types of experiments

• What is the primary purpose of an experiment?

  To observe the effect of the IV on the DV
• What distinguishes a lab experiment from other types of experiments?

  Maximum control and a contrived setting
• What is a field experiment?

  An experiment conducted in a natural setting with less control
• Why might a field experiment have higher ecological validity than a lab experiment?

  Because it is conducted in a natural setting
• What is a natural experiment?

  An experiment where the IV changes without the experimenter's intervention
• What is a key disadvantage of natural experiments?

  Less control of extraneous variables
• What is a quasi-experiment?

  An experiment where the IV is based on an existing difference between participants
• What is a key advantage of quasi-experiments?

  Less experimenter bias in group allocation
• What are demand characteristics?

  Participants changing behavior to help or spoil the study
• How do demand characteristics affect the validity of an experiment?

  They lower validity by making the data inaccurate
• What is investigator bias?

  When the researcher influences participants' behavior or data
• How does investigator bias affect the validity of an experiment?

  It lowers validity by making the data inaccurate
• What is ecological validity?

  How reflective of real life the study setting is
• Why is ecological validity important in experiments?

  It determines if findings can be generalized to real life
• What are the four main types of experiments?

  Laboratory, field, natural, and quasi
• What is a key advantage of lab experiments?

  High control of extraneous variables
• What is a key disadvantage of lab experiments?

  Lacks ecological validity
• What is a key advantage of field experiments?

  High ecological validity
• What is a key disadvantage of field experiments?

  Less control of extraneous variables
• What is a key advantage of natural experiments?

  Increased ecological validity
• What is a key disadvantage of natural experiments?

  Less control of extraneous variables
• What is a key advantage of quasi-experiments?

  Less experimenter bias in group allocation
• What is a key disadvantage of quasi-experiments?

  More chance of extraneous variables
• What are extraneous variables?

  Variables other than the IV that could affect the DV
• How do extraneous variables affect the validity of an experiment?

  They can confound the results, lowering validity
• What are participant variables?

  Differences between participants that could affect the DV
• How do participant variables affect the validity of an experiment?

  They can confound the results, lowering validity
• What are situational variables?

  Aspects of the environment that could affect the DV
• How do situational variables affect the validity of an experiment?

  They can confound the results, lowering validity
• What is internal validity?

  Whether the experiment tests what it is supposed to
• How does internal validity affect the quality of an experiment?

  High internal validity means the experiment is accurate
• What is external validity?

  Whether the findings can be generalized to other settings
• How does external validity affect the quality of an experiment?

  High external validity means findings are generalizable
• If a researcher wants to study the effect of noise on memory in a controlled environment, which type of experiment should they use?

  Lab experiment
• If a researcher wants to study the effect of socioeconomic status on health without manipulating the IV, which type of experiment should they use?

  Natural experiment
• If a researcher wants to study the effect of gender on superstition without manipulating the IV, which type of experiment should they use?

  Quasi-experiment
• How does the control of extraneous variables differ between lab and field experiments?

  Lab experiments have high control, field experiments have less control
• How does the ecological validity of lab experiments compare to field experiments?

  Lab experiments have lower ecological validity than field experiments
• How does the ability to establish cause-and-effect relationships differ between natural and lab experiments?

  Lab experiments can establish cause-and-effect, natural experiments cannot
• How does the likelihood of demand characteristics differ between lab and field experiments?

  Lab experiments are more likely to have demand characteristics