Understanding Experimental Science: Observations to Predictions

1. :: Slide 1 :: :: Slide 2 :: Science stems from the empirical movement and thus observation, as well as measurement and description are crucial. The deterministic assumptions of science lead scientists to believe that if they can understand why a phenomenon occurs, then they will also be able to predict the conditions under which it will occur again. This gives us the ability to control our environment. Researchers must measure the phenomenon under study. For example, in studying the effectiveness of muscle relaxation techniques in reducing anxiety, a psychologist must first develop a means of measuring anxiety. :: Slide 3 :: :: Slide 4 :: Psychologists form hypotheses about how variables interact. A hypothesis is a tentative statement about the relationship between 2 or more variables. Variables are the things that are observed or controlled in a study. The purpose of an experiment is to find out how one variable, let’s call it X, affects another variable, which we’ll call Y. Information gathered by scientists may be of some practical value in helping to solve problems in schools, businesses, mental health centers, etc. :: Slide 5 :: :: Slide 6 :: Theories are attempts to explain phenomena. They are the product of inductive logic. Hypotheses are derived from theories to be applied to a specific, testable example. They are the product of deductive logic. Research is a catch-all heading which describes the myriad ways in which hypotheses can be tested. Hypothesis: Students who study over a span of 3 weeks before a test perform better than those who wait until the night before. Method: Give questionnaire to students on when they study. Data Collection: Collect questionnaires and test scores. Analysis: Correlate questionnaire with test scores. Report the findings: Students who studied over a multiple week period performed better on tests than those who crammed the night before.

2. :: Slide 7 :: :: Slide 8 :: The independent variable is a condition or event manipulated by experimenter. The dependent variable is an aspect of behavior thought to be affected by the independent variable. The experimental group consists ofparticipants who receive special treatment. The control group consists of similar subjects who do not receive treatment given to experimental group. Extraneous variables are factors besides independent variables that might affect the dependent variables, and need to be controlled. An example of experimental research would be the testing of morphine for effectiveness using analgesia – the absence of pain – as the dependent variable. The control group allows the researcher to isolate the effects of the independent variable – since the two groups are alike in every way except for the variation of the independent variable, any difference between the groups can be attributed to the independent variable. :: Slide 9 :: :: Slide 10 :: Which one of these is the dependent variable? Click to see answer. The amount eaten by the rats is the dependent variable. The caloric content is food is the independent variable determining the amount eaten by the rats. Sometimes, a single group can be used for both experimental and control conditions…for example, you might study the effects of having the radio on when people work on an assembly line…you’d collect data from the same group of workers twice, once with the radio on and once with it off. :: Slide 11 :: :: Slide 12 :: Researchers can also manipulate more than one IV to see what the combined effect is. Sometimes, the effect of one variable depends on the effect of another. For example, you might find that having the radio on increases productivity in workers, but only in the morning. In this example, time of day interacts with the effects of the radio. Researchers can also use more than one dependent variable in a single study to get a more complete picture of the effect of the independent variable. For example, we might measure not only number of pieces workers finish when the radio is allowed to be on while they work, but also worker satisfaction, absenteeism, and attitude. Having 1 day less a month absenteeism might make up for a slight decrease in productivity.

3. :: Slide 13 :: :: Slide 14 :: The power of the experimental method lies in the ability to draw conclusions about cause-and-effect relationships from an experiment. No other research method has this power. Experimental research does, however, have limitations. Experiments are often artificial; researchers have to come up with contrived settings so that they have control over the environment. Some experiments cannot be done because of ethical concerns. For example, you would never want to malnourish infants on purpose to see what the effects are on intelligence. Others cannot be done because of practical issues – there’s no way we can randomly assign families to live in urban vs. rural areas so we can determine the effects of city vs. country living. A positive correlation occurs when two or more variables vary in the same pattern. An example would be number of cigarettes smoked and blood pressure reading. :: Slide 15 :: :: Slide 16 :: A negative correlation occurs when two or more variables show patterns of variation directly opposite to one another. An example would be amount of cocaine ingested and number of hours slept in the last 24 hours. The correlation coefficient is a numerical index of the degree of relationship between two variables. The size of the correlation coefficient varies between zero and plus or minus one. Its size indicates the strength of the association between two variables. :: Slide 17 :: :: Slide 18 :: Naturalistic observation is when a researcher engages in careful observation of behavior without intervening directly with the subjects – allowing researchers to study behavior under conditions that are less artificial than experiments. It can be particularly useful for studying animals in their natural habitats. A case study is an in-depth and generally highly subjective or impressionistic report on a single individual that may be based on interviews, psychological testing, and so on.

4. :: Slide 19 :: :: Slide 20 :: Surveys use questionnaires or interviews to find out about specific aspects of people’s backgrounds, attitudes, or opinions. While descriptive and correlational methods extend the scope of psychological research, they do not permit scientists to manipulate variables, and therefore a cause and effect relationship cannot be proved. Clinical samples are often unrepresentative – drawing inferences about a population based on a sample only works if the sample is reasonably representative of the population. :: Slide 21 :: :: Slide 22 :: We already saw how an unrepresentative sample of the population can lead to inaccuracy – this is called the sampling bias. Another bias is the social desirability bias, which leads people to answer questions about themselves in a way that fits in with society’s expectations. Experimenters are fallible, and their research can be affected by a tendency to see what they want to see. This bias is called experimenter bias. Robert Rosenthal’s research on experimenter bias suggests that researchers may unintentionally influence the behavior of their subjects. One way to prevent experimenter bias is by conducting a double-blind study - one where neither the participants nor the researcher knows which is the control group and which is the experiment group. :: Slide 23 :: :: Slide 24 :: When individuals are given a medication or are in a treatment condition in an experiment, their expectations about the treatment may produce a placebo effect. Placebo effects are especially likely to occur when subjects expect that the treatment is linked to a change in behavior or reaction. For example, if someone drinks a virgin margarita and starts acting intoxicated, they are exhibiting signs of the placebo effect. The advantages of internet research include larger populations, reduced time and money, and a broader reach into sampling populations. A drawback of Internet-mediated research is that typically very few of the solicited subjects participate, which means that those who do might be an extreme group, indicating a sampling bias. In addition, internet studies lack aspects of control found in conventional studies, and participants may be distracted or intoxicated, for example.

5. :: Slide 25 :: :: Slide 26 :: Deception enables investigation of important issues and empirical evidence suggests that deception is not harmful to subjects. However, deception is inherently immoral and may undermine participants’ trust in others. Consider this question by Warwick: “If it is all right to use deceit to advance knowledge, then why not for reasons of national security, for maintaining the Presidency, or to save one’s own hide?” When, if ever, do you think deception is justified? Animals are used in research in situations where it is unethical to experiment on human participants. Such use of animals raises ethical issues about the nature of non-human animals and the rightful treatment of such animals. Neil Miller argued that, given the amount of abandoned and euthanized animals each year in the United Status, using animals to research advances in medical treatment is justified. :: Slide XX :: :: Slide XX :: Left blank Left blank :: Slide XX :: :: Slide XX :: Left blank Left blank