Research Methods in
Developmental Psychology
Michael Hoerger
Observation
 Hypothesis generation
 Laboratory Observation: Parent-child
interactions, marriages, intrusive interviews,
attachment style
 Naturalistic observation: bullying, ADHD
Case Study
 Used to gain detailed information on a single
or small number of cases, commonly used in
medicine and clinical psychology: rare
events, new events, complex events
Correlation
Correlation
 r = Strength of relationship between two
variables (-1 to +1)
 What is a “big” correlation?




Reliability: r = .90
IQ tests: r = .50 to .90
Personality research: r = .30
Life/death: r = .01
 Problem: Correlation ≠ Causation due to 3rd
variable problem and directionality problem
 Solution: Methods and argument
Cross Lagged Panel Design
(or “Cross lag panel” or “Cross panel lag”)
 Look at correlation between two variables
over time
 Does X correlated with changes in Y?

Smoking at Time 1 causes increased mile time
at Time 2
Age 20
Smoking
Cigarettes
r = -.05
r = .10
Time to
run a mile
Age 40
Smoking
Cigarettes
r = .10
r = .30
Time to
run a mile
 Look at correlation between two variables
over time
 Does X correlated with changes in Y?

Maternal depression at Time 1 causes
increased behavior problems at Time 2
Maternal
Depression
Maternal
Depression
Maternal
Depression
Child Behavior
Problems
Child Behavior
Problems
Child Behavior
Problems
THIS DRUG HAS HELPED TO
TREAT: HAY FEVER, ASTHMA
ATTACKS, ANXIETY, PAIN,
ULCERS, ENURESIS, WARTS,
ARTHRITIS, MALIGNANT
TUMORS, DIABETES, NARCOTIC
WITHDRAWAL, INSOMNIA,
COLDS, AND INATTENTIVENESS
Experiment
“id!”
 Independent variable: the
manipulation; different conditions
or groups

Alcohol vs. placebo; CBT vs. waitlist
 Dependent variables: depends on the
independent variable; the outcome variable

Age at death; depression; liver functioning
 Problem: Participants must be similar across
IV groups
 Solution: Random assignment
Survey
 Interviews, questionnaires, tests
 Used for correlational studies or as outcome
(DV) measures in experimental studies
 Highly efficient
 Can be anonymous
 Problems: Wording, Response bias (e.g.
social desirability)
 Solutions: Design with care
Online Research
 Most surveys and some experiments can be
run on the web (e.g. priming studies)
 Benefits: most efficient, useful for screening
large samples
 Risks: Lower experimental control, random
responding, technical problems, nonrepresentative sampling, ethics
 http://funpsych.com example
Physical Measures
 Physiological: changes in functioning

Galvanic skin response (sweating), pupil
dilation, heart rate
 Physical: walking speed, eye movement,
speed of responding, height, weight
 Neurological: neurotransmitter levels, brain
structure
 Benefits: reliability of measurement
 Risks: expensive, often fail to provide new
information, low correspondence
Cross-Sectional Research
 Groups differ by age

Compare children to teens to young adults to
older adults
 Differences are presumed to be the result of
age

Older people are slower due to aging
 BUT differences may simply be due to
contextual factors, such as the era each
group was born in

OR older people are slower due to differences
in nutrition growing up
Longitudinal Research
 Follow one group over time to what changes
with age

Problem: expensive, bias due to dropout
Cross-Sequential Research

Combines cross-sectional and longitudinal
research
Michael Hoerger
To cite this lecture:
 Hoerger, M. (2007, January 10). Research
Methods in Developmental Psychology.
Presented at a PSY 220 lecture at Central
Michigan University.