Basic methods cont. Psych 231: Research Methods in Psychology

General research approaches Descriptive: Observational Survey Case studies Correlational Experimental

General research approaches Descriptive: Observational Survey Case studies Correlational Experimental

Causal claims We’d like to say: (variable X) causes (variable Y) To be able to do this: 1. The causal variable must come first 2. There must be co-variation between the two variables 3. Need to eliminate plausible alternative explanations

Causal claims Directionality Problem: Happy people sleep well Or is it that sleeping well when you’re happy? Airplanes and coffee spills Third variable problem: Do Storks bring babies? One might argue that turbulents cause coffee spills One might argue that spilling coffee causes turbulents

The experimental method Manipulating and controlling variables in experiments Must have a comparison At least two groups (often more) that get compared One group often serves as a control for the other group Variables Independent variable - the variable that is manipulated Dependent variable - the variable that is measured Control variables - held constant for all participants in the experiment

The experimental method Advantages Precise control possible Precise measurement possible Theory testing possible Can make causal claims 1. We know that the causal variable must have come first 2. Measure to determine if there is co-variation between the two variables 3. Good experimental manipulations are used to eliminate plausible alternative explanations

The experimental method Disadvantages Artificial situations may restrict generalization to “real world” Complex behaviors may be difficult to measure

Next time Exam 1 Covers chapters 1, 2, 3, 4, 6, 7 Scientific method Getting ideas Developing (good) theories Reviewing the literature Psychological Science Ethics Basic methodologies Multiple choice and short answer questions