Unit 2 (C): Experimental Research Designs Mr. McCormick A.P. Psychology

Do-Now (Discussion) What is a correlation? What is a correlation? What is a positive correlation? What is a positive correlation? What is the correlation coefficient (r) for a perfect positive correlation? What is the correlation coefficient (r) for a perfect positive correlation? What does a positive correlation look like? What does a positive correlation look like? Provide an example of two things that may be positively correlated. Provide an example of two things that may be positively correlated. What is a negative correlation? What is a negative correlation? What is the correlation coefficient (r) for a perfect negative correlation? What is the correlation coefficient (r) for a perfect negative correlation? What does a negative correlation look like? What does a negative correlation look like? Provide an example of two things that may be negatively correlated. Provide an example of two things that may be negatively correlated.

Non-Experimental Research Designs Activity: Activity: With a partner, create an example of a psychological phenomenon a psychologist would likely study for any 2 of the following non-experimental research designs. Explain why. With a partner, create an example of a psychological phenomenon a psychologist would likely study for any 2 of the following non-experimental research designs. Explain why. Naturalistic Observation Naturalistic Observation Case Study Case Study Survey Survey Longitudinal Study Longitudinal Study Cross-Sectional Study Cross-Sectional Study Correlation Correlation For each example, provide a short explanation of why each research design would be most preferable for that scenario For each example, provide a short explanation of why each research design would be most preferable for that scenario

Experimental Research Designs Experiment: Experiment: A research method in which an investigator manipulates one or more variables (independent variables) to observe the effect on some behavior or mental process (dependent variable) A research method in which an investigator manipulates one or more variables (independent variables) to observe the effect on some behavior or mental process (dependent variable)

Experimental Research Designs Why might psychological researchers prefer experimental research designs over descriptive or correlational research designs? Why might psychological researchers prefer experimental research designs over descriptive or correlational research designs? What type of research might require an experimental design? What type of research might require an experimental design?

Experimental Research Designs Experiments begin with a hypothesis Experiments begin with a hypothesis (e.g. “Caffeine improves test performance”) (e.g. “Caffeine improves test performance”)

Experimental Research Designs Experimenters must employ variables: Experimenters must employ variables: Independent Variable: Independent Variable: Manipulated/changed by experimenter to observe its effects (e.g. Coffee/Redbull) Manipulated/changed by experimenter to observe its effects (e.g. Coffee/Redbull) Dependent Variable: Dependent Variable: The effects/changes that occur in relation to the independent variable (e.g. improved test performance) The effects/changes that occur in relation to the independent variable (e.g. improved test performance) Confounding Variables: Confounding Variables: Factors other than the independent variable that might produce an effect in an experiment (e.g. one’s natural intelligence) Factors other than the independent variable that might produce an effect in an experiment (e.g. one’s natural intelligence)

Experimental Research Designs Experimenters divide participants into two groups (often randomly): Experimenters divide participants into two groups (often randomly): Experimental Group: Experimental Group: Independent variable is applied (e.g. Coffee is given to participants) Independent variable is applied (e.g. Coffee is given to participants) Control Group: Control Group: Treated the same way as experimental group, but independent variable is not applied (e.g. No coffee is given to participants) Treated the same way as experimental group, but independent variable is not applied (e.g. No coffee is given to participants)

Experimental Research Designs Why would experimenters wish to employ an experimental and a control group?

Experimental Research Designs Does breast-feeding a child improve their intelligence later in life?

Review A psychologist wishes to test the effects of cell phone use on driving. To do so, he creates an experiment in which 80 participants partake in a driving test. 40 participants must talk on their phone while driving, while 40 participants may not. Identify the following: A psychologist wishes to test the effects of cell phone use on driving. To do so, he creates an experiment in which 80 participants partake in a driving test. 40 participants must talk on their phone while driving, while 40 participants may not. Identify the following: Hypothesis Hypothesis Independent Variable Independent Variable Dependent Variable Dependent Variable Confounding Variables Confounding Variables Experimental Group Experimental Group Control Group Control Group

Homework Unit 2 Quiz: “Research Methods” Unit 2 Quiz: “Research Methods”