Research methods

• Repeated measures:

  • Participants take part in every condition
  • No participant variables
  • Fewer participants needed
  • Risk of demand characteristics (guessing the aim of the experiment)
  • Risk of order effects such as fatigue/boredom
• Independent measures:

  • Each participant is only used in one condition
  • Quick
  • No order effects
  • High risk of participant variables
  • More participants needed
• Matched pair design:

  • Participants are matched with a twin by characteristics
  • Less risk of demand characteristics as extraneous variables are kept constant between conditions
  • Participants can never be completely matched
  • Time consuming and expensive
• • Systematic sampling: Selecting participants at fixed intervals from the target population
  • Avoids researcher bias
  • Usually representative but may still have researcher bias
• Sampling methods:

  • Random sampling:
  • Every member of a population has an equal chance of being selected
  • No bias
  • Takes more time and effort than other methods
  • Stratified sampling:
  • Dividing the target population into important subcategories
  • Selecting in proportion to the population
  • Most representative out of all of the methods
  • Very lengthy, participants might not even want to take part
  • Opportunity sampling:
  • Simply selecting those who are available at the time
  • Relatively easy to do
  • Likely to be unrepresentative
• Key words:

  • Theory: An explanation of why something happens
  • Hypothesis: A specific prediction of what will happen when you control the situation
  • Study: Uses a method to test a hypothesis
  • Independent variable (IV): The part you manipulate/change to test the effects on the DV
  • Dependent variable (DV): The part you measure
  • Control variable: Results to compare your main results to
  • Extraneous variables (EV): The things that affect the DV but are not an IV
• Writing hypotheses:

  • Start with 'participants will'
  • Example: Ben thinks that people will be happier when it is sunny
  • IV: The weather (Sunny or rainy)
  • DV: The results of the mood questionnaire
  • Participants will be happier on a sunny day than on a rainy day and results will show this
• Designing research:

  • Interviews:
  • A face-to-face conversation
  • Produces extensive information
  • Only way to get information from participants who can't write/find it difficult to express themselves on paper
  • Can be difficult to analyse
  • Questionnaires:
  • Written questions
  • Can gather lots of information quickly
  • Easy to analyse
  • Participants may not answer truthfully, questions may be unclear
  • Observation:
  • Watching participants
  • Provides a better indication of behavior
  • Participants act naturally
• • Ethical issues: Observers have expectations which may influence what they see or hear
  • Volunteer sample:
  • Opportunity sample
  • Whoever's available
• Ethical considerations:

  • Informed consent:
  • Researchers tell participants exactly what is going to happen to them in the experiment
  • Giving participants all of the information
  • Deception:
  • Means telling participants lies and deceiving them about something to do with the study
  • Should be avoided
  • Confidentiality:
  • Keeping personal information confidential
  • Debrief:
  • Telling participants what the study was about before they leave
  • Withdrawal:
  • Giving participants the opportunity to leave the study at any time if they no longer want to take part
• • All participants should be told that they have the right to withdraw at any time
  • Protection:
  • Participants should not be harmed psychologically or physically
  • Can do, can't do with participants
• Ethical terminology:

  • Standardised instructions:
  • Gives an outline of the study so participants have some awareness of what is required
  • Brief:
  • Telling participants exactly what they are going to do before they take part
  • Every participant must receive the same information
  • Consent:
  • Participants should give their agreement to take part in a psychological experiment
• Methods of investigation:

  • Field experiment:
  • Conducted in the 'real world'
  • More realistic than other methods
  • Good validity
  • Standardised procedures like lab experiments help control extraneous variables
  • Less control over extraneous variables
  • May have special ethical issues
  • Natural experiment:
  • Done in a natural environment
  • Uses a circumstance that would occur without experimenter manipulation
  • High validity
  • Natural event being studied may only occur rarely, fewer opportunities for research
• • Could have unique characteristics of participants, affecting the results as they could act as an extraneous variable
  • Laboratory experiment:
  • Usually conducted in a designed room with full experimenter control
  • Extraneous variables can be controlled, stronger results
  • Standardised procedures, can be repeated by another researcher and validates results
  • Unlike everyday life, results may not generalize to everyday world
  • Low validity
  • Participants know they are being tested which could affect their behavior
• Measures of central tendency:

  • Mode:
  • The number that appears the most in a set of data
  • Useful when the data is in categories
  • Not useful when there is more than one mode
  • Median:
  • The middle value once all of the values are in order
  • Not affected by extreme scores
  • Does not take into account all of the numbers
  • Mean:
  • Adding up all of the numbers and dividing by how many there are
  • Makes use of all of the data
  • If there are extreme values, it may not be representative of all of the data
• Why might interviews be better than questionnaires?


  Pps may not be able to express themselves on paper