Introduction: Ch 2

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