Chapter 2 Psychologyʼ’s Scientific Method
Descriptive Research Descriptive research is about determining it’s basic dimensions & defining what this thing is and how often it occurs
Descriptive Research Goal: Describing a phenomenon
• observation • surveys and interviews • case studies
Case Study: Phineas Gage
Psychologist vs Psychiatrist • Gist vs Trist
• Trist = Can Prescribe Drugs, Med School
• Gist = no drugs
Correlation and Causation • correlation does not equal causation
• third variable problem
• longitudinal design
Experimental Research Goal: Determine causation
• random assignment
• independent variable (IV) – manipulation
• dependent variable (DV) – measurement
IV’s and DV’s : How to Distinguish Use “if….then” statement Example: If subjects drink seven beers then their vision will be blurred.
IV
DV
Blurred vision is dependent on drinking seven beers.
Experimental Research Experimental Group • independent variable is manipulated (IV)
Control Group • Comparison group
The Experiment • Hypothesis:
• Manipulation of the IV: • Exp. Group – 250 students = Drank 7 beers
Drinking beer blurs vision • Independent variable (IV): drinking beer • Dependent variable (DV): eyesight/vision • Random Subjects: 500 college students
• Control group – 250 students = Drank 7 waters
• Measure DV: Experimental group had more blurred vision • Conclusion: Drinking 7 beers blurs vision
Research Cautions • experimenter bias
• research participant bias
• placebo effect
• double-‐blind experiment
Research Participants Population • entire group about whom conclusion drawn
Sample • portion of population actually observed
Random Sample • equal chance of being selected • Subset of the population
Research Settings “Artificial” world – laboratory setting • controlled setting
Real world -‐ natural setting • naturalistic observation
What are the advantages and disadvantages
of each setting?
Stanley Milgram & his ‘Shock Generator’
The Milgram Experiment Classified Ad