Chapter 2: Research Methods

Experience

Personal events relating to a phenomenon

Intuition

Subjective feelings about what makes sense

Scientific method

The process of basing one’s confidence in an idea on systematic, direct observations of the world, usually by setting up research studies to test ideas

Theory-data-cycle

The process of the scientific method, in which scientists collect data that can either confirm or disconfirm a theory

Theory

A set of propositions explaining how and why people act, think, or feel

Hypothesis

A specific prediction stating what will happen in a study if the theory is correct

Data

A set of empirical observations that scientists have gathered

Replication

When a study is conducted more than once on a new sample of participants, and obtains the same basic results

Journal

A periodical containing peer-reviewed articles on a specific academic discipline, written for a scholarly audience

Variable

 Something of interest that varies from person to person, or situation to situation

Measured variables

A variable whose values are simply recorded

Manipulated variable

A variable whose values the researcher controls, usually by assigning different participants to different levels of that variable

Operationalizing a variable

turning it into a number, which can be recorded and analyzed

Self-reporting

 People describe themselves in an interview or survey, using a rating scale

Direct observation

Researchers observe and record the occurrence of behavior

Descriptive research

A type of study in which researchers measure one variable at a time

Sample

The group that participated in the research, and who belong to the larger group (the population of interest) that the researcher is interested in understanding

Population of interest

The full set of cases the researcher is interested in

Random sampling

A way of choosing a sample of participants for a study in which participants are selected without bias

Observational research

A descriptive research method in which psychologists measure their variable of interest by observing and recording what people are doing

Naturalistic observation

An observational research method in which psychologists observe the behavior of animals and people in their normal, everyday worlds and environments

Case study

An observational research method in which researchers study one or two individuals in depth, often those who have a unique condition

Correlational research

 A type of study that measures two (or more) variables in the same sample of people, and then observes the relationship between them

Scatterplot

A figure used to represent a correlation

Correlation is not causation

1. Two variables must be correlated

2. One variable must precede the other

3. There must be no reasonable alternative explanations for the pattern of correlation

Third-variable problem

 For a given observed relationship between two variables, an additional variable that is associated with both of them, making the additional variable an alternative explanation for the observed relationship

Experimental research

A study in which one variable is manipulated, and the other is measured, can provide evidence that one variable causes another

Independent variable

The manipulated variable in an experiment

Dependent variable

The measured variable in an experiment

Random assignment

A procedure used in experimental research in which a random method is used to decide which participants will receive each level of the independent variable

Experimental (treatment) group

 In an experiment, a group or condition in which some proposed cause is present

Control (comparison) group

In an experiment, a group or condition in which some proposed cause is not present

Placebo condition

In an experiment, a group or condition in which people expect to receive a treatment but are exposed to only an inert version, such as a sugar pill

Random sampling

A way of choosing a sample of participants for a study without bias, which allows findings to be generalized from the sample to the larger population of interest

Validity

The appropriateness or accuracy of a conclusion or decision

Construct validity

The specific assessment of how accurately the operationalizations used in the study capture the variables of interest

Reliability

the degree to which a measure yields consistent results each time it is administered.

External validity

The degree to which it is reasonable to generalize from a study’s sample to its population of interest

Internal validity

The ability of a study to rule out alternative explanations for a relationship between two variables; one of the criteria for supporting a causal claim

Confound

An alternative explanation for a relationship between two variables; specifically, in an experiment, when two experimental groups accidentally differ on more than just the independent variable, which causes a problem for internal validity

Descriptive statistics

A graph or computation that describes the characteristics of a batch of scores, such as its distribution, central tendency, or variability

Frequency distribution

A descriptive statistic that takes the form of a bar graph in which the possible scores on a variable are listed on the x-axis and the total number of people who had each score is plotted on the Y-axis

Mean

A measure of central tendency that is the arithmetic average of a group of scores

Median

A measure of central tendency that is the middlemost score; it is obtained by lining up the scores from smallest to largest and identifying the middle score

Mode

A measure of central tendency that is the most common score in a batch of scores

Variability

The extent to which scores in a batch differ from each other

Range

The difference between the highest and lowest scores in a batch

Standard deviation

A variability statistic that calculates how much, on average, a batch of scores varies around its mean

Effect size

A numerical estimate of the strength of the relationship between two variables. It can take the form of a correlation coefficient or, for an experiment, the difference between two group means divided by the standard deviations of the two groups

Inferential statistics

A set of procedures used to estimate whether a pattern of results represents a true relationship or difference in the population

Statistical significance

A process of inference that applies rules of logic and probability to estimate whether the results obtained in a study’s sample are the same in a larger population

Meta-analysis

A process in which researchers locate all of the studies that have tested the same variables and mathematically average them to estimate the effect size of the entire body of studies

Institutional Review Board (IRB)

A local panel of researchers, teachers, citizens, and others who determine whether a research study lives up to the community’s ethical standards

The ethical principle of autonomy

Each research participant has the right, without intimidation or coercion, to decide whether to participate

Informed consent

An application of the ethical principle of autonomy, in which a researcher explains the procedures of a study, including its risks and potential benefits, to the potential participants, who then decide whether to take part (Tuskegee Syphilis Study)

The ethical principle of beneficence

The benefits of the study must outweigh the risks of harm

The ethical principle of justice

 Participants bearing the burden of research must be representative of the population who will benefit from the research

Replacement

Find an alternative for animals when possible

Refinement

Modify procedures to minimize animal distress

Reduction

Use the fewest animal subjects possible