chapter 24 laboratory experiments, field experiments, and field studies

Chapter 24

Laboratory Experiments, Field Experiments, and

Field Studies

• Social scientific research can be divided into four categories: laboratory experiments, field experiments, field studies, and survey research.

• This breakdown stems from two sources: the distinction between experimental and nonexperimental research and that between laboratory and field research.

A Laboratory Experiment: Miller’s Studies of the Learning of Visceral Responses

• Miller’s work has shown that, through instrumental conditioning, the heartrate can be changed, stomach contractions can be altered, and even urine formation can be increased or decreased.

• Miller’s big problem was control. There are a number of other causes of changed heartrate—for example, muscular exertion. To control such extraneous variables, Miller paralyzed the rats with curare. But if the rats were paralyzed, what could be used as reward? They decided to use direct electrical stimulation of the brain.

A Field Experiment: Rind and Bordia’s Study on the Effects of a Server’s “Thank you” and Personaliz

ation on Restaurant Tipping

• In an upscale restaurant during the lunch period for five days. Fifty-one diners participated in the study. All servers were female.

• The independent variable was Impression and consisted of three levels: (1) the back of the diner’s bill either contained nothing, (2) the handwritten words “thank you,” or (3) the words “thank you” plus the server’s first name.

• Each level or condition of the independent variable was determined randomly for each dining party.

A Field Study: Newcomb’s Bennington College Study

• The influence of a college environment on students

• The independent variable can be said to be the social norms of Bennington College. The dependent variables were social attitudes and certain behaviors of the students.

Characteristics and Criteria of Laboratory Experiments, Field Experiments, and Field Studies

• Strengths and Weakness of Laboratory Experiments

• The laboratory experimenter can isolate the research situation from the life around the laboratory by eliminating the many extraneous influences that may affect the independent and dependent variables.

• In addition to situation control, laboratory experiments can ordinarily use random assignment and can manipulate one or more independent variables.

Strengths and Weakness of Laboratory Experiments

• Closely allied to operational strength is the precision of laboratory experiments. Precise laboratory results are achieved mainly by controlled manipulation and measurement in an environment from which possible “contaminating” conditions have been eliminated.

• The greatest weakness of the laboratory experiment is probably the lack of strength of independent variables. Since laboratory situations are, after all, situations that are created for special purposes, it can be said that the effects of experimental manipulations are usually weak.

Strengths and Weakness of Laboratory Experiments

• Although laboratory experiments have relatively high internal validity, they lack external validity.

• The stronger our confidence in the “truth” of the relations discovered in a research study, the greater the internal validity of the study.

Purposes of the Laboratory Experiment

• Laboratory experiments have three related purposes. First, they are a means of studying relations under “pure” and uncontaminated conditions.

• A second purpose should be mentioned in conjunction with the first purpose: the testing of predictions derived from theory, primarily, and other research, secondarily.

• A third purpose of laboratory experiments is to refine theories and hypotheses, to formulate hypotheses related to other experimentally or nonexperimentally tested hypotheses and, perhaps most important, to help build theoretical systems.

Purposes of the Laboratory Experiment

• The aim of laboratory experiments, then, is to test hypotheses derived from theory, to study the precise interrelations of variables and their operation, and to control variance under research conditions that are uncontaminated by the operations of extraneous variables.

The Field Experiment

• A field experiment is a research study conducted in a realistic situation in which one or more independent variables are manipulated by the experimenter under conditions as the situation will permit.

• The contrast between the laboratory experiment and the field experiment is not sharp: the differences are mostly matters of degree.

Strengths and Weaknesses of Field Experiments

• As compensation for dilution of control, the field experiment has two or three unique virtues. The effects of field experiments are often strong enough to penetrate the distractions of experimental situations. The principle is: The more realistic the research situation, the stronger the variables.

• Realism simply increases the strength of the variables. It also contributes to external validity, since the more realistic the situation, the more valid are generalizations to other situations likely to be.


• Another virtue of field experiments is their appropriateness for studying complex social and psychological influences, process, and changes in lifelike.

• Laboratory experiments are studied mainly for testing aspects of theories, whereas field experiments are suited both to testing hypotheses derived from theories and to finding answers to practical problems.


• Flexibility and applicability to a wide variety of problems are important characteristics of field experiments. The only two limitations are whether one or more independent variables can be manipulated, and whether the practical exigencies of the research situation are such that a field experiment can be done on the particular problem under study.


• As indicated earlier, the main weaknesses of field experiments are practical. Manipulation of independent variables and randomization are perhaps the two most important problems.

• One other weakness in field experimental situations is lack of precision. In other words, the dependent variable measures are often so inadequate they cannot pick up all the variance that has been engendered by the independent variables.

Field Studies• Field studies are nonexperimental scientific inquirie

s aimed at discovering the relations and interactions among sociological, psychological, and educational variables in real social structures.

• Anderson, Warner, and Spencer (1984) studied the inflation bias of job applicants. Tom and Lucey (1997) studied waiting time in checkout situations in supermarkets and customer satisfaction with the checker and the store.

• The field study investigator ordinarily manipulates no independent variables. Neither randomization nor experimental manipulation was possible.

Types of Field Studies

• Katz (1953) has divided field studies into two broad types: exploratory and hypothesis testing.

• Exploratory studies have three purposes: to discover significant variables in the field situation, to discover relations among variables, and to lay the groundwork for later, more systematic and rigorous testing of hypotheses.

Strengths and Weaknesses of Field Studies

• Field studies are in realism, significance, strength of variables, theory orientation, and heuristic quality. The variance of many variables in actual field settings is large, especially when compared to the variance of the variables of laboratory experiments.

• In a field situation there is usually so much noise in the channel that even though the effects may be strong and the variance great, it is not easy for the experimenter to separate the variables.

Strengths and Weaknesses of Field Studies

• Its most serious weakness, of course, is its nonexperimental character. Thus statements of relations are weaker than they are in experimental research.

• Another methodological weakness is the lack of precision in the measurement of field variables. Studies of organizations, for example, are mostly field studies, and the measurement of organizational variables well illustrates the difficulties.

• Other weakness of field studies are practical problems: feasibility, cost, sampling, and time.

Qualitative Research

• One area within field studies is qualitative research. However, qualitative research is different since it does not rely on the use of numbers or measurements.

• There are areas for research where quantitative approaches cannot adequately capture the appropriate information.

• The term “qualitative research” is used here to refer to social and behavioral research based on unobtrusive field observations that can be analyzed without using numbers or statistics.


• The participants in the qualitative research studies may not be aware that they are being observed or studied. How much the participant is actively involved in the research process varies. Unlike single-subject or time-series research, the participant is unaware that any measurements are taken at all.

• Qualitative research is a field study because it is conducted in the field where the participants are behaving naturally.

Qualitative Research• Qualitative research has several advantages

over quantitative research. Qualitative research uses direct observation and semistructured interviewing in real-world settings.

• The researcher may make a number of adjustments during the observations. The researcher may even develop new hypotheses during the research process. Qualitative research is naturalistic, participatory, and interpretive.

Qualitative Research• Quantitative research seldom deviates from the

research plan. Qualitative research, on the other hand, is very flexible.

• Another area of vulnerability is experimenter bias. The qualitative researcher must be extra careful in guarding against viewing situations with a personal bias. However, qualitative researchers state that the unobtrusive involvement and natural blending of the observer into the environment reduces the amount of disruption in the setting and group under study.

Qualitative Research• The well-trained observer can acquire

perceptions of the participants’ behavior from different points of view.

• In qualitative research, the determination of sample size can be done near the end of the study instead of at the beginning. Sample size determination isn’t as important to the qualitative researcher. A rule in qualitative research is that the greater the number of interviews with each participant, the less the need for more participants.

Qualitative Research• The design of qualitative research usually uses an

unobtrusive observer or a participant observer. As an unobtrusive observer the researcher makes passive observations and tries to avoid responding to the participant in any way. No variables are manipulated; the researcher just lets natural events occur.

• In the participant-observer situation, the researcher becomes a part of the environment being studied. One feature of the participant-observer form is that the researcher can see the effect of manipulating his or her own behavior. Hence, occasionally, qualitative designs can resemble a natural experiment.


• Since diaries, recordings, and descriptions are taken from the people under study in their natural environment, ethical issues are very important. In particular, the confidentiality of records and information needs to be kept strictly secure.

Qualitative Research• Creswell (1998) pointed out that there are five differ

ent traditions within qualitative research. He compares and critiques biography, phenomenology, ground theory, ethnography, and case study. He also provided descriptions of seven different areas. Among the categories are Feminist Research, Action Research, and Qualitative Evaluation Research.

• With Feminist Research the focus is on the improvement of women’s needs, interests, experiences, and aims. Action Research involves the joint effort of the researcher and participant in bring about a change. Qualitative Evaluation Research deals with stories and cases studies.


• Padgett (1998) lays out three forms for doing both quantitative and qualitative research in one way. The combination of the two methods—qualitative and quantitative—is called multimethod research.

Qualitative Research• The first of the three ways of doing multimethod res

earch is to start the research as qualitative and finish it as quantitative. The qualitative method is used to explore and identify the ideas, hypotheses, and variables, of interest to the researcher. This would be done through direct observation, interviewing, or focus groups. The concepts derived from the qualitative portion of the study can then be studied through the use of quantitative methods and hypothesis testing. The generalizability of the concepts and hypotheses tested through quantitative research can gain more credibility by obtaining a better link to the real world.


• The second way of doing multimethod research is to use the quantitative method first, followed by the qualitative method. Qualitative methods could help provide insight and information concerning questions that were unanswered or unanswerable by the quantitative study.


• In the third mode of multimthod research, both qualitative and quantitative approaches are used simultaneously. Such studies can have one method more dominant than the other. When this happens, one method—the less dominant one—is “nested” within the other—the dominant one. The less dominant one is said to supplement but not alter the dominant one to the study.

chapter 24 laboratory experiments, field experiments, and field studies

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