Experimental Methods

Experiments are the primary method psychologists use to establish cause-and-effect relationships. In an experiment, the researcher manipulates the IV and measures the DV while controlling extraneous variables. However, there are different types of experiment, each with its own strengths and limitations.

---

Types of Experiment

1. Laboratory Experiment

A laboratory experiment takes place in a controlled environment (usually a laboratory or specially prepared room). The researcher has high control over variables.

Example: Loftus and Palmer (1974) — participants watched a film of a car accident in a controlled setting and were asked leading questions.

Advantage	Disadvantage
High control over extraneous variables — easier to establish cause and effect	Low ecological validity — the artificial setting may not reflect real-life behaviour
Easy to replicate due to standardised procedures	Demand characteristics — participants may behave differently because they know they are being studied
Can precisely measure the DV	May lack mundane realism — tasks may not be similar to real-world activities

2. Field Experiment