Class Notes – Lecture 2 – Chapter 1 continued & Chapter 2
A. The Scientific Method
An approach to testing beliefs that involves:
Choosing a question
Formulating a hypothesis
(i.e., an educated guess)
Testing the hypothesis
Drawing a conclusion
Importance of Appropriate Measurement
- Relevance to hypotheses
Reliability and Validity
Is a particular test a good measure of development?
Must be both reliable and valid to
Reliability: does test given consistent outcome each time?
Validity: does test really measure what it purports to measure?
Some measure may be reliable one time but not other
How you test validity? Most part is what u believe in
Reliability and Validity
Extent to which a test accurately reflects what it is intended to measure
Validity = reliability
Reliability ≠ validity
Ex. Intelligence and a tape measure
The degree to which independent measurements of a given behavior are
Interrater reliability: The amount of agreement in the observations of
different raters who witness the same behavior. quality
Test-retest reliability: Attained when measures of performance are similar
on two or more occasions quantity
Refers to the degree to which a test or experiment measures what it is intended to
Researchers strive for two types of validity:
Internal validity is the degree to which effects observed within
experiments can be attributed to the variables that the researcher intentionally
manipulated. --> being able to say that the outcome is because of the manipulation
that I did.
High internal validity: the researcher has control the experiment as much as
Test scores: those who studied more get more mark, this is low internal
validity unless the experimenter control other factors that might affect the
mark ex. Motivation level, gender, etc
External validity: is the degree to which results can be generalized beyond
the particulars of the research.
Questions of Interest
B. Contexts for gathering Data about Children
Structured interview: A research procedure in which all participants are asked to
answer the same questions. try not to deviate from script, more general knowledge
Clinical interview: A procedure in which questions are adjusted in accord with the
answers the interviewee provides detailed knowledge, the interviewer will deviate
from the script questioned
Caveat: Although interviews yield a great deal of data quite quickly and can
provide in-depth information about individual children, the answers to interview
questions are often biased.
2. Naturalistic observation
Observe situation without intervening
Examine how events/behaviors unfold in a natural setting
Pepler & Craig (1995) bullying in the school yard
Problem with naturalistic observation naturally occurring contexts vary on
many dimensions; many behavior occur only occasionally in the everyday environment.\
Takes longer to observe the desired question that’s wanted to be observed
3. Structured observation
Exposure to a setting that might cue behavior in question compliance of
children with parents. boys are more likely to be distracted and less compliant than
There are so many variables to answer the why
2 Naturalistic Observation
Used when the primary goal of research is to describe how children behave
in their usual environments
Because naturally occurring contexts vary on many dimensions, it is often
hard to know which ones influenced the behavior of interest.
Also, many behaviors occur only occasionally in everyday environments,
and so researchers’ opportunities to study them through naturalistic
observation are reduced.
Observer influence (biased?)
- Involves presenting an identical situation to a number of children and recording
each child’s behavior, enabling direct comparisons of different children’s behavior
and making it possible to establish the generality of behavior across different tasks
Does not provide as much information about children’s subjective
experiences and does not provide as natural a situation.
Contexts for Gatherin.g Data
C. Correlational & Causation
The primary goal of studies that use correlational designs is to determine how
variables are related to one another.
A correlation is the association between two variables.
The direction and strength of a correlation is measured by a statistic called
the correlation coefficient.
Correlation Scatterplot (cont’d) positive correlation independent variable increase, dep
variable also increase. Ex. R= 0.9
Correlation Scatterplot (cont’d) negative correlation ind incr, dep dec. ex. R= -0.9
Correlation ≠ Causation!
It is not possible to tell from a correlation which variable is the cause and
which is the effect.
3 Third-variable problem
A correlation between two variables may arise from both being influenced by some third
• Third variable problem
•If A and B are correlated: A can cause B or B cause A, or can have C,
which can be a potential factor problem
If you can measure it, you can study it
No cause and effect
“Correlation does not equal causation”
Two variables that are correlated
Variable A = use of air conditioning
Variable B = consumption of ice cream
Variable A = size of feet
Variable B = spelling ability
Allow inferences about causes and effects
Rely on random assignment, a procedure in which each child has an equal chance
of being assigned to any group within an experiment
Experimental control refers to the ability of the researcher to determine the
specific experiences that children have during the course of an experiment.
Children in the experimental group receive an experience of interest, the
Those in the control group do not receive this experience.
The dependent variable is a behavior that is hypothesized to be affected by
the independent variable.
4 Aggression & TV Viewing Study
Leibert & Baron (1972)
Hypothesis: Children more willing to hurt another child after viewing
136 Boys and Girls (5 - 9 yrs old)
Experimental group: viewed violent episodes
Control group: viewed non-violent episodes
Aggression & TV Viewing Study (cont’d)
Leibert & Baron (1972) (cont’d)
Children to play with imaginary “child” in an adjoining room
Given “hurt” or “help” option
Measured how long and how often pressed “hurt”
IV? low, didn’t consider other possible factors
EV? this would really be depended on your value system
Results experimental group pressed hurt button more often and longer
exposure to TV can cause interpersonal aggression.
Looks like an experiment BUT
No random assignment
No experimental control
Advantages natural groups that form can be great of interest
Disadvantages there might not be ethical reasons that the group was formed,
can’t make cause and effect inferences because it’s not an experiment, there’s no random
D. Designs for Examining Development
1. Cross-Sectional Designs
Children of different ages are compared on a given behavior or
characteristic over a short period of time
2. Longitudinal Designs
- Used when the same children are studied twice or more over a substantial period
problem: kids drop out or move, they didn’t stay in the study
5 3. Microgenetic Designs
Used to provide an in-depth depiction of processes that produce change
In this approach, children who are thought to be on the verge of an important
developmental change are provided with heightened exposure to the type of
experience that is believed to produce the change and are studied intensely while
their behavior is in transition.
bombard the child with different math questions count the numbers 1,2,3,4,
… or just add
Used only when we are looking for something
Comparison of Designs – table 1.6
E. Ethical Issues in Child-Development Research
Researchers have a vital responsibility to anticipate potential risks that the
children in their studies may encounter, to minimize such risks, and to make sure that the
benefits of the research outweigh the potential harm.
First ask the parent, if parents agree upon, they start experiment, but if the
children say no, experiment will stop immediately, children has the right to
Chapter 2 Prenatal Development and the Newborn Period
I. Prenatal Development
II. The Newborn Infant
I. Prenatal Development
B. Developmental Processes
C. Early Development
D. Fetal Behavior
E. Fetal Experience
F. Fetal Learning
G. Hazards to Prenatal Development
6 A Conception
Results from the union of two gametes, the egg and the sperm
Gametes are produced through a specialized cell division, which results in each
gamete’s having only half the genetic material of all other normal cells in the body.
Father’s sperm + mother’s ovum Zygote
• 46 chromosomes total
• 23 from each parent
The fertilized egg, or zygote, has a full complement of human genetic material,
half from each parent.
Marks the beginning of the three periods of prenatal development
B. Developmental Processes
Four major developmental processes transform a zygote into an embryo and
then into a fetus.
1. Cell division results in the proliferation of cells.
2. Cell migration is the movement of cells from their point of origin to somewhere
else in the embryo.
3. Cell differentiation transforms the embryo’s unspecialized stem cells into
different types of cells. about 350 different types of cells
4. Apoptosis, genetically programmed cell death, also enables prenatal
C. Early Development
By the 4 day after conception, the zygote arranges itself into a hollow sphere
of cells with a bulge of cells, the inner cell mass, on one side.
The inner cell mass eventually forms into the embryo.
The outer mass forms the support system of the embryo
Identical twins originate from the splitting in half of the inner cell mass,
resulting in the development of genetically identical individuals.
7 Fraternal twins result when two eggs are released into the fallopian tube at
the same time and are fertilized by different sperm. just being carried on at the
same time, but different sperm ast different egg
Implantation: by the end of 1 week following fertilization the process in
which the zygote embeds itself in the uterine lining and becomes dependent on the
mother for substance
After implantation, the inner cell mass becomes the embryo and the rest of
cells develop into its support system. 3 different layers forms
Top layer: nervous system, the nails, teeth, inner ear, lens of the eyes
and the outer surface of the skin
Middle layer: muscles, bones, the circulatory system, the inner layer
of the skin, and outer internal organs
Bottom layer: digestive system, lungs, urinary tracts and glands
The neural tube is a U-shaped groove formed from the top layer of
differentiated cells in the embryo.
It eventually becomes the brain and the spinal cord.
Spina bifida is a congenital disorder in which the skin over the spinal cord if not
fully closed, can originate at this point.
The support system includes
- amniotic sac: a membrane filled with a clear, watery fluid on which the fetus floats
operates as a protective buffer for the developing fetus : providing a even
temperature and cushioning against jolting.
- Placenta: permits the exchange of materials between the bloodstream of the fetus
and that of the mother semipermeable vital elements go from the mother’s body
to the fetal blood system. Waste products from the fetus cross to mother.
- Umbilical cord: the tube that contains the blood vessels that travel from the
placenta to the developing organism and back again
Protecting the Fetus
The placental membrane is a barrier against some, but not