đ > Show > đ4 min readâ˘december 9, 2021 AP Psychology đ§There are various types of research methods in psychology with different purposes, strengths, and weaknesses.
Whenever researchers want to prove or find causation, they would run an experiment. An experiment you'll learn about in unit 9 that was run by Solomon Asch investigated the extent to which one would conform to a group's ideas. Image Courtesy of Wikipedia. Each person in the room would have to look at these lines above and state which one they thought was of similar length to the original line. The answer was of course obvious, but Asch wanted to see if the "real participant" would conform to the views of the rest of the group. Asch gathered together what we could call "fake participants" and told them not to say line C. The "real participant" would then hear wrong answers, but they didn't want to be the odd one out, so they conformed with the rest of the group and represented the majority view. In this experiment, the "real participant" was the control group and about 75% of them, over 12 trials, conformed at least once. There could be a correlational study between anything. Say you wanted to see if there was an association between the number of hours a teenager sleeps and their grades in high school. If there was a correlation, we couldn't say the more hours slept đ¤, the higher the grades are, but we could say that they go hand in hand đ¤ together. Surveys are used all the time, especially in advertising and marketing. They are often distributed to a large number of people and results are returned back to researchers. If a student wanted to observe how many people fully stop at a stop sign, they could watch the cars from a distance and record their data. This is a naturalistic observation, since the student is in no way influencing the results. Other than the example in the table, here is another one: A man named Phineas Gage was working near the railroad when an iron rod penetrated his cheek through his skull and brain. Image Courtesy of Vermont Journal This is a case study, since he is an individual with a unique circumstance. Gage actually survived this but his whole personality changed since part of his brain was altered. They did a case study to learn more about the impact of this incident. Was this guide helpful?
The information presented so far in this chapter is enough to design a basic experiment. When it comes time to conduct that experiment, however, several additional practical issues arise. In this section, we consider some of these issues and how to deal with them. Much of this information applies to nonexperimental studies as well as experimental ones. Recruiting ParticipantsOf course,at the start of any research projectyou should be thinking about how you will obtain your participants. Unless you have access to people with schizophrenia or incarcerated juvenile offenders, for example, then there is no point designing a study that focuses on these populations. But even if you plan to use a convenience sample, you will have to recruit participants for your study. There are several approaches to recruiting participants. One is to use participants from a formal âan established group of people who have agreed to be contacted about participating in research studies. For example, at many colleges and universities, there is a subject pool consisting of students enrolled in introductory psychology courses who must participate in a certain number of studies to meet a course requirement. Researchers post descriptions of their studies and students sign up to participate, usually via an online system. Participants who are not in subject pools can also be recruited by posting or publishing advertisements or making personal appeals to groups that represent the population of interest. For example, a researcher interested in studying older adults could arrange to speak at a meeting of the residents at a retirement community to explain the study and ask for volunteers. âStudy.âThe poster reads: Volunteers needed for a scientific study investigating whether people can distinguish between scientific studies and kidney-harvesting scams. (Healthy Type-O Adults Only).
Even if the participants in a study receive compensation in the form of course credit, a small amount of money, or a chance at being treated for a psychological problem, they are still essentially volunteers. This is worth considering because people who volunteer to participate in psychological research have been shown to differ in predictable ways from those who do not volunteer. Specifically, there is good evidence that on average, volunteers have the following characteristics compared with nonvolunteers (Rosenthal & Rosnow, 1976):
This difference can be an issue of external validity if there is reason to believe that participants with these characteristics are likely to behave differently than the general population. For example, in testing different methods of persuading people, a rational argument might work better on volunteers than it does on the general population because of their generally higher educational level and IQ. In many field experiments, the task is not recruiting participants but selecting them. For example, researchers Nicolas GuĂŠguen and Marie-Agnès de Gail conducted a field experiment on the effect of being smiled at on helping, in which the participants were shoppers at a supermarket. A confederate walking down a stairway gazed directly at a shopper walking up the stairway and either smiled or did not smile. Shortly afterward, the shopper encountered another confederate, who dropped some computer diskettes on the ground. The dependent variable was whether or not the shopper stopped to help pick up the diskettes (GuĂŠguen & de Gail, 2003).Notice that these participants were not ârecruited,â but the researchers still had to select them from among all the shoppers taking the stairs that day. It is extremely important that this kind of selection be done according to a well-defined set of rules that is established before the data collection begins and can be explained clearly afterward. In this case, with each trip down the stairs, the confederate was instructed to gaze at the first person he encountered who appeared to be between the ages of 20 and 50. Only if the person gazed back did he or she become a participant in the study. The point of having a well-defined selection rule is to avoid bias in the selection of participants. For example, if the confederate was free to choose which shoppers he would gaze at, he might choose friendly-looking shoppers when he was set to smile and unfriendly-looking ones when he was not set to smile. As we will see shortly, such biases can be entirely unintentional. Standardizing the ProcedureIt is surprisingly easy to introduce extraneous variables during the procedure. For example, the same experimenter might give clear instructions to one participant but vague instructions to another. Or one experimenter might greet participants warmly while another barely makes eye contact with them. To the extent that such variables affect participantsâ behaviour, they add noise to the data and make the effect of the independent variable more difficult to detect. If they vary across conditions, they become confounding variables and provide alternative explanations for the results. For example, if participants in a treatment group are tested by a warm and friendly experimenter and participants in a control group are tested by a cold and unfriendly one, then what appears to be an effect of the treatment might actually be an effect of experimenter demeanor. When there are multiple experimenters, the possibility for introducing extraneous variables is even greater, but is often necessary for practical reasons.
It is well known that whether research participants are male or female can affect the results of a study. But what about whether the experimenter is male or female? There is plenty of evidence that this matters too. Male and female experimenters have slightly different ways of interacting with their participants, and of course participants also respond differently to male and female experimenters (Rosenthal, 1976). For example, in a recent study on pain perception, participants immersed their hands in icy water for as long as they could (Ibolya, Brake, & Voss, 2004). Male participants tolerated the pain longer when the experimenter was a woman, and female participants tolerated it longer when the experimenter was a man. Researcher Robert Rosenthal has spent much of his career showing that this kind of unintended variation in the procedure does, in fact, affect participantsâ behaviour. Furthermore, one important source of such variation is the experimenterâs expectations about how participants âshouldâ behave in the experiment. This outcome is referred to as an experimenter expectancy effect (Rosenthal, 1976).For example, if an experimenter expects participants in a treatment group to perform better on a task than participants in a control group, then he or she might unintentionally give the treatment group participants clearer instructions or more encouragement or allow them more time to complete the task. In a striking example, Rosenthal and Kermit Fode had several students in a laboratory course in psychology train rats to run through a maze. Although the rats were genetically similar, some of the students were told that they were working with âmaze-brightâ rats that had been bred to be good learners, and other students were told that they were working with âmaze-dullâ rats that had been bred to be poor learners. Sure enough, over five days of training, the âmaze-brightâ rats made more correct responses, made the correct response more quickly, and improved more steadily than the âmaze-dullâ rats (Rosenthal & Fode, 1963). Clearly it had to have been the studentsâ expectations about how the rats would perform that made the difference. But how? Some clues come from data gathered at the end of the study, which showed that students who expected their rats to learn quickly felt more positively about their animals and reported behaving toward them in a more friendly manner (e.g., handling them more). The way to minimize unintended variation in the procedure is to standardize it as much as possible so that it is carried out in the same way for all participants regardless of the condition they are in. Here are several ways to do this:
Another good practice is to arrange for the experimenters to be âblindâ to the research question or to the condition that each participant is tested in. The idea is to minimize experimenter expectancy effects by minimizing the experimentersâ expectations. For example, in a drug study in which each participant receives the drug or a placebo, it is often the case that neither the participants nor the experimenter who interacts with the participants know which condition he or she has been assigned to. Because both the participants and the experimenters are blind to the condition, this technique is referred to as a . (A single-blind study is one in which the participant, but not the experimenter, is blind to the condition.) Of course, there are many times this blinding is not possible. For example, if you are both the investigator and the only experimenter, it is not possible for you to remain blind to the research question. Also, in many studies the experimenter must know the condition because he or she must carry out the procedure in a different way in the different conditions. Placebo effect blocker. [Image Description]Record KeepingIt is essential to keep good records when you conduct an experiment. As discussed earlier, it is typical for experimenters to generate a written sequence of conditions before the study begins and then to test each new participant in the next condition in the sequence. As you test them, it is a good idea to add to this list basic demographic information; the date, time, and place of testing; and the name of the experimenter who did the testing. It is also a good idea to have a place for the experimenter to write down comments about unusual occurrences (e.g., a confused or uncooperative participant) or questions that come up. This kind of information can be useful later if you decide to analyze sex differences or effects of different experimenters, or if a question arises about a particular participant or testing session. It can also be useful to assign an identification number to each participant as you test them. Simply numbering them consecutively beginning with 1 is usually sufficient. This number can then also be written on any response sheets or questionnaires that participants generate, making it easier to keep them together. Pilot TestingIt is always a good idea to conduct a of your experiment. A pilot test is a small-scale study conducted to make sure that a new procedure works as planned. In a pilot test, you can recruit participants formally (e.g., from an established participant pool) or you can recruit them informally from among family, friends, classmates, and so on. The number of participants can be small, but it should be enough to give you confidence that your procedure works as planned. There are several important questions that you can answer by conducting a pilot test:
Of course, to answer some of these questions you will need to observe participants carefully during the procedure and talk with them about it afterward. Participants are often hesitant to criticize a study in front of the researcher, so be sure they understand that their participation is part of a pilot test and you are genuinely interested in feedback that will help you improve the procedure. If the procedure works as planned, then you can proceed with the actual study. If there are problems to be solved, you can solve them, pilot test the new procedure, and continue with this process until you are ready to proceed.
Image DescriptionsA comic of two stick figures talking. Person 1: Some researchers are starting to figure out the mechanism behind the placebo effect. Weâve used their work to create a new drug: A placebo effect blocker. Now we just need to run a trial. Weâll get two groups, give them both placebos, then give one the REAL placebo blocker, and the other aâŚ. wait. [The two people scratch their heads] Person 2: My head hurts. Person 1: Mine too. Here, want a sugar pill? [Return to Image] Media AttributionsAn established group of people who have agreed to be contacted about participating in research studies. A source of variation in which the experimenterâs expectations about how participants âshouldâ be have in the experiment. An experiment in which both the participants and the experimenters are blind to which condition the participants have been assigned to. A small-scale study conducted to make sure that a new procedure works as planned. |