to and relieved.
Lightscapes, Inc. Corbis
Carl and Ann Purcell/ Corbis
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Cognitive Development in the Newborn
Investigators study infants becoming
habituated to objects over a period of time.
Infants pay more attention to new objects
than habituated ones, which shows they are
learning.
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Infancy and Childhood
Infancy and childhood span from birth to the
teenage years. During these years, the
individual grows physically, cognitively, and
socially.
Stage
Span
Infancy
Newborn to toddler
Childhood
Toddler to teenager
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Developing Brain
The developing brain overproduces neurons.
Peaking around 28 billion at 7 months, these
neurons are pruned to 23 billion at birth. The
greatest neuronal spurt is in the frontal lobe
enabling the individual to think rationally.
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Maturation
The development of the brain unfolds based
on genetic instructions, causing various bodily
and mental functions to occur in sequence—
standing before walking, babbling before
talking—this is called maturation.
Maturation sets the basic course of
development, while experience adjusts it.
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Motor Development
First, infants begin to roll over. Next, they sit
unsupported, crawl, and finally walk.
Experience has little effect on this sequence.
Profimedia.CZ s.r.o./ Alamy
Phototake Inc./ Alamy Images
Jim Craigmyle/ Corbis
Renee Altier for Worth Publishers
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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.
Courtesy of Carolyn Rovee-Collier
Amy Pedersen
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Principles of Cognitive LOA:
1.Mental processes guide behavior
2. The mind can be studied scientifically
(by developing theories and using
research)
3. Cognitive processes are influenced by
social and cultural factors
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Topics within Cognitive LOA
include:
-thinking
-problem solving
-memory
-perception
-emotion
-language
All of these require development
based on experience
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Schema development
• In psych, many theories support this
• Most theorize our human schemas develop
very early in life, infant cognition begins
immediately
• How we can measure it and understand more
of our experience is through ---• (drum role please…..)
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Language!
• LANGUAGE is the most fundamental of all the
cognitive processes.
• It is, after all, responsible for the development
and use of the other human cognitive
processes, such as memory and perhaps
emotion.
•
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Language
• -regulates our memory, emotion…it
allows us to transcend time – we can
discuss the past and plan the future.
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Language
• Is a cognitive process = cognitive LOA
• Is also absolutely biological & culturally
influenced (nature, nurture)
• Influences our behavior!
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Piaget’s Theory and Current Thinking
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Cognitive Development
Piaget believed that the driving force behind
intellectual development is our biological
development amidst experiences with the
environment. Our cognitive development is shaped
by the errors we make.
Both photos: Courtesy of Judy DeLoache
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Sensorimotor Stage: Criticisms
Children can count. Wynn (1992, 2000)
showed that children stared longer at the
wrong number of objects than the right ones.
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Preoperational Stage: Criticism
DeLoache (1987) showed that children
as young as 3 years of age are able to
use mental operations. When shown a
model of a dog’s hiding place behind
the couch, a 2½-year-old could not
locate the stuffed dog in an actual
room, but the 3-year-old did.
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That said…
• Piaget is fun but a bit outdated
• Two more modern theorists of cognitive
development – Lev Vygotsky and Jerome
Bruner flip Piaget on his head
• They argue that it is cognitive development
that drives brain maturation
• Also, both include a cultural component that
Piaget neglected
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Cultural Framework for Cognition
• Narratives – how would you define these?
– Something along the lines of special kinds of stories
that help us understand how one operates within a
culture
• Norms – how would you define these?
– Something along the lines of acceptable behaviors or
expectations/demands of a particular culture
– Narratives help us acquire norms
• Cultural Acquisition Device(s) or CAD’s
– Biologically based etics that include narratives & “are
universal tools of meaning making” (Miller et. al.,
2007)
• How does all this fit in with children’s dev. of
language?
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Social & Environmental Variables in
Cognitive Dev.
• Poverty – nutrition, home
life, parenting,
neighborhoods, high
crime/unemployment,
etc.
• Undernourishment –
lower birth weight,
stunted growth, less
physically active, less
interest in environment &
less emotional expression
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Soc. Env. Variables in Cog. Dev.
• Education – 1/3 of low income kids are behind
peers in Kindergarten
• By 4th grade 50% are not reading proficient
according to the National Center for Children in
Poverty (2002)
• Poor kids less likely to be labeled gifted & do
extracurriculars, more likely to repeat a year, have
LD’s and learning delays
• Head Start and Begindergarten have not been
shown to help
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Summation
• The link between poverty and lower cognitive
development is clear, but it seems to be a
cumulative effect of factors
• Cumulative positive and negative factors have
similar effect on kids of privilege
• So again – what can we do?
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