Bonus Appendix 1 | Research Design Explained

Bonus Appendix C: Conducting a Study

Planning Your Procedures

You have reviewed the literature, developed a hypothesis, operationalized your variables, and given sound reasons for testing your hypothesis. However, your preliminary work is still not done. You must now decide exactly what specific actions you will take. In other words, although you probably have decided on the general design (such as a simple experiment or a 2 X 2), your plan is not complete until each detail has been thought through and written down.

You should write down exactly what procedures you will follow. For example, what instructions, word for word, will you give participants? Where will you test them? Will participants be run in groups or individually? In answering these questions, you must take into account issues of validity. However, your paramount concern must always be ethics. You do not have the right to harm another.

Ethical Considerations: Human Research

Ethics should be the foundation of your research plan. Therefore, you should read Appendix A (Ethics) before conducting a study.

In addition to reading Appendix A, you must be extremely careful not to harm your participants. Ideally, your participants should feel just as well when they leave the study as they did when they began the study. Unfortunately, even in the most innocuous studies, protecting your participants from discomfort is much easier said than done.

Weighing the Risks

Realize that any experience may be traumatic to some participants. Trauma can occur from things you would never think of as being traumatic. Because any study has risks and because you will not know all of the risks, do not run a single participant without your professor’s permission.

To begin to sensitize yourself to the risks involved in your proposed study, list the 10 worst things that could possibly happen to participants. If you are using human participants, be aware that not all participants will react in the same way. Some may experience trauma because the study triggers some painful memory. Some participants may feel bad because they think they did poorly. Other participants may feel bad because they think their behavior ruined your study. Realize that some of your participants may be mentally unbalanced and any attack on their self-esteem might lead to disastrous consequences. Because participants are often fragile, you should list some serious consequences in your worst-case scenario.

Reducing Risks

Because any study has the potential for harm, the possibility of severe consequences does not mean that your professor will not allow you to do the study. However, you and your professor should think about ways to minimize the risks.

Screening Participants

One method of minimizing risks is to screen out “vulnerable participants.” For instance, if there is any reason to believe that your study may increase heart rate or blood pressure, you may want to make sure that only people in good health participate in your study. If your study might harm people with low self-esteem, you may want to use only well-adjusted participants who have high levels of self-esteem. Therefore, you might give a measure of self-esteem to potential participants to eliminate those with low self-esteem.

Informed Consent

Not only should you screen participants, but you should also let participants screen themselves. That is, participants should be volunteers who give their informed consent: They should know what the study is about before volunteering for it.

How informed is informed consent? Very informed, when it comes to telling participants about any unpleasant aspect of the study. If participants are going to get shocked or exposed to loud noises or extreme cold, they should be informed of this before they volunteer. Consequently, if your study does involve unpleasantness, you may have difficulty getting participants to volunteer.

Informed consent is considerably less informed when it comes to more innocuous aspects of the study. After all, the study would be ruined if participants knew everything that would happen (and why it happened) before it happened. So, although participants are usually told the truth, they are not always told the whole truth. For example, a memory experiment’s description would mention that participants have to memorize words, but might omit the fact that the researcher is looking at the order in which facts are recalled or that there is a surprise recall of all the lists at the end of the study.

Because participants are not fully informed about your study, there may be some things about it that they dislike. For example, suppose a participant finds the task too difﬁcult or finds it upsetting to try the surprise recall task. What can you do?

One protection against these unexpected problems is to make sure participants understand that they can quit the study at any time. So, before the participants begin your study, tell them that if they find any aspect of the study uncomfortable, they can and should escape this discomfort by quitting the study. Assure them that it is their duty to quit if they experience discomfort and that they will still get full credit.

Modifying the Study

You have seen that you can minimize ethical problems by letting participants know what they are in for and by letting participants gracefully withdraw from the study. You should also minimize harm by making your study as humane as possible. You can make your study more ethical by reducing the strength of your treatment manipulation, carefully selecting stimulus materials, and by being a conscientious researcher.

Reducing the Treatment Strength

Although using extreme levels of your predictor variable may help you get a significant change in the criterion variable, extreme levels may harm your participants. For example, 24 hours of food deprivation is more likely to cause hunger than 12 hours. However, 24 hours of deprivation is more stressful to the participant. If you plan an unpleasant manipulation, remember your participants’ welfare and minimize the unpleasant consequences as much as possible. Consider using levels of the predictor variable that are less severe than you originally intended.

Modifying Stimulus Materials

By modifying your stimulus materials, you may be able to prevent them from triggering unpleasant memories. For instance, if you were interested in the effects of caffeine on memory for prose, you would not want the prose passage to cover some topic like death, divorce, alcoholic parents, or rape. Instead, you would want to use a passage covering a less traumatic topic such as sports. If the sports article referred to someone’s death or hospitalization, you might want to delete that section of the article.

The Conscientious Researcher

Often, it is not the study that causes ethical problems, it is the researcher’s arrogance. For example, an arrogant researcher may rush through research sessions providing only superficial explanations and almost no time for questions and feedback. Although we know of a few participants who were hurt as a direct result of a research manipulation, we know of many more who were hurt because the researcher treated them like dirt. To ensure that you are sensitive, courteous, and respectful to all of your human participants, you should do two things.

First, when scheduling your research sessions, make sure you leave a 10-minute gap between the end of one session and the beginning of the next session. Some investigators feel that, like a physician, they should efficiently schedule people one after another. Their attempt at efficiency results in participants having to wait for the investigator, the investigator having to rush through the formalities of greeting participants, or—even worse—the investigator rushing through debriefing. Thus, the overly efficient investigator, like the overly efficient physician, is seen as unconcerned. Although this conduct does not become physicians, it is intolerable for psychological researchers. After a research participant has given an hour of his or her time, you should be more than willing to answer any questions the participant has. Furthermore, if you rush through greeting or debriefing each participant, the participants will see you as uncaring. Consequently, participants will be less likely to tell you about any psychological discomfort they felt and less likely to accept any aid you might offer. Thus, the first step is to walk, rather than to run, participants through your study.

Second, give the participants power. That is, allow participants to rate your study on a scale such as the one in Table 1–1 (below). Give each participant’s rating sheet to your instructor. Following this simple procedure helps you to be a conscientious and courteous researcher.

Table 1–1

Sample Debriefing Rating Scale

Being a participant in psychology studies should provide you with a firsthand look at research. On the scale below, please indicate how valuable or worthless you found being in today’s study by circling a number from +3 to –3.

WORTHLESS: –3 –2 –1 +1 +2 +3 :VALUABLE

If you wish to explain your rating or to make comments on this study, either positive or negative, please do so below.

NOTE: This scale is a slightly modified version of a scale that has been used at The Ohio State University.

Debriefing

Although you should try to anticipate and prevent every possible bad reaction a participant may have to being in your study, you will fail. . Inevitably, your procedures will still cause some unpleasantness. After the study is over, you should try to remove this unpleasantness by informing participants about the study, reassuring them that their reactions were normal, and expressing your appreciation for their participation.

You should also listen to participants and be sensitive to any unexpected, unpleasant reactions to your study. By being a good listener, you should be able to undo any damage you have unwittingly done. This process of informing your participants about the study and removing any harm done is called debriefing. Occasionally, ordinary debriefing will not undo the harm caused to the research participant. In those cases, there are several steps you may take to alleviate distress. For participants who are upset with their responses, you should ask them whether they want you to destroy their data. For participants that you cannot calm down, you should take them to talk to a professor, counselor, or friend—even if this means canceling a research session you had scheduled.

In summary, you should be very concerned about ethics. Since ethics involves weighing the costs of the study against the potential benefits, you should do everything you can to minimize the risk of participants becoming uncomfortable. If, despite your efforts, a participant experiences discomfort, you should try to reduce that discomfort during debriefing.

Ethical Considerations: Animal Research

With animal participants, you incur the same responsibilities that you did with human participants—you must protect animal participants from undue stress and discomfort. In many ways, you have even more responsibility to animal participants because they depend on you for their mere existence. You must keep them fed, clean, warm, and comfortable—24 hours a day. To fulfill your responsibility to animal participants, you must follow APA’s guidelines for proper housing, food and water, and handling (see Appendix A).

Furthermore, because your animal subjects n have neither the power to give their informed consent, nor the power to quit the study, you must carefully question the value of your study. Ask yourself and your professor this question: “Is the potential knowledge gained from the study worth the cost to the animals?” Finally, if you must euthanize (kill) your animal participants at the end of your study, follow APA’s guidelines to ensure that you euthanize your animals in the most humane way.

Maximize the Benefits: The Other Side of the Ethics Coin

We have discussed ways of minimizing harm to participants. However, minimizing harm is not enough to ensure that your study is ethical. For your study to be ethical, the potential benefits must be greater than the potential harm. Thus, an extremely harmless study can be unethical if the study has no potential benefits. In other words, just as you owe it to your participants to reduce potential harm, you owe it to your participants to maximize the potential benefits of your study. You maximize that potential by making sure your study provides accurate information. To provide accurate information, your study needs to have power and validity.

Power Is Knowledge

One of the most serious obstacles to obtaining accurate information is lack of power. Remember, null results do not prove the null hypothesis. They only make people wonder about the study’s power. There is no point in doing a study that is so powerless that it will lead to inconclusive, null results.

To have power, you should use a strong manipulation, a sensitive dependent measure, well-standardized procedures, a sensitive design, and enough participants.

Sample Size: There Is Power in Numbers

Perhaps your most important obstacle to finding a significant effect is a lack of participants. As a general rule, you should have at least 16 participants in each group.[1] However, the number of participants you need in each group will be affected by the sensitivity of your design, the heterogeneity of your participants, the number of observations you get from each participant, the size of the difference you expect to find between conditions, and the sensitivity of your dependent measure.

If you have a within-subjects design, a reliable and sensitive dependent variable, and expect a rather large difference between your conditions, you may be able to use fewer than 16 participants per group. If, on the other hand, you are using a simple, between-subjects design, heterogeneous participants, a manipulation that may have little effect, and a relatively insensitive dependent measure, you may want at least 100 participants per condition.

Hunting for Participants

Getting enough participants to have enough power can be a challenge, especially if you are at a small school. However, even at a large school, getting enough students to volunteer to be in your study can be difficult.

Using a Department Participant Pool

Your institution may, however, have made it is easier for you to get enough participants. Many colleges strongly encourage students in introductory psychology courses to volunteer to be research participants. In fact, most psychological research used this participant recruitment strategy. If your school has such a pool of participants, count yourself among the blessed. All you have to do is ask your professor how to use the participant pool.

Enlisting Volunteers

If your school does not have a participant pool, an effective way of getting participants is to ask professors to request volunteers from their classes. Many professors will gladly recruit participants for you. Indeed, your main problem may be that professors may be too eager. For example, if students feel they must participate, then they are not volunteers and you have violated the principle of informed consent. Even if professors merely encourage students to participate by giving extra credit, you are on ethically shaky ground unless (a) you have, in your IRB application, explained that students may receive extra credit and (b) there is an alternative extra credit assignment for those students who choose not to participate in your study.

NonCollege Samples

But what if you do not want to use college students in your study? For example, suppose you want to study children or retirees? Alternatively, suppose you agree with the skeptics who claim that if you study college students, you cannot apply your results to normal people. Then, you might look beyond college classrooms for participants. However, we should warn you that getting real-world participants make take as much work and creativity as planning your study.

Children

If you want to study children, you may be able to take advantage of the “captive” audience approach. After all, most children have to go to school. However, obtaining access to those children may turn into a nightmare of red tape. You will have to obtain permission from all or many of the following: the school board, the superintendent, principal, teacher, parent, child, your professor, and university. If you are going to get these permissions in time for your study, you will need to plan ahead—and be very lucky.

Adults

Finding adult participants can be even more challenging than finding children. For example, one of your textbook’s authors wanted an adult population for her doctoral dissertation. Her first thought was to contact a major company and gain access to its employees. This tactic failed. Next, she tried to run a newspaper ad asking for volunteers. One newspaper refused to print it. Another would only run it in the “Personal” section. Thus, her appeal for participants appeared with ads for astrological advice, massage services, and people wanting dates. Although a few “volunteers” called, most wanted either a date or an obscene conversation. We do not recommend newspaper ads—especially if your goal is to get a representative sample of the adult population.

Older Adults The authors have had greater success recruiting elderly participants. Nutrition centers, retirement communities, friendship networks, and nursing homes have been fruitful sources of participants. In addition, we recommend the “grandmother connection”: having an older relative or friend introduce you to other prospective participants.

Obviously, finding human participants will take planning, perseverance, and luck. Once you contact prospective participants, you should explain your study to them. Before they participate, they must sign a permission form. Signing the permission form—called an informed consent form—indicates that the participant understands what the study is about and has voluntarily agreed to participate. If you properly design the form (by following the instructions on page 475 of Research design explained and following the model presented in Box A-2, page 476 of Research design explained), the informed consent form will protect both you and your participants—if your participants are college students who are 18 years old or older. If minors are participating in your study, you need to have separate forms for both the participants and their parents.

Animal Subjects

Our experiences with recruiting human participants might have increased your enthusiasm for animal research. In some ways, research with animal subjects is less stressful than doing research with human participants. You do not have to worry about permission slips, extra credit, or obscene phone calls. Consult with your instructor about obtaining animals for your research. Often, schools have rat colonies or purchase animals for student research.

Reducing Threats to Construct Validity

After ensuring that your study has adequate power, we would like to be able to tell you that you can take it easy and relax. Unfortunately, however, you cannot relax. Power is not your only concern when conducting psychological research. You must also ensure that the construct validity of your results is not destroyed by

1. Researchers failing to conduct your study in an objective, standardized way, or

2. Participants reacting to how they think you want them to react to the treatment, rather than reacting to the treatment itself.

Researcher Effects

If you use more than one investigator, you may be able to detect researcher effects by including the researcher as a factor in your design. In other words, randomly assign participants to both a condition and to a researcher. For example, if you have two treatment conditions (A and B) and two researchers (1 and 2), you would have four conditions: (1) A1, (2) B1 (3) A2 and (4) B2. After having Research 1 run conditions 1 and 2 and Researcher 2 run conditions 3 and 4, you could do an analysis of variance (ANOVA) using researcher as a factor to see whether different researchers got different results.[2]

Using ANOVA to detect researcher effects can be useful. However, there are at least two reasons why using ANOVA may not eliminate researcher effects. First, this statistical approach will only tell you if one researcher is getting different results than other researchers. If all your researchers are biased, you may not get a significant researcher effect. (Besides, if you are the only researcher, you cannot use researcher as a factor in an ANOVA.) Second, and more importantly, detecting researcher effects is not the same as preventing researcher effects.

To prevent researcher effects, you must address the three major causes of researchers failing to conduct studies in an objective and standardized manner. What are these causes? First, researchers may not know how to behave because you have not spelled out the exact procedures that the researchers should follow. Second, researchers may not follow those procedures. Third, the researchers may strongly expect participants to behave in certain ways.

Loose-Protocol Effect: The Importance of Developing a Protocol Often, the researchers are not behaving in an objective and standardized way because of the loose-protocol effect: The instructions are not detailed enough. Fortunately, the loose-protocol effect can avoided.

Before you start your study, carefully plan everything out. As a first step, you should write out a set of instructions that chronicles the exact procedure for each participant. These procedures should be so specific that by reading and following your instructions, another person could run your participants the same way you do.

To make your instructions specific, you might want to write a computer program based on these instructions. Since computers do not assume anything, writing such a program forces you to spell out everything down to the last detail. If you cannot program, just write the script as if a robot were to administer the study. Write out each step, including the actual words that researchers will say to the participants. The use of such a script will help standardize your procedures, thus reducing threats to validity.

Once you have a detailed draft of your protocol, give it a test run. For example, to ensure that you are as specific as you think you are, pretend to be a participant and have several different people run you through the study using only your instructions. See how the different individuals behave. This may give you clues as to how to tighten up your procedures. In addition, you should run several practice participants. Notice whether you change procedures in some subtle way across participants. If so, adjust your instructions to get rid of this variability.

At the end of your test runs, you should have a detailed set of instructions that you and any co-investigator can follow to the letter. To double-check your protocol, see Table 1–2 (below).

Table 1–2 ( To Table 1–3)

Protocol Checklist

How will you manipulate your treatment variables?

How will you measure your dependent (criterion) variables?

How many participants will you need?

Do you have your professor’s permission to conduct the study?

Do you have a suitable place to run your participants?

How will you get your participants?

If you are using animals, how will they be cared for?

What will you do with your animals after the study?

If you are using human participants, how will you make your sign-up sheets available to potential participants?

Have you included a description of the study (including how long it takes) on the sign-up sheet?

Will participants be rewarded for volunteering to be in your study (such as money or extra credit)?

If you are conducting an experiment, how will you assign participants to condition?

Have you written out a detailed research protocol?

If you are using human participants, have you developed a consent form?

If you are using human participants, have you written out the oral instructions you will give your participants?

If you are using human participants, have you written out what you will say during debriefing?

If volunteers are college students seeking extra credit, how will you notify professors about which students participated?

Will you inform participants about the outcome of your study? How?

Inspiring the Troops to Avoid Researcher Effects.

Unfortunately, even if you write out your protocol (procedures) in detail, you or your co-investigators may still fail to follow that protocol. To avoid the researcher failure-to-follow-protocol effect, you need to make sure that (a) All investigators know the procedures, and (b) that everyone is motivated to follow the procedures.

To make sure investigators learn the procedures, you should hold training sessions. Supervise investigators while they practice the procedures on each other and on practice participants.

Once researchers know the right way to run the study, the key is to make sure that they are motivated to run the study the same way every time. To increase researchers’ motivation to be consistent, you might have them work in pairs. While one researcher runs the participants, the other will listen in through an intercom or watch through a one-way mirror. You may even wish to record research sessions.

If your researchers still have trouble following procedures, you may need to automate your study. For instance, you might use a computer to present instructions, administer the treatment, or collect the dependent measure. Computers have the reputation for following instructions to the letter, so using a computer may help standardize your procedures. Of course, computers are not the only machines that can help you. Some of the machines that could help you give instructions and present stimuli include automated slide projectors, tape recorders, and videotape players. Countless other devices could help you record data accurately, from electronic timers and counters to noise-level meters.

Researcher-Expectancy Effect The final source of researcher bias is the researcher-expectancy effect: Researchers’ expectations are affecting the results. You can take three steps to prevent the researcher-expectancy effect:

1. Be very specific about how investigators are to conduct themselves. Remember, researcher expectancies probably affect the results by changing the investigator’s behavior rather than by causing the investigator to send a telepathic message to the participants.

2. Do not let the investigators know the hypothesis.

3. Do not let investigators know what condition the participant is in—making the investigator “blind.” Although making investigators blind is easiest in drug experiments where participants take either a placebo or the real drug, you can make investigators blind in nondrug experiments.

For example, if you present stimuli in booklets, you can design your booklets so that booklets for different conditions look very similar. In that way, an investigator running a group of participants might not know what condition each participant is in. For some studies, you may be able to use a second investigator who does nothing except collect the dependent measure. You could easily keep this second investigator in the dark about what treatment the participant received.

Review of Researcher Effects.

Whether you are the only investigator or one of a team of investigators, researcher effects may bias your results. Therefore, you should always try to prevent the loose-protocol effect, the failure-to-follow-protocol effect, and the researcher-expectancy effect.

Participant Effects

Unfortunately, in psychological research, you must be aware not only of researcher effects, but also of participant effects: Participants may see through the study and try to play along with what the investigator wants. Fortunately, there are various ways of preventing participants’ expectancies from biasing your results.

Preventing Participants’ Expectancies For starters, you might make your researcher blind to reduce the chance that the participant will get any ideas from the researcher. Thus, the techniques for reducing research effects that we just discussed may also reduce the effects of participants’ expectancies.

In addition, you may also be able to prevent participants’ expectancies by skillfully choosing your research design. In experimental investigations, for example, you might use a between-subject design rather than a within-subject design because participants who are exposed to only one treatment condition are less likely to guess the hypothesis than participants who are exposed to all treatment conditions.

Placebo Treatments

Another design trick you can use to reduce the impact of participants’ expectancies is to use placebo treatments. Placebo treatments prevent participants from knowing that they are in the “no-treatment” condition. Therefore, if you have comparison condition(s), use placebo treatment(s) rather than no-treatment condition(s). That way, all groups think they are receiving the treatment. Thus, any treatment effect you find will not be due to participants changing their behavior because they expect the treatment to have an effect.

Unobtrusive Recording

Participants are less likely to know the hypothesis if they do not know what you are measuring. Obviously, if, as in some field experiments, participants do not even know you are observing them, participants will not know what you are measuring. Thus, if your hypothesis is an obvious one, you might consider a field study. Although field studies lend themselves to unobtrusive recording, unobtrusive recording can even occur in a laboratory study. That is, participants will assume that if you are not in the room with them, you are not observing them. However, thanks to one-way mirrors and intercoms, you can monitor participants’ behavior from the next room.

Unobtrusive Measures

Even if the participant knows you are watching, the participant does not have to know what you are watching. That is, you can use unobtrusive measures. For example, you might put the participant in front of a computer and ask the participant to type an essay. Although the participant thinks you are measuring the essay’s quality, you could have the computer programmed to monitor speed of typing, time between paragraphs, number of errors made, and times a section was rewritten. In addition, you might also have tape-recorded and videotaped the participant, monitoring his or her facial expressions, number of vocalizations, and loudness of vocalizations.

Experimental Realism

Rather than trying to obscure or confuse participants as to the purpose of the study, you might try to prevent participants from thinking about the purpose of the study. One way to stop participants from thinking about the study’s purpose is to design a study that has a high degree of experimental realism: a study that involves participants in the task. Experimental realism means that participants are not constantly saying to themselves: “What does the researcher really want me to do?” or “If I were a typical person, how would I behave in this situation?” Note that experimental realism does not mean the study is like real life; it means that participants are engrossed in the task. As you know from video games, even an artificial task can be very high in experimental realism.

Ethics Summary

Before now, you might have been surprised to see experimental realism and other strategies for reducing participant effects in a section on ethics. However, you now know that planning an ethical study involves taking into account many factors. Not only must you ensure the safety of your participants, but you must also demonstrate the validity of your methods. To avoid overlooking an important ethical consideration, consult Table 1-2, Table 1-3 (below), Appendix A, and your professor.

Table 1–3

Research With Human Participants: An Ethics Checklist

Is a physically unpleasant stimulus going to be used in your study? If so,

1. Is this fact clearly stated

a. on the sign-up sheet?

b. on the consent form?

2. Have you considered alternatives that would be less unpleasant?

3. Have you limited the intensity of this stimulus?

4. Have you taken steps to reduce potential harm to your participants caused by a physically unpleasant stimulus?

Are you going to use stress of some sort (such as sense of insecurity or failure, assault upon values, fatigue, or sleep deprivation) in your study? If so,

1. Is this fact clearly stated

a. on the sign-up sheet?

b. on the consent form?

2. Have you considered alternatives that would be less stressful?

3. Have you limited the intensity of this stimulus?

4. Have you taken steps to reduce potential harm to your participants caused by a psychologically unpleasant stimulus?

What will you do if participants exhibit signs of harm (for instance, crying, disoriented behavior)?

Are you prepared to describe the purpose and nature of your study to your participants during debriefing?

Will you use deception in your study? If so, what will you tell participants during debriefing?

Are you aware that participants can quit your study at any time? If a participant does drop out, will you give your participants credit for participating? Is this fact stated on the informed consent form? Is this fact part of your instructions to the participants?

What educational gain do you think participants will obtain from participating in your study?

How will you ensure the confidentiality of each participant’s data?

Beyond the Proposal: The Pilot Study

Even after you have carefully designed your study, modified it based on comments from your instructor, and been given your professor’s go-ahead to run it, you may still want to run several participants (friends, family members, other members of the class) just for practice. By running practice participants, you will get some of the “bugs” out of your study. Specifically, by running and debriefing practice participants, you will discover

1. whether participants perceived your manipulation the way you intended;

2. whether you can perform the study the same way every time or whether you need to spell out your procedures in more detail;

3. whether you are providing the right amount of time for each of the research tasks and whether you are allowing enough time in between tasks;

4. whether your instructions were clear;

5. whether your cover story was believable;

6. whether you need to revise your stimulus materials;

7. how participants like the study; and

8. how long it takes you to run and debrief a participant.

In short, running practice participants helps you to fine-tune your study. Because running practice participants is so useful, many professional investigators run enough practice participants to constitute a small study—what researchers call a pilot study.

Conducting the Actual Study

The dress rehearsal is over. You have made the final changes in your procedures and your proposal. Now you are ready for the real thing—you are ready to conduct your study. This section will show you how.

Establishing Rapport

As you may imagine, some of your prospective participants may be apprehensive about the study. Participants often are not sure whether they are in the right place, or even whether the researcher is a Dr. Frankenstein.

To put your participants at ease, let them know they are in the right place, and be courteous. You should be both friendly and businesslike. The expert investigator greets the participant warmly, pays close attention to the participant, and seems concerned that the participant knows what will happen in the study. The expert investigator is obviously concerned that each participant is treated humanely and that the study is done professionally.

Being professional does not hurt how participants view you. Why? First, most participants like knowing that they are involved in something important. Second, some will view your professionalism as a way of showing that you value their time—which you should.

So, how can you exude a professional manner? Some novice investigators think that they appear professional when they act aloof and unconcerned. Nothing could be less professional. Participants are very turned off by a disinterested attitude. They feel that you do not care about the study and that you do not care about them.

To appear professional, you should be neatly dressed, enthusiastic, well-organized, and prompt. “Prompt” may be an understatement. You should be ready and waiting for your participants at least 10 minutes before the study is scheduled to begin. Once your participants arrive, concentrate exclusively on the job at hand. Never ask a participant to wait a few minutes while you socialize with friends.

What do you lose by being a “professional” investigator? Problem participants. If you seem enthusiastic and professional, your participants will also become involved in doing your study—even if the tasks are relatively boring. Thus, if you are professional in your manner and attitude, you will probably not even have to ask the participants to refrain from chatting throughout the study. Similarly, if you are professional, participants will stop asking questions about the study if you say, “I will explain the purpose at the end of the study.”

After you have established rapport, you need to give your participants instructions. To get participants to follow instructions to the letter, you might

1. be repetitive,

2. have participants read the instructions,

3. orally paraphrase those instructions,

4. run participants individually,

5. invite participants to ask questions, and

6. have participants demonstrate that they understand the instructions by quizzing them or by giving them a practice trial before beginning the study.

Once the study has begun, try to follow the procedure to the letter. Consistently following the same procedures improves power and reduces the possibility of bias. Therefore, do not let participants change your behavior by reinforcing or punishing you. For instance, imagine you are investigating long-term memory. You want to expose participants to information and then see what they can write down. However, if you do this, participants may be writing down information that is in short-term memory. Thus, you would not be assessing long-term memory. Therefore, you add a counting backwards task that should virtually eliminate all of the information from short-term memory. Specifically, in your memory study, participants are exposed to information, are supposed to count backwards from a number like 781 by 3s for 20 seconds, and then are asked to recall the information. Ideally, their recall will represent only what they have in long-term memory. Unfortunately, many participants will aﬁnd the counting task unpleasant, embarrassing, or simply an unwanted nuisance. Consequently, some participants will thank you for telling them they can stop; others will plead nonverbally for you to stop. Clearly, you cannot let any of these strategies stop you from making them count backwards for the full 20 seconds. If you vary your procedures from participant to participant based on each participant’s individual whims, your study will have questionable validity.

Debriefing

Once the study is over, you should debrief your participants. In debrieﬁng, you should ﬁrst try to ﬁnd out whether the participants suspected the hypothesis. Simply ask participants what they thought the study was about. Then, explain the purpose of your study.

If you deceived your participants, you need to make sure they are not upset about the deception. You also need to make sure that they understand why deception was necessary. Participants should leave the study appreciating the fact that there was one and only one reason you employed deception: It was the only way to get good information about an important issue.

Making sure participants accept your rationale for deception is crucial for three reasons. First, you do not want your participants to feel humiliated or angry. Second, if they get mad, they may not only be mad at you, but also at psychologists in general. Perhaps that anger or humiliation will stop them from visiting a psychologist when they need help. Third, the unhappy participant may spread the word about your deception, ruining your chances of deceiving other participants.

After explaining the purpose of the study, you should answer any questions the participants have. Although answering questions may sometimes seem like a waste of time, you owe it to your participants. They gave you their time, now it is your turn.

After participants’ questions and doubts have been dealt with, give them an opportunity to rate how valuable they felt the study was. Letting participants rate your study encourages you to be courteous to your participants, ( lets you know whether your study is more traumatic than you originally thought, and makes participants feel that you respect them because you value their opinions.

After participants rate your study, you should assure participants that their responses during the study will be kept conﬁdential. Tell them that no one but you will know their responses. Then, ask the participants not to talk about the study because it is still in progress. For example, you might ask them not to talk about the study until next week. Finally, you should thank your participants, escort them back to the waiting area, and say goodbye.

Protecting Data: Confidentiality

You might think that once a participant leaves the study, your responsibilities to that participant end. Wrong! You are still responsible for guaranteeing the participant’s privacy. Knowledge about a given participant is between you (the investigator) and the participant—no one else. Never violate this conﬁdentiality. To ensure conﬁdentiality, you should take the following precautions:

1. Assign each participant a number. When you refer to a given participant, always use the assigned number—never that participant’s name.

2. Never store a participant’s name and data in a computer—this could be a computer hacker’s delight.

3. If you have participants write their names on booklets, tear off and destroy the cover of the booklet after you have analyzed the data.

4. Store a list of participants and their numbers in one place and the data with the participants’ numbers on it in another place.

5. Watch your mouth. There is rarely a reason to talk casually about a participant’s behavior. Even if you do not mention any names, other people may guess or think they have guessed the identity of your participant. We realize that it is hard to keep a secret. But to talk freely about someone who participated in your study is to betray a trust. Furthermore, keeping secrets will, for many of you, be an important part of your professional role: Therapists, researchers, consultants, lawyers, and physicians all must keep their clients’ behaviors confidential.

[1] Having more participants will give you more power. Indeed, some (Cohen, 1990) would consider 64 participants per group to be a reasonable minimum. We have talked about minimums. Are there maximums? Could you have a design that was too powerful? Some would argue that, in some cases, researchers use so many participants that even the smallest of effects, no matter how practically and theoretically insignificant, would be statistically significant. However, having an overpowered design is rarely a problem for novice researchers.

[2] You may want to consult with your professor as to the type of ANOVA you should use. Experts argue about whether one should use a conventional ANOVA model or a “random effects” ANOVA model.