Methods of Enquiry in Psychology
Overview
This domain covers how psychologists gather evidence: observation, experiments, correlations, surveys, interviews, case studies and psychological tests. The exam tests variables, sampling, reliability and validity, and ethical safeguards.
Core rules
- Observation may be naturalistic or controlled; it must record behaviour systematically and guard against observer bias.
- Experimental method manipulates an independent variable (IV) and measures a dependent variable (DV), using control and random assignment to infer cause.
- Correlational method measures the relationship between two variables; a coefficient ranges from −1 to +1.
- Survey, interview and case study provide self-report or in-depth data but may suffer social desirability or small samples.
- Ethics: informed consent, confidentiality, voluntary participation, no harm, and debriefing after deception.
Worked example
A researcher predicts that loud noise lowers test scores. Participants are randomly assigned to a noisy or quiet room and then take the same test. The IV is noise level; the DV is test score. The quiet group is the control. Random assignment helps balance individual differences. If the noisy group scores lower, the researcher can infer a causal effect-provided extraneous variables such as time of day are controlled.
Traps that cost marks
Correlation does not prove causation. A negative correlation is not necessarily weak; it shows an inverse direction. Do not confuse random sampling with random assignment. Naturalistic observation does not involve manipulating variables. Reliability concerns consistency; validity concerns whether a tool measures what it claims.
Exam focus
Identify IV, DV, control group and ethical issues in a short scenario.