CHPT 2 Psychological Research

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 manipulated to observe its effect on the dependent variable.

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.