Psych Vocab Unit 0 Research Methods

critical thinking

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

control group

the group in an experiment that does not receive the treatment, providing a baseline for comparison to determine whether the independent variable caused a change in the dependent variable

case study

in-depth examination of an individual, group, or phenomenon to gain detailed insights into behavior and mental processes

correlation

a statistical measure that describes the strength and direction of a relationship between two variables, without implying causation

correlation coefficient

a numerical value from -1 to +1 that indicates the strength and direction of a linear relationship between two variables, but it does not imply causation

culture

the shared values, beliefs, language, rituals, traditions, and other behaviors passed from one generation to the next within a social group, including the characteristic attitudes and behaviors of a particular group in society

confounding variable

an unexpected factor that interferes with the relationship between the independent and dependent variables, potentially leading to misleading conclusions

double-blind procedure

a research method in which neither the participants nor the experimenters know who is receiving a particular treatment, designed to minimize bias and ensure objective results

debriefing

a structured post‑event process used either to explain a research study to participants or to help people process a stressful or traumatic experience

dependent variable

the outcome or response that researchers measure to see how it changes in relation to an independent variable

experiment

a controlled study in which researchers manipulate an independent variable, measure a dependent variable, and control extraneous factors to determine causal relationships

experimental group

a set of participants in a study who are exposed to a specific treatment or manipulation of the independent variable to test its effects

falsifiable

hypothesis or theory that can be empirically tested and potentially proven false through observation or experimentation

hypothesis

a specific, testable prediction about the relationship between variables, formulated before data collection to guide research

hindsight bias

the psychological tendency to perceive past events as more predictable than they actually were, often summarized as the “I‑knew‑it‑all‑along” effect

illusory correlation

the perception of a relationship between two variables—such as people, events, or behaviors—when no actual relationship exists; overstimulating strength of relationship

independent variable

the factor a researcher deliberately manipulates or controls to examine its effect on a dependent variable

null hypothesis

a statement predicting that there is no meaningful effect, difference, or relationship between variables, and that any observed variation is due to chance

protection from harm

the ethical duty to prevent or minimize any physical, psychological, social, economic, or legal harm to research participants or clients, ensuring they leave in the same—or better—state than when they began

descriptive statistics

techniques used to organize, summarize, and display data from a sample—typically through measures like the mean, median, mode, range, and standard deviation

inferential statistics

statistical techniques that allow researchers to draw conclusions about a population based on data collected from a sample, using probability to estimate error and test hypotheses

informed consent

the process by which individuals are given full, understandable information about a study or treatment and voluntarily agree to participate, free from coercion

meta analysis

a statistical method that combines results from multiple studies to produce a single, more precise estimate of an effect

mode

refers to the most frequently occurring score or value in a dataset, making it a key measure of central tendency used especially with categorical or nominal data

mean

arithmetic average of a set of scores—calculated by adding all values and dividing by the number of values—and is the most commonly used measure of central tendency in psychological research

naturalistic observation

research method in which behavior is observed and recorded in real‑world settings without manipulating variables or interfering with the environment

normal bell shape curve

symmetric probability distribution where most scores cluster around the mean, with fewer scores appearing toward the extremes; the mean, median, and mode are identical at the center, and fixed proportions of scores fall within each standard‑deviation range

operational definition

precise, measurable description of how a researcher will observe or quantify an abstract concept

population

the subfield of psychology that studies the behavior, attitudes, and mental processes of human populations, focusing on patterns and trends across groups rather than individuals

placebo effect

clinically significant change in symptoms or behavior produced by an inert treatment, driven primarily by a person’s expectations or beliefs rather than any active therapeutic ingredient

percentile rank

the percentage of scores in a distribution that fall at or below a given score, indicating an individual’s relative standing among a norm group

peer reviewer

qualified professionals who evaluate the quality, validity, and ethical standards of research or academic work before it is published

range

the simplest measure of variability: the difference between the highest and lowest values in a dataset (Range = maximum − minimum)

quantitative research

involves measuring psychological variables numerically and analyzing them with statistical methods to test hypotheses, identify patterns, and predict behavior

qualitative research

method of inquiry that produces descriptive, non-numerical data to understand human experiences, behaviors, and social contexts from the perspective of participants

random assignment

the process of placing participants into experimental or control groups entirely by chance, ensuring each person has an equal likelihood of being assigned to any condition

regression towards the mean

the statistical tendency for an extreme score or measurement to be followed by one that is closer to the average, due to imperfect measurement reliability and random error

confirmation bias

the tendency to search for, interpret, and remember information in ways that support one’s existing beliefs, while giving less attention to contradictory evidence

deception

the intentional distortion or withholding of facts to mislead others, involving acts such as lying, omission, exaggeration, or strategic silence, with the core element being the intent to create a false belief

variance

a statistical measure of how much individual scores differ from the mean, reflecting the spread or dispersion of data within a sample or population

reliability

the consistency or repeatability of a measurement—whether a test or instrument yields the same results under the same conditions; reflects how stable and dependable scores are across time, raters, or test items, and is essential for trustworthy research and diagnosis

replication

process of repeating a study—either closely or with variations—to verify whether its original findings hold up, strengthen confidence in results, and assess their reliability across different contexts

random sample

a subset of a population selected so that every individual has an equal and independent chance of being chosen, ensuring the sample represents the larger population

sampling bias

a systematic error in selecting participants such that some groups in the target population are over‑ or under‑represented, producing a sample that does not accurately reflect the population and threatening external validity

self report bias

a systematic error in research that occurs when individuals inaccurately report their own thoughts, feelings, or behaviors, often due to social desirability or memory limitations

social desirability bias

a response bias in which people answer questions in ways they believe will be viewed favorably by others, often over‑reporting “good” behavior and under‑reporting “bad” behavior

skewed distribution

a data pattern where scores cluster heavily on one side of the scale and extend into a long tail on the other, indicating asymmetry in the variable being measured

scatterplot

a graphical representation that displays the relationship between two continuous variables, with each dot representing a single observation or participant

survey

a research method used to systematically collect information about people’s thoughts, feelings, behaviors, or experiences through structured questions

statistical significance

a study’s results are unlikely to be due to chance, typically determined by whether the p‑value falls below a preset threshold such as 0.05; threshold indicates how probable the observed data would be if the null hypothesis were true

standard deviation

a statistical measure that shows how much individual scores typically differ from the mean, indicating whether responses are tightly clustered or widely spread

theory

an organized set of principles that explains and predicts patterns in human thought and behavior, built from empirical evidence rather than guesswork

validity

refers to how accurately a test, measure, or study assesses what it claims to measure, ensuring conclusions are truthful, accurate, and supported by evidence

likert scale

a structured rating tool where people indicate their level of agreement or disagreement with statements—typically on a 5‑ or 7‑point scale such as “strongly disagree” to “strongly agree.” It was developed by Rensis Likert and is widely used to measure attitudes, opinions, and feelings

non-experimental design

a research approach in which the investigator does not manipulate an independent variable or randomly assign participants to conditions, instead measuring variables as they naturally occur

median

the middle value in a dataset that divides it into two equal halves, providing a robust measure of central tendency in psychological research

longitudinal study

an observational research design in which the same individuals are repeatedly measured over extended periods—ranging from weeks to decades—to track changes in behaviors, thoughts, emotions, or development over time

confidentiality

the ethical and legal duty of mental‑health professionals to keep all client information private, except in specific situations such as imminent danger, abuse reporting, or court orders

framing

presenting the same information in different ways to influence how people perceive, evaluate, and decide, often shaping choices more through wording than content