- Define different methods of observation in conducting psychological research
- Understand how experiments are conducted


[SLIDE 1]

Scientists have devised controlled ways of studying people. Nearly all kinds of psychological research involve observation of the behavior of samples of populations, but some methods, such as the case study, the survey, and naturalistic observation, are mainly descriptive in nature.

A case study is a carefully drawn biography that may be obtained through interviews, questionnaires, and psychological tests. This can be used to collect information about individuals and small groups. Many case studies are clinical; that is, they are descriptions of a person's psychological problems and how a psychologist treated them. Case studies are sometimes used to investigate rare occurrences. They are subject to inaccuracies, however, because we find gaps and factual errors in people's memories. People may also distort their past to please or to antagonize the interviewer.

Interviewers may also have certain expectations and may subtly encourage participants to fill in gaps in ways that are consistent with these expectations. Psychoanalysts, for example, have been criticized for guiding people who seek their help into viewing their own lives from the psychodynamic perspective. No wonder, then, that many people provide "evidence" that is consistent with psychodynamic theory -- for example, blaming their parents' inept handling of toilet training as the source of compulsive neatness. Interviewers of any theoretical viewpoint may subtly steer people towards saying what they want to hear. 


[SLIDE 2]

Just as computers and pollsters predict election results and report national opinion on the basis of scientifically selected samples, psychologists conduct surveys to learn about behavior and mental processes that cannot be observed in the natural setting or studied experimentally. A survey is a method of scientific investigation in which a large sample of people answer questions about their attitudes or behavior.

Psychologists conducting surveys may employ questionnaires and interviews or examine public records. One of the advantages of the survey is that by distributing questionnaires and analyzing answers with a computer, psychologists can study many thousands of people at a time. One of the best-known surveys, the so-called Kinsey reports, provided surprising information about people's sexual behavior during the middle of the 20th century, a time of widespread sexual repression in the United States. The nation was shocked to hear that masturbation was virtually universal in this sample of men in a day when masturbation was still widely thought to impair health. At the time, it was also widely believed that nearly all single women were virgins. Yet Kinsey found that about one in three women who remained single at age 25 reported having engaged in sexual intercourse.

Surveys, like case studies, also have sources of inaccuracy. People may recall their behavior inaccurately or deny or lie about it. Similar problems may occur when interviewers and the people surveyed are from different ethnic or socioeconomic backgrounds. Other people may falsify attitudes and exaggerate problems to draw attention to themselves or to intentionally foul up the results.  


[SLIDE 3]

Naturalistic observation is a scientific method in which organisms are observed in their natural environments. This method is used to observe people in their natural habitats every day. Naturalistic observation allows psychologists and other scientists to observe behavior where it happens or "in the field." Observers use unobtrusive measures to avoid interfering with the behaviors they are observing.


[SLIDE 4]

Once psychologists have observed the behavior of their samples, they often use correlation to try to answer questions such as, are people with higher intelligence more likely to do well in school? The correlational method is a mathematical method of determining whether one variable increases or decreases as another variable increases or decreases. This allows psychologists to investigate whether an observed behavior or a measured trait is related to, or correlated with, another.

Consider the variables of intelligence and academic performance. These variables are assigned numbers such as intelligence test scores and academic averages. Then the numbers are mathematically related and expressed as a correlation coefficient which is a number between +1.00 and -1.00 that expresses the strength and direction, either positive or negative, of the relationship between two variables. The correlation coefficient is often represented as "r".

Studies report positive correlations between intelligence test scores and academic achievement, as measured, for example, by grade point averages. That is, the higher people score on intelligence tests, the better their academic performance is likely to be. While intelligence test scores tend to be positively correlated with academic achievement, other factors also contribute to academic success. These include early learning opportunities, desire to get ahead, self-discipline, ability to manage stress, and belief in one's ability to succeed.


[SLIDE 5]

The preferred method for answering questions about cause and effect is by conducting an experiment. This is a scientific method that seeks to confirm cause-and-effect relationships by introducing independent variables and observing their effects on dependent variables.

For example, in an experiment, a group of participants obtains a treatment, such as a dose of alcohol, a change in room temperature, or perhaps an injection of a drug. The participants are then observed to determine whether the treatment makes a difference in their behavior. Experiments allow psychologists to control the experiences of participants and draw conclusions about cause and effect. A psychologist may theorize that alcohol leads to aggression because it reduces fear of consequences or because it energizes the activity levels of drinkers, but the theory needs to be tested. In one approach, the psychologist may devise a treatment in which participants receive various doses of alcohol and the outcomes on their behavior are measured. 


[SLIDE 6]

In an experiment to determine whether alcohol causes aggression, participants are given an amount of alcohol and its effects are measured. In this case, alcohol is an independent variable, as it is a condition in the scientific study that is manipulated so that its effects may be observed. The independent variable of alcohol may be administered at different levels, or doses, from none or very little to enough to cause intoxication or drunkenness.

The measured results, or outcomes, in an experiment are called dependent variables, or the measure of an assumed effect of an independent variable. In other words, the presence of dependent variables presumably depends on the independent variables. In an experiment to determine whether alcohol influences aggression, aggressive behavior would be a dependent variable. Other dependent variables of interest might include sexual arousal, visual–motor coordination, and performance on cognitive tasks such as math problems. We could also use a second independent variable such as social provocation. For example, we could insult some participants but not others and see whether insults affect their level of aggression. This method would allow us to study how two independent variables -- alcohol and social provocation -- affect aggression, by themselves and together.


[SLIDE 7]

Ideal experiments use experimental groups and control groups. Participants in experimental groups obtain the treatment. Members of control groups do NOT obtain the treatment. Every effort is made to ensure that all other conditions are held constant for both groups. This method enhances the researchers' confidence that the outcomes of the experiment are caused by the treatments and not by chance factors or chance fluctuations in behavior. For example, in an experiment on the effects of alcohol on aggression, members of the experimental group would ingest alcohol, and members of the control group would not. The researcher would then measure how much aggression was shown by each group.


[SLIDE 8]

People tend to act in stereotypical ways when they have been drinking alcohol. For instance, men tend to become less anxious in social situations, more aggressive, and more sexually aroused. To what extent do these behavior patterns reflect the direct effects of alcohol on the body, and to what extent do they reflect people's beliefs about the effects of alcohol? 

One experiment on the effects of alcohol on aggression reported that men at parties where beer and liquor were served acted more aggressively than men at parties where only soft drinks were served. But participants in the experimental group knew they had drunk alcohol, and those in the control group knew they had not. Aggression that appeared to result from alcohol might not have reflected drinking per se. Instead, it might have reflected the participants' expectations about the effects of alcohol.

In medicine, physicians sometimes give patients placebos when the patient insists on having a medical cure but the physician does not believe that medicine is necessary. A placebo is a bogus treatment that has the appearance of being genuine. In other words, it is a fake treatment, such as sugar pills. When patients report that placebos have helped them, it is because they expected the pills to be of help and not because of the biochemical effects of the pills. Well-designed experiments control for the effects of expectations by creating conditions under which participants are unaware of, or blind to, the treatment. Being blind in experimental terminology refers to the subject being unaware of whether or not he has received treatment. 


[SLIDE 9]

Placebos are one way of keeping participants blind as to whether they have received a particular treatment. Yet researchers may also have expectations. They may be "rooting for" a certain treatment outcome, a phenomenon known as experimenter bias. It is useful if the people measuring the experimental outcomes are unaware of which participants have received the treatment. Studies in which neither the participants nor the experimenters know who has obtained the treatment are called double-blind studies. Neither the participants nor the researchers know who is receiving the real treatment in many experiments.

The Food and Drug Administration requires double-blind studies before it allows the marketing of new drugs. The drug and the placebo look and taste alike. Experimenters assign the drug or placebo to participants at random. Neither the participants nor the observers know who is taking the drug and who is taking the placebo. After the final measurements have been made, a neutral panel judges whether the effects of the drug differed from those of the placebo.  


[SLIDE 10]

In an illustrative double-blind study on the effects of alcohol on aggression, Alan Lang and his colleagues pre-tested a highball of vodka and tonic water to determine that it could not be discriminated by taste from tonic water alone. They then recruited college men who described themselves as social drinkers to participate in the study. Some of the men drank vodka and tonic water. Others drank tonic water only. Of the men who drank vodka, half were misled into believing they had drunk tonic water only. Of those who drank tonic water only, half were misled into believing their drink contained vodka. Thus, half the participants were blind to their treatment.

Experimenters defined aggression as pressing a lever that participants believed would deliver an electric shock to another person. The researchers who measured the men's aggressive responses were also blind concerning which participants had drunk vodka. The research team found that men who believed that they had drunk vodka responded more aggressively by selecting a higher level of shock in response to a provocation than men who believed that they had drunk tonic water only. The actual content of the drink was immaterial. That is, the men's belief about what they drank affected their behavior more than what they actually consumed.