AP Psychology 2025 Vocab

Hypothesis

A tentative explanation - must be FALSIFIABLE (able to be supported or rejected)

Operational Definition

A clear, precise, quantifiable definition of your variables - allows REPLICATION and collection of RELIABLE data

Qualitative data

Descriptive data (ex. eye color)

Quantative data

Numerical data - IDEAL and necessary for statistics

Population

Everyone the research could apply to

Sample

The people (or person) specifically chosen for your study

Correlation

Identifies relationship between two variables

Directionality Problem

Which direction does the correlation go? (ex. depression cause low self-esteem, low self-esteem causes depression, or a 3rd variable?)

3rd Variable Problem

Different variable is responsible for relationship (ex. ice cream and murder)

Positive Correlation

Variables increase and decrease together

Negative Correlation

As one variable increases, the other decreases

Experiment

Purposefully manipulate variables to determine cause/effect

Independent Variable

Purposefully altered by researcher to look for effect

Experimental Group

Received the treatment (part of the independent var.) can have multiple groups

Control Group

Placebo, baseline (part of the independent var.) can only be 1

Dependent Variable

Measured variable (is DEPENDENT on the independent variable)

Placebo Effect

Any observed effect on a behavior that is "caused" by the placebo (shows effectiveness of experimental treatment), usually fixed with blinded studies

Single-blind study

Only participant blind (doesn't know whether they are in the experimental or control group), used if the experimenter can't be blind (gender, age, etc.)

Double-blind study

An experiment in which neither the participant nor the experimenter are aware of which condition people are assigned to (ex. drug studies)

Confound

Error/flaw in study that is accidentally introduced (can be called a confounding variable)

Random Assignment

Assigns participants to either control or experimental group at random - minimizes bias, increase chance of equal representation - allows you to say cause/effect

Naturalistic observation

Observing people in their natural settings - real world validity, but no cause/effect

Case Study

Studies (usually) ONE person in great detail - collect lots of info but not cause/effect

Meta-analysis

Combines multiple studies to increase sample size and examine effect sizes

Descriptive statistics

Show shape of the data

Measures of Central Tendency

Mean, median, mode

Mean

Average - most effective when used in normal distribution

Median

Middle number - most effective when used in skewed distribution

Mode

Number that occurs most often

Bimodal

Has two modes (two peaks on graph) - usually indicates good and bad scores

Skews

Created by outliers

Negative skew

Mean is to the left (negative side), mode is to the right - low outlier

Positive skew

Mean is to the right (positive side), mode is to the left - high outlier

Measures of Variation

Range, Standard deviation

Range

Distance between smallest and biggest number

Standard deviation

Average amount the scores are spread from the mean (bigger SD = more spread)

Inferential Statistics

Establishes significance (meaningfulness)

Statistical significance

Results not due to chance, experimental manipulation caused the different in means

Effect size

Data has practical significance (bigger = better)

Confidentiality

Ethical guideline - names/info kept secret

Informed Consent

Ethical guideline - must agree to be part of study

Informed Assent

Ethical guideline - minors AND their parents must agree to be part of a study

Debriefing

Ethical guideline - must be told the true purpose of the study (done after deception)

Deception

Ethical guideline - must be warrented

No harm

Ethical guideline - no harm will be done to the patient, physical or mental

Surveys

Usually turned into correlation, subject to self-report bias

Social desirability bias

Lying to look good

Wording effects

How you frame the question can impact your answers

Random Sample

Selection method for choosing participants for your study - everyone has a chance to take part, increases GENERALIZABILITY

Representative sample

Sample mimics the general population (ethnic, gender, age)

Convienience Sample

Select participants based on availability - less representative and less generalizability

Sampling bias

Sample isn't representative, due to convenience sampling

Cultural norms

Behaviors of a particular group can influence research results

Experimenter/participant bias

Experimenter/Participant expectations can influence outcome

Cognitive Bias

Bias in thinking/judgment

Confirmation bias

Finding info that supports our preexisting beliefs

Hindsight bias

"I knew it all along"

Overconfidence

Overestimate our knowledge/abilities

Hawthorne effect

People change behavior when watched

Evolutionary psychology

Study how natural selection influences behavior

Heredity (nature)

How genes influence your behavior

Environment (nurture)

How outside situations influence your behavior

Central NS

Brain and spinal cord

Peripheral NS

Rest of the NS (somatic, autonomic, sympathetic, parasympathetic) - relays to the central NS

Somatic NS

Voluntary movement, has sensory and motor neurons

Autonomic NS

Involuntary organs (heart, lungs, etc) contains the sympathetic and parasympathetic NS

Sympathetic NS

Fight/flight response (generally activates functions - exception is digestion)

Parasympathetic NS

Rest and digest (generally inhibits functions - exception is digestion)

Neuron

Basic cell of the NS

Dendrites

Receive incoming neurotransmitters

Axon

Action potential travels down this

Myelin Sheath

Protects axon, speeds up action potential

Sensory neurons

Receive sense signals from environment, send signals TO brain

Motor neurons

Signals to move, send signals FROM brain

Interneurons

Cells in spinal cord/brain responsible for reflex arc

Reflex arc

Important stimuli skips the brain and routes through the spinal cord for immediate reactions (ex. hand on a hot flame)

Glia

Support cells - give nutrients and clean up around neurons

Neural Firing with Action Potential

Ions move across membrane, send electrical charge down the axon

Resting potential

Neuron maintains a -70mv charge when not doing anything

Depolarization

Charge of a neuron briefly switches from (-) to (+) due to sodium rushing in, triggers the action potential

Threshold of depolarization

Stimulus strength must reach this point to start the action potential.

All or nothing principle

Stimulus must trigger the action potential past its threshold, but does not increase the intensity or speed of the response (ex. flush the toilet)

Refractory period

Neuron must rest and reset before it can send another action potential (ex. toilet resets)

Neurotransmitters

Chemicals released in synaptic gap, received by neurons. Classified as excitatory (increase action potentials in other neurons) or inhibitory (decrease action potentials)

GABA

Major inhibitory neurotransmitter

Surplus of GABA

Drowsiness, muscle weakness, cognitive impairment due to reduced brain activity

Deficit of GABA

Anxiety, insomnia, chronic pain, depressed mood, seizures

Glutamate

Major excitatory neurotransmitter

Surplus of glutamate

Seizures, migranes

Deficit of glutamate

Cognitive impairments, learning deficits

Dopamine

Inhibitory - short term rewards and fine movement - in hypothalamus, associated with addiction

Surplus of dopamine

Schizophrenia, euphoria, overly-energized, difficulty sleeping, psychosis

Deficit of dopamine

Parkinson's disease (tremors and muscular rigidity), ADHD

Serotonin

Inhibitory - long-term moods, emotion, sleep

Surplus of serotonin

Serotonin Syndrome (nervousness, nausea, tremors, disorientation, high blood pressure, seizures)

Deficit of serotonin

Depression, anxiety, worry, nervousness, sleep difficulties

Acetylcholine (ACh)

Excitatory - memory and movement

Surplus of ACh

Blurred vision, nausea, slow heart rate, breathing difficulties, paralysis

Deficit of ACh

Myasthenia Gravis (muscle weakness), Alzheimer's (memory loss)

Norepinephrine

Excitatory - alertness, sympathetic NS