McGraw-Hill/Irwin Copyright © 2011 by The McGraw-Hill Companies, Inc. All rights reserved. Choosing and Using Research Subjects

2 Population Large group including all potential subjects May be defined in many ways All children in day care Children in day care in a particular city Sample Small subgroup of subjects chosen from the population May need to define a subpopulation for study

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4 Goal is to apply results obtained from a sample to the population Generalization is the ability to apply findings from a sample to the population Random sample: A sample in which every member of the population has an equal chance of being chosen Ideal that is not often met Nonrandom sample: A sample from a specialized population (e.g., college students)

5 Internet research uses a nonrandom sample Participants are self-selected volunteers Participants know how to use computers Participants have access to computers Participants are Internet savvy Two ways to demonstrate the validity of Internet research Compare Internet with non-Internet results Compare Internet results with theoretical predictions Internet and non-Internet samples may not differ significantly May be a problem for sensitive issues

6 Animals obtained from a single supplier do not constitute a random sample Minor differences in a strain of rats my yield different results For example, drug effects Findings from one lab may not replicate in another due to differences between strains used

7 Random samples most crucial when you want to apply results directly to a population For example, predicting behavior from a survey or poll Most research in psychology seeks to apply results indirectly, making random sampling less crucial Factors other than sample affect generality of results How independent variables are manipulated Realism of experimental situation

8 Several factors affect how human participants are acquired The research setting Laboratory research: Likely to use a subject pool Field research Survey: Use one of several sampling techniques Field experiment Wait for participants to happen along Randomly assign participants to conditions Your research needs May need specialized sample for certain types of research Select participants based on some characteristic

9 Institutional policies Adherence to ethical guidelines Institutional rules on how participants can be recruited There may also be state or federal rules that must be followed

10 Ethical guidelines require that participation be voluntary Using volunteer participants may affect the internal and external validity of research Volunteer bias: Sample made up of volunteers is a biased sample

11 Maximum Confidence 1.Volunteers tend to be more highly educated than nonvolunteers 2.Volunteers tend to come from a higher social class than nonvolunteers 3.Volunteers are of a higher intelligence in general, but not when volunteers for atypical research (such as hypnosis, sex research) 4.Volunteers have a higher need for approval than nonvolunteers 5.Volunteers are more social than nonvolunteers

12 Considerable Confidence 1. Volunteers are more “arousal seeking” than nonvolunteers (especially when the research involves stress) 2. Individuals who volunteer for sex research are more unconventional than nonvolunteers 3. Females are more likely to volunteer than males, except when the research involves physical or emotional stress 4. Volunteers are less authoritarian than nonvolunteers 5. Jews are more likely to volunteer than Protestants; however, Protestants are more likely to volunteer than Catholics 6. Volunteers have a tendency to be less conforming than nonvolunteers, except when the volunteers are female and the research is clinically oriented Source: Adapted from Rosenthal & Rosnow, 1975.

13  Marcus and Schütz (2005) compared responders and nonresponders to an Internet survey  Respond higher in agreeableness and openness to new experiences than nonresponders  Low levels of openness to new experience related to fewer items completed  Compared to men, women are:  Less likely to volunteer for studies on sexual behavior  More likely to answer questions about sexuality  You should be aware that Volunteers and nonvolunteers may differ in important ways

14 Individuals interested in a topic more likely to volunteer for a study on that topic Individuals more likely to volunteer if they think research topic is important Individuals less likely to volunteer for aversive or stressful research Incentives for participation interact with personal characteristics to affect volunteering Nature of stimuli used affects volunteering Media coverage of research affects volunteering

15 Variables related to voluntary participation may affect value of your dependent variable Volunteerism may affect “inferred causality” which is closely related to internal validity A study by Rosenthal and Rosnow (1975) on volunteer bias and attitudes demonstrated inferred causality Volunteers’ disposition to respond to demand characteristics affected internal validity

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17 Volunteer bias may affect external validity Individuals who volunteer for certain types of research differ from nonvolunteers Empathic/sympathetic people more likely to volunteer People willing to volunteer for a study of prison life different from those unwilling to volunteer Volunteers more responsive to persuasive communication than nonvolunteers These differences limit ability to generalize results to general population

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19 Make your appeal very interesting Make your appeal as nonthreatening as possible Explicitly state the theoretical and practical importance of your research Explicitly state why the target population is relevant to your research Offer a small reward for participation

20 Have a high-status person make the appeal for participants Avoid research that is physically or psychologically stressful Have someone known to participants make the appeal Use public or private commitment to volunteering when appropriate

21 Research using deception is allowed under ethical guidelines Full disclosure of all aspects of an experiment may not be feasible Participants may have to be deceived about the nature of an experiment Deception raises several issues that you must consider Reasons for using deception: Creating interesting situations not likely to occur naturally Certain behaviors can only be studies if a person is caught off guard

22 Active deception Misrepresentation of the purpose of the research False statements about the identity of the researcher False promises made to the participant Violations of a promise of anonymity Misleading statements about equipment and procedures Use of pseudosubjects False diagnoses and other reports False interaction Using placebos or secret administration of drugs Misleading settings and behavior of the experimenter

23 Passive deception Doing unrecognized conditioning Provoking and secretly recording negative behavior of participants Making concealed observations Doing unrecognized participant observation Using projective techniques and other personality tests

24 Deceived participants act differently from nondeceived participants in later study Deceived participants less likely to volunteer for later study Deceived participants may feel duped and experience a loss of self-esteem Participants may find out something negative about themselves

25 Deception may violate requirements of informed consent Deceived participants may be suspicious of future research participation

26 Role Playing Fully informed participants are asked to act as though they were exposed to an experimental treatment Obtaining Prior Consent to be Deceived Participants told that some experiments may involve deception Only those agreeing to deception are used in deception research Debriefing Inform participants of deception AFTER participation

27 Make a full disclosure of purposes of research Give a complete description of and justification for the deception Discuss the problem of perseverance Provide a convincing argument for the need for deception Tell participants that not only is false feedback from a bogus test false, but that the test itself was bogus

28 Demonstrate bogus equipment, or show participants that actual responses were never seen by the experimenter Have participants observe a subsequent session showing deception in action Make the individual an active participant in the research (e.g., a confederate) Give participants practice detecting deception Be honest and sincere during debriefing Providing thorough debriefing leaves participants in a positive frame of mind

29 Animal research has made considerable contributions to science You must decide which animals to use May be driven by requirements of research You may use animals for procedures not allowed with humans Still bound by ethical requirements You must decide which animals to use You must decide how to acquire animals Animal subjects must be treated humanely and ethically

30 Generality of animal research data Results from animal research may not generalize to humans Many results do generalize to humans Generalization to humans need not be a requirement The animal rights movement Questions the use of animals in research Long history of concern over role of animals in research Some criticisms lack validity This issue seems to be cooling down some Animal rights advocates are genuinely interested in protecting the welfare of animals

31 In Vitro methods Substituting tissue samples for living animals May be adequate for early phases of drug testing Impractical for behavioral research Cannot study the effects of environmental variables and manipulations of the brain Computer Simulation Mathematical model of behavior programmed into a computer and behavior is simulated Research on living animals still needed to develop the computer models