AP Psychology Unit 2: Research Methods Key Terms

Hidsight bias

the tendency to believe, after learning and outcome, that one would have foreseen it.

Critical thinking

thinking that does not blindly accept arguments and conclusions, but examines assumptions, discerns hidden values, evaluates evidence, and assesses conclusions.

Theory

an explanation using an integrated set of principles that organizes observations and predicts behaviors or events.

Hypothesis

a testable prediction, often implied by a theory.

Operational definition

a statement of the procedures used to define research variables.

Replication

repeating the essence of a research study, usually with different participants in different situations

Case study

an observation technique in which one person is studied in depth in the hope of revealing universal principles.

Survey

a technique for ascertaining self reported attitudes or behaviors, usually by questioning a representative, random sample of a group.

Population

all the cases in a group being studied, from which samples may be drawn.

Random sample

a sample that fairly represents a population because each member has an equal chance of inclusion.

Naturalistic observation

observing and recording behavior in naturally occurring situations without trying to manipulate or control the situation.

Correlation

a measure of the extent to which two factors vary together, and thus of how well either factor predicts the other.

Correlation coefficient

a statistical index of between two things (from -1 to +1).

Scatterplot

a graphed cluster of dots, each of which represents the values of two variables.

Illusory correlation

the perception of a relationship where none exists.

Experiment

a research method in which an investigator manipulates one or more factors to observe the effect on some behavior or mental process.

Random assignment

assigning participants to experimental and control groups by chance, thus minimizing preexisting differences between those assigned to the different groups.

Double-blind procedure

an experimental procedure in which both the research participants and the research staff are ignorant about whether the research participants have received the treatment or a placebo.

Placebo effect

experimental results caused by expectations alone; any effect on behavior caused by the administration of an inert substance or condition, which the recipient assumes is an active agent.

Experimental group

in an experiment, the group that is exposed to the treatment, that is, to one version of the independent variable.

Control group

in an experiment, the group that is not exposed to the treatment; contrasts with the experimental group and serves as a comparison for evaluating the effect of the treatment.

Independent variable

the experimental factor that is manipulated; the variable whose effect is being studied.

Confounding variable

a factor other than the independent variable that might produce and effect in an experiment.

Dependent Variable

the outcome factor; the variable that may change in response to manipulations of the independent variable.

Mode

the most frequently occurring score(s) in a distribution.

Mean

the arithmetic average of a distribution.

Median

the middle score in a distribution

Range

the difference between the highest and lowest scores in a distribution.

Standard deviation

a computed measure of how much score vary around the mean score.

Normal curve

a symmetrical bell-shaped curve that describes the distribution of many types of data

Statistical significance

a statistical statement of how likely it is that an obtained result occurred by chance.

Culture

the enduring behaviors, ideas, attitudes, and traditions shared by a group of people and transmitted from one generation to the next.

Informed consent

an ethical principle that research participants be told enough to enable them to choose whether they wish to participate.

Debriefing

the post-experimental explanation of a study including its purpose and any deceptions to its participants