2.2 - approaches to research

By the end of this section, you should be able to:

Describe the different research methods used by psychologists
Discuss the strengths and weaknesses of case studies, naturalistic observation, surveys, and archival research
Compare longitudinal and cross-sectional approaches to research
Compare and contrast correlation and causation

Psychologists use a variety of methods to study behavior:

Case Studies/Clinical Studies:
In-depth, detailed examination of an individual or small group (often with unique characteristics).
Naturalistic Observation:
Observing subjects in their natural environment, without interference.
Surveys:
Collecting self-reported data through questionnaires or interviews from large groups.
Archival Research:
Analyzing existing data or records instead of collecting new data.
Longitudinal & Cross-sectional Studies:
Approaches to measure change or differences over time and across groups.

Strengths:
- Provides rich, deep, and detailed information.
- Useful for rare, unusual, or unique cases.
- Source of new insights and hypotheses for future research.
Weaknesses:
- Limited generalizability—findings may not apply to broader population.
- Can be subjective (researcher bias).
- Cannot determine cause and effect.

Strengths:
- High ecological validity; authentic, real-world behaviors.
- Sometimes only feasible method for certain behaviors.
Weaknesses:
- Lack of control over variables (can’t manipulate or predict occurrences).
- May involve observer bias.
- Cannot always determine the reasons for observed behaviors.
- Time-consuming and sometimes expensive.

Strengths:
- Can gather data from large, diverse samples efficiently.
- Cost-effective.
- Results are often generalizable if sampled properly.
Weaknesses:
- Limited depth of information per participant.
- Relies on honest and accurate responses (often affected by social desirability bias or memory errors).
- Wording and structure of questions may influence answers.

Strengths:
- Cost-effective and time-efficient (data already collected).
- Useful for historical or large-scale patterns.
Weaknesses:
- No control over how or what data was collected.
- Incomplete or inconsistent data sets may reduce quality of findings.
- Only as good as the records available; may not answer specific new questions.

Approach	Description	Strengths	Weaknesses
Longitudinal	Same group studied repeatedly over time	Tracks real changes within people; less affected by generational effects	Time-intensive, costly, high participant attrition
Cross-sectional	Different groups (e.g., age cohorts) compared at one time	Quicker and cheaper; no attrition problem	Cannot track individual development; generational (cohort) differences

Use Case Example:

Longitudinal: Tracking smoking habits and cancer rates in the same people across decades.
Cross-sectional: Comparing 20-, 30-, and 40-year-olds’ attitudes about health at a single point in time.

Correlation:
Implies a relationship between two variables (as one changes, so does the other), but does not prove that one variable causes the other.
- Example: As ice cream sales rise, drowning incidents also rise. Both are related to hot weather, not to each other.
Causation:
Demonstrates that change in one variable directly causes change in another; can only be inferred through experimental research with controlled manipulation of variables.
- Example: Coming to class (IV) causes better exam scores (DV), only if other variables are controlled and a true experiment is conducted.

Important:
Case studies, surveys, naturalistic observation, and archival research can identify correlations but NOT causation.

Method	Data Source	Generalizability	Depth/Detail	Control of Variables	Shows Causation?
Case Study	Few/single cases	Low	High	Low	No
Naturalistic Observation	Natural behaviors	Moderate	Moderate	Low	No
Survey	Large groups/self-report	High	Low	Low	No
Archival Research	Existing records	Varies	Varies	None	No
Experiment (not covered here)	Manipulated variables	High	Varies	High	Yes (if designed properly)

Different psychological research methods each have unique uses, advantages, and limitations.
Only experiments can establish causation; other methods are primarily used to find correlations.
Survey and archival research are efficient for large-scale studies; case studies and naturalistic observation offer depth and ecological validity but limited generalizability.
Longitudinal research tracks changes in the same subjects over time; cross-sectional studies compare different groups at one point in time.