Types of Experiments

Lab Experiments:Lab experiments take place in controlled environments within which the researcher manipulates the IV and records the effect on the DV whilst maintaining strict control of extraneous variables. Strengths: High control over extraneous variables High internal validity because we know the effect on the dependent variable is the result of manipulation of the independent variable Easy to replicate Weaknesses: Lacks generalisability Artificial environment Low external validity as people may act differently in unusual environments Participants are aware they are being tested so may show demand characteristics Low mundane realism - not performing everyday tasks

Field Experiments:Field experiments take place in natural environments within which the researcher manipulates the IV and records the effect on the DV.Strengths: High mundane realism because the environment is more natural Produces more valid authentic behaviour High external validity because the participants are unaware they are being studied Weaknesses: Loss of control of extraneous variables Replication is very difficult Ethical issues - participants are unaware they are being studied so cannot consent to being studied which may lead to invasion of privacy

Natural Experiments:Natural experiments are experiments where the change on the IV happens naturally and would have occurred whether the researcher had been there or not. The researcher records the effect on the DV.Strengths: Provide opportunities for research that may not otherwise be undertaken for practical or ethical reasons High external validity because it involves the study of real life issues/problems as they happen Weaknesses: A naturally occurring event may be rare reducing the opportunities for research Participants may not be randomly allocated to experimental conditions meaning the researcher may be less sure whether the IV affected the DV

Quasi Experiments:Quasi experiments are experiments where the IV has not been determined/manipulated it just exists e.g. age/genderStrengths:Often carried out in controlled conditions so have high control over extraneous variablesWeaknesses:Participants are not randomly allocated to conditions so there may be confounding variables