AP Psychology Unit 0: Science Practices

Cultural norms

prescriptions for how people should interact and what messages should mean in a particular setting

Confirmation bias

a tendency to search for information that supports our preconceptions and to ignore or distort contradictory evidence

Hindsight bias

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

Overconfidence

the tendency to be more confident than correct—to overestimate the accuracy of our beliefs and judgments.

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 influence a study's results

Dependent variable

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

Random assignment

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

Case study

a descriptive technique in which one individual or group is studied in depth in the hope of revealing universal principles

Correlation

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

Positive correlation

a correlation whereas one variable increases, the other also increases, or as one decreases so does the other. Both variables move in the same direction

Negative correlation

A correlation where as one variable increases, the other decreases

Meta-analysis

a procedure for statistically combining the results of many different research studies

Naturalistic observation

a descriptive technique of observing and recording behavior in naturally occurring situations without trying to manipulate and control the situation

Hypothesis

a testable prediction, often implied by a theory

Falsifiable

able to be disproven by experimental results

Operational definition

a carefully worded statement of the exact procedures used in a research study to accurately replicate another study

Replication

repeating the essence of a research study, usually with different participants in different situations, to see whether the basic finding extends to other participants and circumstances

Central tendency

a measure that represents the typical response or the behavior of a group as a whole

Variation

differences between results in a scientific study

Percentile rank

the percentage of scores below a specific score in a distribution of scores

Mean

the arithmetic average of a distribution, obtained by adding the scores and then dividing by the number of scores

Median

the middle score in a distribution; half the scores are above it and half are below it

Mode

the most frequently occurring score(s) in a distribution

Range

the difference between the highest and lowest scores in a distribution

Normal curve

the symmetrical bell-shaped curve that describes the distribution of many physical and psychological attributes. Most scores fall near the average, and fewer and fewer scores lie near the extremes.

Positive skew

A curve or distribution of scores that has extreme scores above the mean that are atypical of the majority of scores

Negative skew

A curve or distribution of scores that has extreme scores below the mean that are atypical of the majority of scores.

Bimodal distribution

a frequency distribution having two different values that are heavily populated with cases

Standard deviation

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

Regression toward the mean

the tendency for extremes of unusual scores to fall back (regress) toward their average

Sample

A relatively small proportion of people who are chosen in a survey so as to be representative of the whole.

Population

all those in a group being studied, from which samples may be drawn

Representative sample

randomly selected sample of subjects from a larger population of subjects

Random sampling

a sample that fairly represents a population because each member has an equal chance of being selected

Convenience sampling

using a sample of people who are readily available to participate

Generalizing

the ability to apply the findings of a particular research project to larger segments of society

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

Placebo

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

Placebo effect

the phenomenon in which the expectations of the participants in a study can influence their behavior

Single-blind study

study in which the subjects do not know if they are in the experimental or the control group

Double-blind study

study in which neither the experimenter nor the subjects know if the subjects are in the experimental or control group

Experimenter bias

a phenomenon that occurs when a researcher's expectations or preferences about the outcome of a study influence the results obtained

Social desirability bias

the tendency to respond to questions in a socially desirable manner

Qualitative research/methods

research in which the emphasis is placed on observing, describing, and interpreting people's behavior

Quantitative research/measures

research in which data is gathered from a large number of individuals and described using a statistical technique

Structured interviews

interviews in which all applicants are asked the same set of standardized questions, usually including situational, behavioral, background, and job-knowledge questions

Likert scales

ordinal-level scales containing seven points on an agree or disagree continuum

Representation of participants

how well the sample of participants in a study represents the larger population researchers are interested in

Peer review

a process by which the procedures and results of an experiment are evaluated by other scientists who are in the same field or who are conducting similar research

Scatterplot

A graphed cluster of dots, each of which represents the value of two variables. The slope of the points suggests the direction of the relationship between the two variables. The amount of scatter suggests the strength of the correlation

Correlation coefficient

a statistical index of the relationship between two things

Effect sizes

a measure of the strength of the relationship between two variables or the extent of an experimental effect

Statistical significance

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

Directionality problem (in correlation)

the situation in which it is known that two variables are related although it is not known which is the cause and which is the effect

Third variable problem (in correlation)

when a third variable causes a correlation between two other variables, making it seem like they have a causal relationship when they don't

Institutional review

a study is examined for ethical concerns by a committee knowledgeable about research and clinical practice

Informed consent

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

Informed assent

the agreement of someone not able to give legal consent to participate in the activity

Protection from harm

the right of research participants to be protected from physical or psychological harm

Confidentiality

the assurance that messages and information are available only to those who are authorized to view them

Deception

misleading participants about the true purpose of a study or the events that will actually transpire

Debriefing

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