Types of research method
IB Psychology· Research methodology· 14 min read
1. Core concept
Research methods fall into two broad families. Experimental methods manipulate an independent variable while controlling others, so they can support cause-and-effect claims — true/laboratory, field, quasi- and natural experiments differ in how much is controlled and where. Non-experimental methods — correlational studies, case studies, naturalistic observations, interviews and surveys — describe or relate variables without manipulation, trading causal power for realism or depth. Knowing the family tells you what kind of conclusion a study can and cannot support.
2. Key studies
IB Psychology answers must be supported by named studies. Learn these to cite as evidence:
Bandura, Ross & Ross (1961)
Children who watched an aggressive model imitated its aggression toward a Bobo doll, unlike controls. — An EXPERIMENT — a manipulated model plus a control condition — so it can argue that observation caused the imitation.
Rosenquist, Fowler & Christakis (2011)
Depressive symptoms were correlated between individuals up to three degrees apart in a social network. — A CORRELATIONAL (non-experimental) study — it establishes a relationship but, without manipulation, cannot show the network causes the spread.
3. Evaluation (AO3)
Strength — the method signals the claim — Classifying a study places clear limits on its conclusions (experimental = possible cause, correlational = relationship only), which is the first step in evaluating it.
Limitation — boundaries blur — Quasi- and natural experiments lack full random allocation, and field studies mix features, so the label alone does not settle how much control a study really had.
4. Scope
5. Common Pitfalls
Wrong move:
Any study with a comparison is 'an experiment', and all experiments are alike.
Why:
A frequently penalised misconception in IB Psychology exams.
Correct move:
A true/laboratory experiment manipulates an IV under control; field and quasi-experiments differ and are not interchangeable with it. Identify the specific method, not just 'experiment', and give the required number of characteristics.
Going deeper
- Strengths and limits of methodseach method's characteristic strengths and limits are RM_13.
- External variables and causalitywhy non-experimental designs cannot pin causality is RM_15.