Experimental Research Methods

Lab Experiments

• - Carried out in a controlled environment
• - High level of control over variables
• - Artificial setting
• - Independent variable is controlled in order to measure any effects on the dependent variable
• Strengths
• - Easy to replicate
• - High levels of control = accuracy = validity
• - Cause and effect can be established
• - Consent is given
• Weaknesses
• - Lacks ecological validity
• - Demand charcteristics

Field Experiments

• - Carried out in participants' natural environment
• - Experimenter still has control over the independent variable
• Strengths
• - Fewer demand characteristics
• - High ecological validity
• Weaknesses
• - Ethical issues (participants aren't always aware they're in an experiment)
• - Less control over extraneous variables
• - Harder to replicate
• - Less practical due to cost

Natural Experiments

• - Independent variable is a naturally occurring event that the researcher has no control over
• Strengths
• - High ecological validity (completely natural)
• - Fewer demand characteristics
• - Give us access to forbidden experiments
• Weaknesses
• - Ethical issues with consent
• - Not practical (expensive and time consuming)
• - Can't be replicated
• - No control over variables

Quasi-Experiments

• - Independent variable isn't manipulated by researcher (pre-existing condition)
• - Participants can't be randomly allocated to groups or conditions
• Strengths
• - High ecological validity
• - Fewer demand characteristics
• - Easy to set up (lacks random assignment)
• - Access to forbidden experiments
• Weaknesses
• - Biased results (lack of random assignment)
• - Difficult to replicate
• - Less control over independent variable
• - Ethical issues