CHAPTER 8: SOLVING PROBLEMS: CONTROLLING EXTRANEOUS VARIABLE

• physical variables are aspects of the testing that needs to be controlled
• elemination removes extraneous physical variables
• constancy of conditions controls extraneous physical variables by keeping all aspects of the treatment conditions identical
• balancing controls extraneous variables by equally distributing their effects across treatment conditions
• social variables - aspects the relationship between subjects and experimenters that can influence experimental results
• social variables:

  1. demand characteristics
  2. experimenter bias
• single-blind experiment - subjects are not told their treatment condition
• placebo effect - subject receives an inert treatment and improves because of positive expectancies
• cover story - false plausible explanation of the experimental procedures
• experimental bias - any behavior by the experimenter that can confound the experiment.
• rosenthal effect - phenomenon in which experimenters treat subjects differently based on their expectations
• rosenthal effect is also called the pgymalion effect and self-fulfilling prophecy
• single-blind characteristics - only control demand characteristics

  double-blind characteristics - control both demand characteristics and experimenter bias
• personality variables - personal characteristics that subjects brings to the experimental setting.
• context variables - extraneous variables created by the research setting environment