experiments

what are the four types of experiments?

• laboratory experiments

• field experiments

• natural experiments

• quasi experiments

what are laboratory experiments?

experiments conducted in a highly controlled environment (usually a lab) where the researcher manipulates the IV and measures the DV

what are the strengths of laboratory experiments?

• high internal validity - high control over extraneous variables means its easier to establish cause and effect

• high external reliability - high level of control allows replication to be more possible

what are the weaknesses of laboratory experiments?

• low ecological validity - environment and tasks are often artificial so its hard to generalise to the real world

• demand characteristics - high control means participants may work out what the research is about, or change their behaviours

what are field experiments?

experiments where the IV is manipulated but the experiment occurs in a natural, more everyday setting

what are the strengths of field experiments?

• higher ecological validity - more realistic and less artificial than a lab

• lower demand characteristics - due to participants being in a natural environment and unaware they’re being studied

what are the weaknesses of field experiments?

• less control of extraneous variables - harder to find cause and effect, this could decrease the validity of the results

• ethical issues - if participants are unaware they’re being studied they can’t consent

what are natural experiments?

experiments that have a naturally occurring IV

what are the strengths of natural experiments?

• less ethical issues - the IV is naturally occurring so researchers don’t need to manipulate

• high external validity - study real-world issues and problems as they occur so high applicability

what are the weaknesses of natural experiments?

• naturally occurring events happen rarely - reduces opportunities for research and limits generalisability

• low internal validity - more confounding variables as conditions are pre-existing so they may be other factors that can’t be controlled

what are quasi experiments?

experiments that involve a pre-existing IV but the researcher has a degree of control over the task or environment

what are the strengths of quasi experiments?

• high levels of control - therefore high replicability and reliability

• less ethical issues - researchers don’t manipulate IV as it is naturally occurring

what are the weaknesses of quasi experiments?

• can’t randomly allocate participants to conditions so may be confounding variables

• less control of extraneous variables - harder to find cause and effect, this could decrease the validity of the results