Key Terms

archival research

method of research using past records or data sets to answer various research questions, or to search for interesting patterns or relationships

attrition

reduction in number of research participants as some drop out of the study over time

cause-and-effect relationship

changes in one variable cause the changes in the other variable; can be determined only through an experimental research design

clinical or case study

observational research study focusing on one or a few people

confirmation bias

tendency to ignore evidence that disproves ideas or beliefs

confounding variable

unanticipated outside factor that affects both variables of interest, often giving the false impression that changes in one variable causes changes in the other variable, when, in actuality, the outside factor causes changes in both variables

control group

serves as a basis for comparison and controls for chance factors that might influence the results of the study—by holding such factors constant across groups so that the experimental manipulation is the only difference between groups

correlation

relationship between two or more variables; when two variables are correlated, one variable changes as the other does

correlation coefficient

number from -1 to +1, indicating the strength and direction of the relationship between variables, and usually represented by r

cross-sectional research

compares multiple segments of a population at a single time

debriefing

when an experiment involved deception, participants are told complete and truthful information about the experiment at its conclusion

deception

purposely misleading experiment participants in order to maintain the integrity of the experiment

deductive reasoning

results are predicted based on a general premise

dependent variable

variable that the researcher measures to see how much effect the independent variable had

double-blind study

experiment in which both the researchers and the participants are blind to group assignments

empirical

grounded in objective, tangible evidence that can be observed time and time again, regardless of who is observing

experimental group

group designed to answer the research question; experimental manipulation is the only difference between the experimental and control groups, so any differences between the two are due to experimental manipulation rather than chance

experimenter bias

researcher expectations skew the results of the study

fact

objective and verifiable observation, established using evidence collected through empirical research

falsifiable

able to be disproven by experimental results

generalize

inferring that the results for a sample apply to the larger population

hypothesis

(plural: hypotheses) tentative and testable statement about the relationship between two or more variables

illusory correlation

seeing relationships between two things when in reality no such relationship exists

independent variable

variable that is influenced or controlled by the experimenter; in a sound experimental study, the independent variable is the only important difference between the experimental and control group

inductive reasoning

conclusions are drawn from observations

informed consent

process of informing a research participant about what to expect during an experiment, any risks involved, and the implications of the research, and then obtaining the person’s consent to participate

Institutional Animal Care and Use Committee (IACUC)

committee of administrators, scientists, veterinarians, and community members that reviews proposals for research involving non-human animals

Institutional Review Board (IRB)

committee of administrators, scientists, and community members that reviews proposals for research involving human participants

inter-rater reliability

measure of agreement among observers on how they record and classify a particular event

longitudinal research

studies in which the same group of individuals is surveyed or measured repeatedly over an extended period of time

naturalistic observation

observation of behavior in its natural setting

negative correlation

two variables change in different directions, with one becoming larger as the other becomes smaller; a negative correlation is not the same thing as no correlation

observer bias

when observations may be skewed to align with observer expectations

operational definition

description of what actions and operations will be used to measure the dependent variables and manipulate the independent variables

opinion

personal judgments, conclusions, or attitudes that may or may not be accurate

participants

subjects of psychological research

peer-reviewed journal article

article read by several other scientists (usually anonymously) with expertise in the subject matter, who provide feedback regarding the quality of the manuscript before it is accepted for publication

placebo effect

people's expectations or beliefs influencing or determining their experience in a given situation

population

overall group of individuals that the researchers are interested in

positive correlation

two variables change in the same direction, both becoming either larger or smaller

random assignment

method of experimental group assignment in which all participants have an equal chance of being assigned to either group

random sample

subset of a larger population in which every member of the population has an equal chance of being selected

reliability

consistency and reproducibility of a given result

replicate

repeating an experiment using different samples to determine the research’s reliability

sample

subset of individuals selected from the larger population

single-blind study

experiment in which the researcher knows which participants are in the experimental group and which are in the control group

statistical analysis

determines how likely any difference between experimental groups is due to chance

survey

list of questions to be answered by research participants—given as paper-and-pencil questionnaires, administered electronically, or conducted verbally—allowing researchers to collect data from a large number of people

theory

well-developed set of ideas that propose an explanation for observed phenomena

validity

accuracy of a given result in measuring what it is designed to measure