1. Research Methods in Psychology Experimental Research –The only research method that can be used to determine cause and effect –Often called the experimental method –A researcher systematically manipulates a variable under controlled conditions.

2. Components of an Experiment Participants 1 or subjects Variable 2 – Factors that can have different values Operational Definition 3 – Describes the specific procedure used to determine the presence of a variable Independent variable (IV) 4 –Cause (what you are studying) –This is the variable that is manipulated by the experimenter Dependent variable (DV) 5 –Effect (result of experiment) –This is the variable that is measured by the experimenter –It DEPENDS on the independent variable

3. Hint A good way to determine the IV from the DV is to word the Hypothesis in the form of an “If... then...” statement. What follows the IF is the IV What follows the THEN is the DV

4. Components of an Experiment cont’d Things to worry about –Confounding Variables 6 – differences (other thehn the IV of course) between the control and experimental groups –Experimenter Bias 7 - Expectations by the experimenter that might influence the results of an experiment or its interpretation.

5. Experimental group 8 –Receives treatment Control group 9 –Does not receive treatment, but is the same in every other way –Demand Characteristics 10 – clues participants perceive about the study suggesting how they should respond. Evaluating Therapies

6. In evaluating drug therapies it important to keep the patients and experimenter’s assistants blind to which patients got real treatment and which placebo. Evaluating Therapies Double-blind Procedure 11b Participants don’t know which treatment group – experimental or control – they are in Single-blind Procedure 11a Placebo / Placebo effect 12 Fake treatment / Some paricipants expect improvement in health so they imagine it

7. Assigning participants to experimental (Breast-fed) and control (formula-fed) conditions by random assignment minimizes pre-existing differences between the two groups. Evaluating Therapies Random Assignment 13

8. Example Possible Hypothesis, “A person’s personality type is associated with their particular zodiac sign.” Select the personality profile that best describes you. –Be sure to read each one carefully and make a judgment based on the entire description. –http://www.astrology.com.au/astrology/12- signs-of-the-zodiac/http://www.astrology.com.au/astrology/12- signs-of-the-zodiac/

9. Did you choose correctly? E: Aries (March 21-April 19 th ) B: Taurus (April 20-May 20) C: Gemini (May 21-June 21) A: Cancer (June 22-July 22) F: Leo (July 23-August 22) D: Virgo (August 23-September 22) K: Libra (September 23-October 22) H: Scorpio (October 23-November 21) I: Sagittarius (November 22-December 21) L: Capricorn (December 22-January 19) J: Aquarius (January 20-February 18) G: Pisces (February 19-March 20)

10. Application Birth date/ zodiac sign = independent variable –The experimental factor that is manipulated; the variable whose effect is being studied Choice of Personality Profile = dependent variable –The outcome factor; the variable that may change in response to manipulations of the independent variable. If hypothesis is correct, the number of correct matches should exceed the number of incorrect matches. –Ideally, no incorrect matches.

11. Breast milk makes babies smarter! A summary of steps during experimentation.

12. Experimentation Like other sciences, experimentation makes the backbone of research in psychology. Experiments isolate causes and their effects. Exploring Cause and Effect