AP Psychology Unit 0: Approaches, Research, and Statistics

Psychological approaches

Different perspectives used to explain the same behavior.

Evolutionary approach

Explains behavior as an adaptation developed through natural selection.

Biological approach

Explains behavior through physical processes such as genes and brain structures.

Humanistic approach

Emphasizes free will, personal growth, and self-concept.

Sociocultural approach

Examines how behavior is influenced by culture and social groups.

Behavioral approach

Explains observable behavior as learned through conditioning.

Cognitive approach

Examines how thoughts and beliefs affect behavior.

Psychodynamic approach

Explains behavior through unconscious conflicts and early experiences.

Hindsight Bias

Believing after an event that you predicted it beforehand.

Overconfidence

Overestimating the accuracy of your knowledge or predictions.

Barnum or Forer Effect

Accepting a vague personality description as specifically describing you.

Critical Thinking

Carefully examining evidence, assumptions, and possible biases.

Theory

A broad explanation that organizes observations and predicts behavior.

Hypothesis

A specific and testable prediction based on a theory.

Operational Definition

An exact explanation of how a variable is measured or manipulated.

Replication

Repeating a study to determine whether similar results occur.

Descriptive Method

Observes and describes behavior without manipulating variables.

Correlational Method

Measures relationships between variables without establishing causation.

Experimental Method

Tests cause and effect by manipulating variables.

Case Study

An in-depth examination of one person or unusual situation.

Naturalistic Observation

Observing behavior in a natural environment without manipulation.

Survey

Collecting self-reported information through questions or interviews.

Cross-Sectional Research

Different groups are compared at one point in time.

Longitudinal Research

The same participants are studied repeatedly over time.

Population

The entire group researchers want to understand.

Sample

The smaller group that actually participates in the study.

Random Sample

A sample selected so every member of the population has an equal chance of being chosen.

Sampling Bias

The sample does not accurately represent the population.

Correlation

Measures the relationship between two variables.

Scatterplot

A graph where each dot represents the values of two variables.

Correlation Coefficient

Represents the strength and direction of a correlation.

Positive Correlation

The variables move in the same direction.

Negative Correlation

One variable increases as the other decreases.

Illusory Correlation

Believing two variables are related when they are not.

Experiment

Does additional sleep improve test scores?

Independent Variable

The variable manipulated by the researcher.

Dependent Variable

The outcome measured by the researcher.

Confounding Variable

An uncontrolled factor that changes with the independent variable and could explain the result.

Experimental Group

Receives the treatment being tested.

Control Group

Does not receive the active treatment or receives a placebo or standard condition.

Random Assignment

Participants are placed into conditions by chance.

Random Sampling

Determines who participates; improves generalizability.

Between-Subjects Design

Different participants experience different conditions.

Within-Subjects Design

The same participants experience every condition.

Placebo

An inactive treatment made to resemble the real treatment.

Placebo Effect

A change caused by expectations rather than the active treatment.

Single-Blind Study

Participants do not know which condition they are in.

Double-Blind Study

Neither the participants nor the researchers interacting with them know who received the real treatment.

Observer Error

Researcher expectations or inconsistent observations affect results.

Participant Error

Participants lie, guess the hypothesis, react to expectations, or give socially acceptable answers.

Administrative Error

Mistakes occur in instructions, testing conditions, equipment, scoring, or data entry.

Reliability

Reliability means consistency.

Validity

Validity means whether a measure accurately does what it claims.

Mean

Add the scores and divide by the number of scores.

Median

Middle score after arranging the data.

Mode

Most frequent score.

Range

Highest score minus lowest score.

Standard Deviation

Measures the typical distance of scores from the mean.

Normal Distribution

A symmetrical bell-shaped distribution.

P-Value

Shows how surprising the results would be if the null hypothesis were true.

Null Hypothesis

The assumption that no real effect or relationship exists.

Causation

One variable produces change in another.

Cross-sectional

Different people once.

Longitudinal

Same people over time.