What are some flaws that can reduce the value of a study in psychology?

(1) People might not honestly answer a researcher’s questions; (2) the research process might alter people’s opinions instead of merely measuring them; (3) people might respond differently at different times; (4) people not included in a study might respond in a manner that differs from those who are included; (5) the psychologist’s phrasing of questions may affect a research participant’s answers; (6) some responses by a participant may be ambiguous; and (7) the researcher’s record of participants’ responses may be inaccurate.

Who is capable of thinking critically about problems in psychological research?

You are. You have the ability to detect flaws and apply the critical thinking skills you use in everyday life to fix them.

What are the three goals of scientific research?

In psychology, or any science, a researcher usually has one of three goals: description, prediction, and causal explanation.

What is the survey method?

In the survey method, psychologists learn about a large group of people by studying a subgroup of them. Researchers typically measure psychological qualities using this method, by asking questions, either in interviews or in survey items.

How do samples differ from populations? Why do researchers collect data from samples rather than from whole populations?

The overall group in whose opinions a researcher is interested is called the study’s population. The subgroup of the population to whom a survey is administered is called the study’s sample. Researchers don’t administer their surveys to all the people in the population because it is too big.

Why does random sampling increase the representativeness of a sample?

Random sampling minimizes the possibility that the sample differs from the population as a whole.

What is a correlational study?

A correlational study is a research design whose aim is to determine the relation between two measured variables.

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What scientific goal does a correlational study help psychologists to achieve?

Psychologists achieve the scientific goal of prediction through the use of correlational designs. The results of a correlational study indicate the degree to which one variable predicts another.

What is a scatterplot and how is it interpreted?

A scatterplot is a graph depicting the relation between two variables. The dots in the scatterplot indicate whether the two variables go together, that is, whether higher levels of one variable are associated with higher (or lower) levels of the other variable.

What is a positive correlation? A negative correlation?

A positive correlation is one in which a higher amount of one variable co-occurs with higher amounts of the other variable, whereas a negative correlation is one in which a lower amount of one variable co-occurs with higher amounts of the other variable.

What is a correlation coefficient? What are examples of strong and weak positive and negative correlation coefficients?

A correlation coefficient is a number that represents the strength of a correlation between any two variables. If the correlation is close to +1.0, then there is a very strong positive correlation. If it is close to −1.0, then there is a very strong negative correlation. If the correlation coefficient is close to 0, there is little or no correlation.

What is the major limitation of correlational designs?

The major limitation is that researchers cannot tell whether the relation between two variables is causal, coincidental, or based on a third variable that affects both.

What scientific goal is achieved through experimental designs?

Experimental designs enable psychologists to achieve the goal of causal explanation. By manipulating one variable and seeing whether the manipulation affects a second variable, the psychologist can determine whether the first variable is a cause of the second one.

How does an independent variable differ from a dependent variable?

In an experimental design, the independent variable is the manipulated variable, whereas the measured variable, or outcome, is the dependent variable.

What is a hypothesis?

In psychology, a hypothesis is a prediction about the result of a study.

What is a control group?

A control group is an experimental condition that does not receive the experimental treatment.

What are the two defining characteristics of an experiment?

An experiment is a form of research in which there is (1) more than one experimental condition and (2) the random assignment of research participants to experimental conditions.

How does random assignment enable researchers to establish a causal effect between independent and dependent variables?

Random assignment eliminates the effects of preexisting individual differences by evenly distributing them across conditions so the only thing that theoretically differs between the conditions is the independent variable(s).

What is measurement? What are three examples of measurement in psychology?

Measurement is any procedure in which numbers are assigned to objects or events. Three examples are: (1) counting the number of correct answers on a test; (2) creating numerical scales to represent a continuum of opinions; and (3) measuring the time it takes to solve a problem.

What is an operational definition?

An operational definition is the specification of a procedure that can be used to measure a variable.

In the measurement of variables, what are reliability and validity?

A measure possesses reliability if it consistently measures a psychological property. It possesses validity if it measures what it is supposed to measure—that is, if it is accurate.

What are some potential advantages and disadvantages of quantitative methods?

Numbers can describe events precisely; quantitative data yield concise summaries of research, and numbers are easier to compare to one another than are words and sentences. One potential disadvantage is that people might have thoughts and feelings not included in the measurement scale.

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What does it mean to say that a study’s outcomes are statistically significant?

The outcomes of research are called statistically significant if they vary from what would be expected by chance.

What are qualitative research methods? What are three examples of qualitative research strategies?

In qualitative research, researchers observe people’s statements and actions and describe their observations without using numberings. Three qualitative research strategies include clinical case studies, observational studies, and community-participation studies.

What are three advantages of qualitative data? What are some reasons most psychologists prefer quantitative to qualitative data?

Three advantages of qualitative data are that they are well suited to understanding (1) personal meaning and (2) the storylike quality of lives, and that they enable psychologists to (3) obtain evidence that is naturalistic. However, qualitative data do not provide the comparison, conciseness, and precision that quantitative data do, which is why so many psychologists prefer quantitative data.

What are three forms of psychological evidence that researchers obtain to study people’s thoughts, feelings, and behaviors?

(1) Self-report methods are a form of evidence in which participants provide information about themselves. (2) Observer-report methods ask people to report on someone else whom they know well. (3) Direct observation of behavior is a method of gathering evidence in which the researcher views the actions of research participants firsthand.

What are two limitations of self-reports as a source of evidence about people’s behavior?

In self-report studies, people may be (1) unwilling or even (2) unable to accurately report some information about themselves.

What are two main targets for research in studies of psychology and biology, and how do scientists learn about them?

Two main targets for research are psychologically relevant activity in the brain and the body. Two ways of studying the electrical activity in the brain are (1) electroencephalography (EEG), in which electrodes placed on the scalp record electrical activity, and (2) functional magnetic resonance imaging (fMRI), in which the brain’s blood flow is recorded while a person performs a mental task. Psychophysiological evidence provides information about the body. Psychophysiologists use tools such as skin conductance response to record levels of bodily arousal.

What is a scientific theory?

A scientific theory is a systematic, data-based explanation for a phenomenon or set of phenomena.

What is the relation between theory and evidence?

There is a back-and-forth, “two-way street” relation between theory and evidence. After scientists formulate a theory, scientific evidence is collected to determine whether the theory’s hypotheses can be confirmed. But before scientists formulate a theory, scientific evidence provides information about the world that guides theory development.

How are decisions about the ethics of a research proposal made?

In the United States, every major institution in which research is conducted has an Institutional Review Board (IRB), which assesses the ethics of proposed research by weighing the study’s benefits (the scientific knowledge gained) against its costs (the inconvenience and potential risk to participants).

What three principles guide ethical research in psychology?

First, research participation must be voluntary; participants cannot be made to feel coerced in any way. Second, potential participants must be informed—that is, they must be given all the information they would need to make a decision about whether or not to participate, in an informed consent form. Third, they have the right to withdraw at any time without penalty. In addition, researchers must provide participants with a debriefing: an explanation of the research at the conclusion of the study.