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) a testable prediction about how the world will behave if an idea is correct, often worded as an if-then statement
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