the sciences

psychology

the scientific study of behavior and mental processes

cognition

The process of receiving, processing, storing, and using information.

confirmation bias

the cognitive tendency to search for, interpret, favor, and recall information that confirms one's pre-existing beliefs while ignoring or devaluing contradictory evidence

independent variable

the experimental factor or "cause" that the researcher manipulates or changes to determine its effect on another variable

case study

a descriptive research method involving an in-depth, longitudinal analysis of a single individual, small group, or unique phenomenon

hypothesis

a testable, falsifiable prediction or educated guess about the relationship between two or more variables, usually derived from a theory

confounding variable

an unwanted, uncontrolled extraneous variable that influences both the independent and dependent variables

convenience sampling

a non-probability sampling method where researchers select participants based on ease of access, proximity, and availability, rather than random selection

experimental group

the subset of research participants who are exposed to the independent variable—the specific treatment, manipulation, or condition being tested

single-blind procedure

an experimental design where participants are unaware of which group they are assigned to (experimental or control), but the researcher conducting the study is aware

qualitative research

a non-numerical, exploratory research method focused on understanding human behavior, experiences, and emotions through detailed descriptions

correlational study

a non-experimental research method that measures the statistical relationship or association between two or more variables without manipulating them

Institutional Review Board (IRB)

an administrative committee at research institutions that reviews and approves research proposals involving humans or animals to ensure studies are ethical, safe, and comply with federal regulations

deception

an ethical guideline violation if misused, referring to the act of deliberately misleading or lying to research participants about the true purpose, nature, or procedures of a study

variation

the diversity of traits within a population (biological/behavioral differences) or the spread of data points in statistics (dispersion)

mode

the measure of central tendency representing the most frequently occurring score or value in a data set

bimodal distribution

a data set or frequency histogram featuring two distinct peaks (modes) rather than one

correlation coefficient

A correlation coefficient (often denoted as 𝑟) is a statistical measure ranging from −1.00 to +1.00 that quantifies the direction and strength of the relationship between two variables.

behavior perspective

focuses on how observable behaviors are learned, maintained, or changed through environmental interaction, conditioning, and reinforcement rather than internal mental processes

evolutionary perspective

a theoretical approach that explains human behavior, emotions, and cognitive processes as adaptations shaped by natural selection to enhance survival and reproductive success

hindsight bias

the "I-knew-it-all-along" phenomenon, where people believe, after learning an outcome, that they would have foreseen or predicted it

dependent variable

the factor measured by the researcher to determine the effect of the independent variable (IV). It is the outcome or response that "depends" on the manipulations made to the independent variable.

correlational study

a non-experimental research method that measures the statistical relationship or association between two or more variables without manipulating them

falsifiable

the capacity for a hypothesis, theory, or belief to be proven wrong through empirical observation, research, or experimentation

sample

a smaller, manageable subset of individuals selected from a larger population to participate in a research study

random sample

a subset of individuals chosen from a larger population where every member has an equal chance of being selected

control group

the subset of research participants in an experiment who do not receive the experimental treatment or independent variable

double-blind procedure

an experimental procedure where both participants and research staff are ignorant (blind) about who has received the treatment or a placebo

structure interview

a standardized, quantitative research method in AP Psychology where an interviewer asks a pre-set list of questions in a fixed order, often using closed-ended, yes/no, or multiple-choice formats

self report bias

the tendency for research participants to provide inaccurate, distorted, or dishonest information about themselves, their thoughts, or their behaviors

ethics

the guidelines and moral principles—such as beneficence, integrity, and respect—that govern research and therapeutic practices to ensure participant safety, confidentiality, and welfare. Developed by organizations like the APA, these standards prevent harm, ensure fairness, and uphold professional integrity.

confederates

individuals working for the researcher who pose as fellow participants

percentile rank

a descriptive statistic representing the percentage of scores in a distribution that fall at or below a particular score

range

the numerical difference between the highest and lowest scores in a dataset

standard deviation

a measure of variability indicating the average distance between scores and their mean

statistical significance

indicates that research results (differences between groups) are likely "real" and not caused by chance

psychodynamic perspective

how unconscious drives, conflicts, and early childhood experiences shape personality and behavior

sociocultural perspective

examines how social situations, cultural norms, and environments influence an individual’s behavior, thoughts, and feelings

overconfidence

a cognitive bias where a person's subjective confidence in their judgments is reliably higher than the objective accuracy of those judgments

random assignment

an experimental technique where participants are placed into either the experimental or control group purely by chance, giving everyone an equal likelihood of assignment to any condition

meta-analysis

a statistical technique used in AP Psychology to combine and analyze data from multiple independent studies on a specific topic

experimenter bias

the unconscious, unintentional tendency of researchers to influence the results of an experiment to confirm their own expectations or hypothesis

quantitative research

a method focusing on gathering, measuring, and analyzing numerical data to identify patterns, test hypotheses, and determine cause-and-effect relationships

directionality problem

a limitation of correlational research where it is impossible to determine which variable causes the other, even if a relationship exists

informed consent

an ethical guideline requiring researchers to obtain voluntary, knowledgeable permission from participants before a study

debrief

an essential ethical procedure where researchers provide participants with a full explanation of a study's true purpose, procedures, and any deception used, immediately after their participation

mean

the arithmetic average of a dataset, calculated by summing all individual scores and dividing by the total number of scores

normal/bell curve

a symmetrical, bell-shaped frequency distribution where most scores cluster around the mean, with fewer scores at the extremes

percentile rank

the percentage of scores in a distribution that fall at or below a specific score

biological perspective

examines how physiological processes—genetics, neurotransmitters, hormones, and brain structures—shape human behavior and mental processes

experiment

a research method used to determine cause-and-effect relationships by manipulating one or more independent variables (IV) to measure their effect on dependent variables (DV) while controlling for extraneous factors

non-experimental methods

methods that study behavior without manipulating an independent variable (IV) or randomly assigning participants to groups

naturalistic observation

a descriptive research method where researchers observe and record behavior in its natural setting without manipulating or controlling the environment

replication

the process of repeating a research study—usually with different participants in different situations—to determine if the original findings are reliable, consistent, and can be generalized to other people or circumstances

representative sample

a small subset of a target population that accurately mirrors the key characteristics—such as age, gender, socioeconomic status, and diversity—of the larger group

generalizability

the extent to which research findings from a specific sample can be applied to the larger population or different contexts

placebo

any effect on behavior or physical health caused by an inert substance or condition (a "placebo"), rather than the actual, active treatment.

social desirability bias

the tendency of survey respondents and experimental participants to answer questions in a manner that will be viewed favorably by others

Likert scale

a psychometric tool used in AP Psychology to measure attitudes, opinions, or perceptions by asking respondents to rate their level of agreement on a fixed scale

peer review

the critical, independent evaluation of psychological research by other experts in the same field before it is published in a professional journal

confidentiality

an ethical guideline requiring psychologists and researchers to protect participant/client privacy by keeping personal data and test results anonymous and secure, only disclosing information with consent or legal authorization

central tendency

a descriptive statistic that identifies the single, central score that best represents an entire set of data

median

the middle score in a distribution, arranged from lowest to highest, dividing the data set exactly in half

skewed curve

an asymmetrical frequency distribution where data points cluster on one side, resulting in a long tail, indicating that the mean, median, and mode are not equal

regression towards the mean

the statistical tendency for extreme scores or behaviors to move closer to the average (mean) upon a second measurement

effect size

a quantitative, standardized measure indicating the magnitude or strength of a relationship between two variables or the difference between group means, focusing on practical significance rather than just statistical significance