Methods of Developmental PsychologyI. 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 observations2. Controlled/experimental observations

C. The atheoretical-theoretical dimension D. The ahistorical-historical dimension

III. Designs of developmental researchA. Longitudinal designsB. Cross-sectional designsC. Sequential designs D. Comparative designsE. Cross-cultural designs

IV. General methodological problemsA. ContaminationB. Researcher effectsC. Reconstruction through retrospectionD. Faulty logicE. Inadequate definition of conceptsF. SamplingG. 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 Information Information(in 1995) gained CS1 gained CS2

6-year-olds Immediate L1 Enduring

impact impact on on children who 6-year-olds are now 8 yrs

old

8-year-olds Immediate L2 Enduring

impact impact on on children who 8-year-olds are now 10 yrs

old

10-year-olds 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 mightbe

implemented to

maximize long-term impact

The Comparative and Cross-Cultural 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