Research designs and variables week 3

• The scientific method

  • Experiments isolate cause and effect
  • Manipulate one variable at a time
  • Hold everything else constant
  • Can establish the effect of the manipulated variable
• Experiment


  A study that manipulates an independent variable to observe its effect on a dependent variable
• Variables


  • Independent variables (IVs)
  • Dependent variables (DVs)
• Other types of variables


  • Confounding variables
  • Extraneous variables
• Experimental designs


  • Within-participants experiment
  • Between-participants experiment
• Quasi-experimental designs


  • No random allocation to experimental conditions
  • No manipulation of an independent variable
• Group difference


  No real treatment or intervention, e.g. gender differences
• Observation


  Record freely produced behaviour in relatively natural environment
• Survey


  Interviews and questionnaire responses
• Archival data


  Public records and statistics
• Non-experimental designs


  • Lack the control of a true experiment
  • Difficult to replicate methodologies
• Replicability


  Research must be able to be repeated to obtain the same result
• Falsifiability


  Hypotheses must be able to be conclusively disproven
• Occam's razor


  When two or more equally good theories exist, the simplest should be preferred
• Parts of a psychological report


  • Title and Abstract
  • Introduction
  • Method
  • Results
  • Discussion
• Title


  First section to write
• Introduction


  Has subsections, often the 'easiest' and quickest section to write
• Method


  Design, IVs and DVs, Participants, Materials, Procedure
• Results


  Examples in APA format
• Discussion


  • History in past tense, current theories present
  • General comments
  • Use of personal pronouns
  • Use of tenses
  • Avoid contracting words
• What is a within-participant design


  Everyone takes part in all conditions and everyone experiences every level of the IV
• What is a between-participants design? 


  Different groups of individuals take part in one condition and each participant only experiences one level of the IV