GOALS OF
DEVELOPMENTAL
PSYCHOLOGY

Describe, explain, and optimize
human development
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GOALS OF DEVELOPMENTAL
PSYCHOLOGY

1. DESCRIBE
– characterize the behavior of human
beings of different ages and trace
how it changes with age
– normal development & individual
differences
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GOALS OF DEVELOPMENTAL
PSYCHOLOGY

2. EXPLAIN
– understanding why humans develop as
they do
– why people develop similarly &
differently.
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GOALS OF DEVELOPMENTAL
PSYCHOLOGY

3. OPTIMIZE
– how people can be helped to develop
in a positive direction
– prevention & remediation
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METHODS OVERVIEW




Psy 311: Methods
WHO:
WHAT:
HOW:
WHEN:
Sampling
Measures
METHODS
DESIGN
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CHALLENGE TO
LIFE-SPAN DEVELOPMENT

METHODS
– How can we demonstrate causality?
– How can we study different pathways of
development?
– How can we study changing people in a
changing world?
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METHODS

TYPES OF METHODS
– Correlational
– Experimental
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CORRELATIONAL METHOD

WHAT IS IT?
– Looks at naturally existing relationships.
– Studies people who have already had
experiences.
– Assigned “naturally” to groups.
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CORRELATIONAL METHOD
(cont.)

DISADVANTAGES
– Can’t prove cause-effect relations
between variables.
• Could be the reverse effect.
• Could be something else that causes
both variables.
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C
Child’s
Gender
A
Teacher
Involvement
B
Child’s
Motivation
EXPERIMENTAL METHOD

WHAT IS IT?
– 1. Random assignment of people to
“treatment” and “control” groups.
– 2. Manipulate the independent or
“causal” variable.
– 3. Comparison groups are identical on
everything but the treatment.
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EXPERIMENTAL METHOD
(cont.)

ADVANTAGES
– Can establish cause-effect relations
between variables.
• Does show cause and effect.
– Does not rule out reverse relationship.
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EXPERIMENTAL METHOD
(cont.)

DISADVANTAGES
– “Treatment” may be artificial.
– May not work this way in the real world.
– “Can” cause vs. “does” cause.
– Lots of interesting causal variables
cannot be manipulated.
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CORRELATIONAL METHOD
(cont.)

ADVANTAGES
– Can be applied to data collected in
natural settings.
– Can be more applicable to the real
world.
– Can be used to study issues that cannot
be studied experimentally.
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EXPANDING METHODS
(cont.)

CORRELATIONAL
– Examining beginnings.
– Adding time sequences.

EXPERIMENTAL
– Natural experiments.
– Optimizing interventions.
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DEVELOPMENTAL
DESIGNS

TYPES OF DESIGNS
– Cross-Sectional
– Longitudinal
– Sequential
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CROSS-SECTIONAL
DESIGN

WHAT IS IT?
– At one time point.
– Look at people of different ages.
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CROSS-SECTIONAL
DESIGN (cont.)

WHAT DO YOU GET?
– Information about age differences.
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CROSS-SECTIONAL
DESIGN (cont.)

DISADVANTAGES
– 1. Age differences may be COHORT
differences.
• BIRTH COHORTS: People of the same
generation or born at about the same time.
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CROSS-SECTIONAL
DESIGN (CONT)

DISADVANTAGES
– 2. Provides no information about...
– how a person changes over time.
– how earlier experiences influence later
development.
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LONGITUDINAL DESIGN

WHAT IS IT?
– At many points in time; repeatedly
– Follow the same group of people
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LONGITUDINAL DESIGN
(CONT)

WHAT DO YOU GET?
– Information about age changes
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LONGITUDINAL DESIGN
(cont.)

ADVANTAGES
– 1. Actually can study how a person changes
over time.
– 2. Actually can study how different people
change over time.
– 3. Actually can study…
• how earlier developments are linked to later
development.
• how earlier experiences influence later
development.
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LONGITUDINAL DESIGN
(cont.)

DISADVANTAGES
– 1. Age changes may be HISTORICAL
changes.
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LONGITUDINAL DESIGN
(cont.)

DISADVANTAGES
– 2. Participants may be affected by
participation in study.
• e.g., repeated testing
– 3. Participants may drop out.
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LONGITUDINAL DESIGN
(cont.)

DISADVANTAGES
– 4. Measures may later prove
inadequate.
– 5. Practical problems
• time consuming
• expensive
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CROSS-SECTIONAL
DESIGN (cont.)

ADVANTAGES
– 1. Does give information about age
differences.
– 2. Hints at developmental trends.
– 3. Practical.
• takes little time to conduct
• inexpensive.
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SEQUENTIAL DESIGN

WHAT IS IT?
– Combines cross-sectional and
longitudinal designs.
– Longitudinal studies on multiple
generations or cohorts.
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SEQUENTIAL DESIGN (cont.)

WHAT DO YOU GET?
– 1. Age differences and Cohort
differences.
– 2. Age changes and Historical changes.
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SEQUENTIAL DESIGN (Cont)

ADVANTAGES
– 1. Compares development at different
historical periods
– 2. Compares development of different
cohorts
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SEQUENTIAL DESIGN (Cont)

DISADVANTAGES
– 1. Complex
– 2. Time consuming
– 3. Still only generalizable to the
cohorts and historical periods you DID
measure
– 4. You may find effects you do not want.
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DESIGNS FOR
DEVELOPMENTAL QUESTIONS
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CROSS-SECTIONAL

Advantages
– Age differences
– Suggests change
– Inexpensive,
quick
Psy 311: Methods

Disadvantages
– Age differences
could be cohort
differences
– No information
about change or
effects of early
experience
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LONGITUDINAL

Advantages
– Age change
– How people
develop differently
– Connections
between early &
later development
Psy 311: Methods

Disadvantages
– Age change could
be historical
change
– Expensive & long
– Drop out
– Repeated testing
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SEQUENTIAL

Advantages
– Age changes
– Historical changes
in development
Psy 311: Methods

Disadvantages
– Really complex,
expensive & long
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WHAT IS THE BEST
DEVELOPMENTAL DESIGN?

Age differences
– CROSS-SECTIONAL
• exploratory

Age changes
– LONGITUDINAL
• effects of earlier experiences

Historical changes
– SEQUENTIAL
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WHAT IS THE BEST
DEVELOPMENTAL DESIGN
(CONT)?

Truly Developmental
– LONGITUDINAL

Most Complete
– SEQUENTIAL

Depends on the question
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LAST NAME, first name

1. Name the major problem with each
design:
a) Correlational
b) Experimental
c) Cross-sectional
d) Longitudinal
e) Sequential
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END
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