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Home > An Experiment to Remember: Teaching Methodology in AP Psychology
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An Experiment to Remember: Teaching Methodology in AP Psychology
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by Jeanne A. Blakeslee
St. Paul's School for Girls
Brooklandville, Maryland
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The methodology unit -- especially with a new class of high school students -- can be a challenge to teach in a way that students find interesting and memorable. When I decided to use the hypothesis that THC -- the active ingredient in marijuana -- adversely affects memory, I found an example that has the potential to amplify a range of research methods. It became easy to cover the conclusions possible from each research method, the ethics of research, and a myriad of concepts covered in the research unit, and we were able to return to this example throughout the year to reinforce the concepts learned. This is truly a memorable lesson!
The Classic Experiment
As the standard for research, I cover the classic experiment first. I begin with ethical concerns, noting that, in testing the current hypothesis, we cannot use an experiment. I introduce the Ethical Guidelines of the APA, particularly the concerns related to the current hypothesis and assignment of experimental condition.
The next set of concepts we cover is population and random and representative samples. I begin with population (for example, all high school seniors in the United States), introduce the difference between random and representative samples, and note how important size of sample can be. I discuss generalization from sample to population and introduce basic statistics -- just as a preview to a later examination. It also works to include matching and counterbalancing in this part of the conversation.
We then cover independent and dependent variables, operational definitions, and the importance of control. With the concept of control, we thoroughly examine intervening variables and the structure of the experiment to minimize confound. With operational definitions, we explore the THC delivery system and the various methods of introducing THC into the body, some of which can subvert the control necessary in an experiment. Naturally, when we cover control we include bias -- especially volunteer and experimenter bias and the methods a researcher uses to control for bias. I also include random assignment of condition in this part of the conversation.
After we explore the classic experiment, we examine other (more appropriate) methods to demonstrate our hypothesis. As we examine these other methods, we look at the kind of generalization we can make from each method and the ethical considerations that arise from each method.
The Quasi-Experiment
We examine the time-series design and see how we give up control with a quasi-experiment. We discuss giving our participants a memory test and then introducing THC to study the effects of THC on a second memory test. We discuss the kind of confounding variables that are introduced by not randomly assigning the condition.
A Correlational Study
We then think about a correlational study, taking a group of students who already use marijuana and comparing data from memory tests with those who do not use the substance. Although we have fewer ethical concerns, we have many more problems with control. Students readily see many of the important issues, including the fact that we can no longer assign causation for a decline in scores on a memory test. A conversation about whether decline in academic success causes or is caused by marijuana use provokes some interesting and memorable conversations. While we examine the correlational study, we cover the statistics used to make conclusions. We make a scatterplot and look at the strength and direction of the correlational coefficient.
Other Methods of Research
Last, we consider naturalistic and laboratory observation and the case study. It is interesting to examine the variables that are introduced with each new method and the restrictions we have on generalizing any conclusions we make to a broader population.
Statistical Analysis
After covering the various research methods, we go back to the classic experiment to examine what kind of information is necessary to make a generalization from our sample to the population. I cover measures of central tendency and variability, demonstrating how each can be a good measure but also has particular limitations. I actually teach how to compute a standard deviation -- believing that if students can calculate the standard deviation, they understand its power. We then examine the kind of conclusions we can make when our data falls into a normal curve, just by knowing the size of the sample, the mean, and the standard deviation. We look at standard scores, percentiles, and stanines. Our last exercise covers statistical significance -- naturally, we want the data for our hypothesis to be clear -- with a small standard deviation within each condition (marijuana or not) and a large difference between the experimental group and the control group in the mean number of words remembered. The null hypothesis is more memorable when the alternate hypothesis is that THC ingestion causes memory loss.
I have found that students are genuinely interested in substance use and the effect that substances have on the brain, the mind, and behavior. Each year, someone questions the hypothesis that begins the unit; invariably, someone has a friend who maintains marijuana use helps him or her to concentrate on schoolwork and achieve academically. This hypothesis leaves a good deal of room for the teacher to begin a conversation on substance use, but in a way that is nonthreatening to the students in the class. By referring to current psychological research, a teacher can trace how a hypothesis is generated, tested, and supported. By introducing the elements of good research design and the conclusion that scientists can make from each method of research, students can begin to think about the use of substances and the consequences of use.
Largely because the focus of the conversation is on research design, not substance use, an examination of the consequences of marijuana use is not particularly difficult. Students seem to remember all of these research designs -- with their limitations and ethical concerns. Comparing the classic experiment with other methods of research becomes an easy task when our hypothesis is that THC affects memory. Interestingly, students remember this one!
Jeanne Blakeslee is the dean of students and director of student services at St. Paul's School for Girls in Brooklandville, Maryland. She has taught psychology for 26 years and AP Psychology since 1992. Jeanne has served as an AP Exam Reader since 2000. She has been a member of Teachers of Psychology in Secondary Schools (TOPSS) since its inception in 1992 and received an Excellence in Teaching Award from TOPSS in 2002.
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