Scientific Principles in Psychology

1		Doing scientific research involves using the scientific process. Once a researcher has observed a phenomenon or formulated an initial question about it, he or she forms a , or tentative explanation or prediction, about it. Researchers then test the idea, analyze the data, and determine if the hypothesis was correct or should be rejected. As additional evidence comes in, researchers attempt to build , which are sets of formal statements that explain how and why events are related. There are two main approaches to understanding behavior. After-the-fact understanding used to explain a behavior is known as . Scientists, though, typically try to understand a phenomenon through , , and . Psychologists study , which are characteristics that vary. Defining a variable in terms of the specific procedures used to measure or produce it is known as an . Psychologists measure behavior in a number of different ways. - ask people to report on their own knowledge, beliefs or feelings. Measures of heart rate, blood pressure etc. are known as . Already existing records of people’s behavior that are used for research are known as .

Methods of Research

2		An in-depth analysis of an individual, group, or event is called a . Sometimes researchers are interested in describing behavior that occurs in its natural setting, a type of research called . Information about a topic is obtained by administering questionnaires or interviews to many people in . In survey research, researchers are interested in making conclusions about a , which represents the entire set of individuals about whom we are interested in making conclusions. Because it is often impractical to study an entire population, researchers typically study a subset of that population called a . To draw valid conclusions about the population, the sample must accurately reflect the characteristics of the population. Such a sample is known as a . When every member of the population has an equal probability of being chosen for the sample, the researcher has created a . When researchers are interested in measuring the associations between events, they conduct , though such research does not indicate causation. A statistic that measures the direction and strength of the relationship between two variables is called a . When higher scores on one variable are associated with lower scores on a second variable, the researcher has discovered a correlation. When higher scores on one variable are associated with higher scores on a second variable, the researcher has discovered a correlation. A type of research method that is used to determine cause-and-effect relationships is known as an . In an experiment, the variable that is manipulated by the experimenter is known as the variable, whereas the variable that is measured by the experimenter is known as the variable. Through , participants in an experiment are often assigned to groups. The group is the group that receives a treatment, while the group does not.

Threats to the Validity of Research

3		It is important for researchers to establish that their research is valid. represents the degree to which an experiment supports clear causal conclusions. A problem with internal validity exists when two variables are intertwined in such a way that we cannot determine which one has influenced a dependent variable, a condition known as . Cues that participants pick up about the hypothesis of a study are known as . Inactive or inert substances known as are often used to control for participant expectancy effects. When an experimenter subtly and unintentionally influences the behavior of participants so that it is consistent with the hypothesis of the study, the effects are called effects. Researchers are interested in establishing not only internal validity but also in establishing , which is the degree to which the results of a study can be generalized to other people, settings, and conditions. To determine whether a tentative conclusion reached in one study is valid, the results of the study must be . Research designed to statistically combine the results of many studies involves a statistical procedure known as - .

Ethical Principles in Human and Animal Research

4		When research participants are given a full description of the research, are informed of risks, and are told that they are free to withdraw from the study without penalty, the participants have received . Studies in which participants are misled as to the nature of the study are known as studies.