AP Psychology: Science Practices

Cultural Norms

behavior patterns that are typical of specific groups

Confirmation Bias

the tendency to interpret new evidence as confirmation of one's existing beliefs or theories.

Hindsight Bias

"I knew it all along" phenomenon

Overconfidence

Tendency to overestimate our ability to make correct predictions

Independent Variables

Factors that are manipulated in an experiment

Dependent Variables

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

Confounding Variables

Factors that cause differences between the experimental group and the control group other than the independent variable

Random Assignment

Placing research participants into the conditions of an experiment in such a way that each participant has an equal chance of being allocated to any level of the independent variable.

Case Study

A method 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 relationship between two variables in which both variables either increase or decrease together

Negative Correlation

The relationship between two variables in which one variable increases as the other variable decreases

Meta-Analysis

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

Naturalistic Observation

A method 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 invalidated by experimental results.

Operational Definitions

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, to see whether the basic finding extends to other participants and circumstances

Central Tendency

A number that describes something about the "average" score of a distribution (ex: mean, median, mode)

Variation

A change or slight difference in condition, amount, or level.

Percentile Rank

Percentage of scores falling at or below a specific score.

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 value that occurs most frequently in a given data set.

Range

The difference between the highest and lowest scores in a distribution

Normal Curve

A symmetrical, bell-shape that describes the distribution of many types of data; most scores fall near the mean.

Positive Skew

High outlier

Negative Skew

Low outlier

Bimodal Distribution

A distribution with two modes

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 subset of a population being studied (sometimes, not always, representative)

Population

A group of organisms of the same species populating a given area

Representative Sample

A sample that accurately reflects the characteristics of the population as a whole

Random Sampling

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

Convenience / Opportunity Sample

Participants are selected who are available and willing to participate

Generalizing

Draw or state a general conclusion from a number or items or instances, making a statement about what several people or things have in common, finding and extending patterns.

Experimental Group

The people in an experiment that receives the variable being tested

Control Group

The people that do not receive the experimental treatment (may receive a placebo instead).

Placebo

A fake drug used in the testing of medication

Placebo Effect

Improvement or effect resulting from the mere expectation of improvement or effect

SIngle-Blind Study

A study in which the participants are unaware of whether they are in the control group or the experimental group.

Double-Blind Study

An experiment in which neither the participant nor the researcher knows whether the participant has received the treatment or the placebo.

Experimental Bias

Factors that distort how the independent variable affects the dependent variable in an experiment

Social Desirability Bias

The tendency for people to say what they believe is appropriate or acceptable (usually on a survey or questionnaire).

Qualitative Research Methods/Measures

Aim to understand the nature or meaning of experiences, which cannot be quantified into numbers

Structured Interviews

All applicants are asked the same set of standardized questions.

Quantitative Research Methods/Measures

Way of gathering data that can be quantified and then analyzing the data to draw conclusions.

Likert Scale

A way of formatting a survey questionnaire so that the respondent can choose an answer along a continuum

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 graphical depiction of the relationship between two variables

Correlation Coefficient

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

Effect Sizes

The most common way of quantifying and comparing outcomes across studies in meta-analytic reviews

Statistical Significance

How likely it is that an obtained result occurred by chance

Third Variable Problem

The concept that a correlation between two variables may stem from both being influenced by some third variable

Directionality

Possibility that when two variables, A and B, are correlated variable A causes variable B or variable B causes variable A.

Institutional Review

Process of examining studies for ethical concerns by a committee of peers

Informed Consent

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

Informed Assent

Participant's agreement to participate in the absence of full understanding

Protection from Harm

During a research study, participants should not experience negative physical or psychological effects, such as physical injury, lowered self-esteem, or embarrassment

Confidentiality

Respecting the privacy of all parties and keeping details secret

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