3 Correlational Designs
Textbook Chapters (or similar texts)
Demonstrations
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Inquiry-based Activity: Coffee and memory
Introduction: Many of the headlines in the popular press about psychology make causal claims about correlational work, and vice versa. These can lead to misunderstandings and misinterpretations regarding what psychological science does. In this activity, students will work through a research question and decide whether it is a correlational or causational question (with the caveat that the real answer is “it depends”). By the end, students should have a better understanding of what it means for a study to be correlational or causational, in addition to being better prepared to identify types of studies that they hear about in the news and learning about third variable problems. Note that this activity will work best if the class has already covered both correlational and experimental designs.
Question to pose to students: Imagine you are a researcher investigating the question of whether/how coffee intake changes memory. Is this a correlational or a causal question?
Students form a hypothesis: In groups, have students develop a research design to answer the research question above. They should include the sample, groups being studied, and the dependent variable(s). Some groups may include more information, especially those who believe it to be a question of causality. Then, based on the research designs they have laid out, students should answer the correlation/causation question from above.
Students test their hypotheses: Have groups exchange research designs. They should again answer the correlation/causation question based on the new design that they are looking at. Then, have exchanging groups get together and discuss their answers. Did they match up? Why did they select the methodology that they did? If the groups selected different answers, can they come to an agreement as to which seems more correct?
Do the students’ hypotheses hold up?: As a class, poll the group to determine how the class voted. Use this to spark a discussion about how research can sometimes be inexact and subject to the discretion of individual scientists. Ask them, regardless of study design, what other variables might affect the study results (i.e., the third variable problem)? For example, education level of coffee drinkers vs. non-drinkers, baseline memory levels, time of day of the testing. Is it more likely that these play a role in correlational or causational studies? Depending on what had been covered in your class to this point, other topics to be discussed can include: random assignment, internal and external validity, confounds and extraneous variables, etc.
