Variables

• Independent variable-

  -One the experimenter manipulates

  -Assumed to have a direct effect on the DV
• Dependent variable -

  Factor or variable that the experimenter measures
• Extraneous variables -

  One which might interfere with the DV

  -Sometimes known as uncontrolled variables
• Confounding variable-

  -One which has definitely interfered with DV, and confounded the results
• Situational Extraneous Variables -

  -Stem from aspects of environment where the study is conducted

  -These are things like; noise, light, temperature, time of day, way instructions are given
• Participant extraneous variables-

  -Stem from ways in which participants may differ from each other

  -Things like: differences in IQ, reading ability, having dyslexia , being tired, gender, age
• Demand characteristics and Investigator effects are also extraneous variables
• Investigator effects-

  -The researcher can affect the behaviour of participants thus affecting the results of study
• Demand characteristics-

  -Participants may change their behaviour responding to the perceived demands of study
• Demand characteristics can occur in following situations-

  -Participants may worry about being in psychological study and want to appear normal so change their behaviour

  -They may try to guess what investigation is about then behave in a way they think the investigator wants them to

  -May deliberately try to behave in unexpected way

  -May want to look good (social desirability)