Methods of Developmental Psychology
I.
Introduction
A. The scientific method
B. Why study research methods
II.
Dimensions of research method
A. The normative-explanatory dimension
B. The naturalistic-manipulative dimension
1. Naturalistic observations
2. Controlled/experimental observations
C. The atheoretical-theoretical dimension
D. The ahistorical-historical dimension
III. Designs of developmental research
A. Longitudinal designs
B. Cross-sectional designs
C. Sequential designs
D. Comparative designs
E. Cross-cultural designs
IV. General methodological problems
A. Contamination
B. Researcher effects
C. Reconstruction through retrospection
D. Faulty logic
E. Inadequate definition of concepts
F. Sampling
G. Overgeneralization
Why study research methods?
Two general reasons
• Importance of being a wise and critical
consumer of research
• Bridging research and practice
Dimensions of
Developmental Research
The normative-explanatory dimension
• Normative research describes some typical
behavior
• Explanatory research provides explanations for
developmental differences
The naturalistic-manipulative dimensions
• Naturalistic research observes behavior in its
natural setting
• Controlled or experimental observations put the
child in situations that will maximize the
occurrence of the behavior of interest
The atheoretical-theoretical dimensions
• Involves the relative emphasis on theory as a basis
of research
The ahistorical-historical dimensions
• Ahistorical research studies behavior at one
particular point in time
• Historical research is concerned with the origins
and future courses of behavior
The Longitudinal Design
Age at time of testing
6 years  8 years  10 years
Involves assessing the same group of people over an extended
period of time
Advantages of the approach
• Similarities or differences in behavior across
development are seen directly
• Track performance of individuals over time, identify
common patterns and individual differences
• Can examine relations between early and late
behaviors
Drawbacks of the approach
• Biased sampling
• Repeated testing
• Cohort effects
The Cross-Sectional Design
Age group for testing
6 year-olds, 8 year-olds, & 10 year-olds
Involves assessing differently aged groups of people at the
same time of testing
Advantages of the approach
• Less time-consuming, and less expensive than
longitudinal designs
• Not as concerned with practice effects and selective
drop-out
Drawbacks of the approach
• No evidence for change at individual level; change
is between groups of people
• Cohort effects
The Sequential Design
Cohort age
(in 1995)
6-year-olds
8-year-olds
10-year-olds
Information
gained
Information
gained
CS1
CS2


Immediate L1

Enduring impact 
impact on  on children who 
6-year-olds

are now 8 yrs old 




Immediate L2

Enduring impact 
impact on  on children who 
8-year-olds

are now 10 yrs old 




Immediate L3 
Enduring impact 
impact on  on children who 
10-year-olds

are now 12 yrs old 






1st cross-sectional
2nd cross-sectional
comparison tells us
comparison tells us
at which age training
(1) which cohort
program has largest
benefited most in
immediate impact
the long run; (2)
helps to decide
which future
program might
be implemented to
maximize longterm impact
The Comparative and CrossCultural Research Designs
Comparative research
• Attempt to learn something about human
development through comparison to non-human
development
• Permits controlled tests of hypotheses that would be
unethical to test with humans
Cross-cultural research
• Compares subjects from different cultural
backgrounds
• Allows investigator to determine whether
conclusions drawn about children in one social or
cultural context generalize to children in other
contexts
• Cross-cultural differences versus cross-cultural
similarities
General Problems with Research
and Developmental Research
Contamination
• Data is influenced by factors other than those being
studied
Researcher effects
• The researcher unintentionally influences the results
of the study
• Demand characteristics
Reconstruction through retrospection
• Biases introduced through inaccurate memories
Faulty logic
• Problematic reasoning in interpreting data
Inadequate definition of concepts
• Problems in how abstract concepts are defined and
operationalized
Sampling
• Errors introduced through the type of subject
recruited for the study
Overgeneralization
• The application of findings to situations that are not
appropriate or similar enough