Chapter 8

• Balancing


  A technique used to control the impact of extraneous variables by distributing their effects equally across treatment conditions.
• Constancy of condition


  A control procedure used to avoid confounding; keeping all aspects of the treatment conditions identical except for the independent variable that is being manipulated.
• Context variable


  Extraneous variable stemming from procedures created by the environment, or context, of the research setting.
• Cover story


  A plausible but false explanation of the procedures in an experiment told to disguise the actual research hypothesis so that subjects will not guess what it is.
• Demand characteristics

  • The aspects of the experimental situation itself that demand or elicit particular behaviors.
  • Can lead to distorted data by compelling subjects to produce responses that conform to what subjects believe is expected of them in the experiment.
• Double-blind experiment

  • An experiment in which neither the experimenter nor the subjects know which treatment condition the subjects are in.
  • Used to control experimenter bias.
• Elimination


  A technique to control extraneous variables by removing them from an experiment.
• Experimenter bias


  Any behavior of the experimenter that can create confounding in an experiment.
• Personality variables


  The personal characteristics that an experimenter or volunteer subject brings to the experimental setting.
• Physical variables


  Aspects of the testing conditions that need to be controlled.
• Placebo effect

  • The result of giving subjects a pill, injection, or other treatment that actually contains none of the independent variable.
  • The treatment elicits a change in subjects’ behavior simply because subjects expect an effect to occur.
• Rosenthal effect

  • The phenomenon of experimenters treating subjects differently depending on what they expect from the subjects.
  • Also called the Pygmalion effect.
• Single-blind experiment

  • An experiment in which subjects are not told which of the treatment conditions they are in.
  • A procedure used to control demand characteristics.
• Social variables


  The qualities of the relationships between subjects and experimenters that can influence the results of an experiment.