Comprehensive Overview of Psychological Research Methods

Operational Definition

clear, precise, quantifiable definition of your variables - allows replication and collection of reliable data

Qualitative data

descriptive data (eye color)

Quantitative data

numerical data - IDEAL and necessary for statistics

Correlation

identify relationship between two variables

Directionality problem

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

3rd variable problem

different variable is responsible for relationship (ice cream and murder)

Positive Correlation

variables increase & decrease together

Negative Correlation

as one variable increases the other decreases

Independent Variable

purposefully altered by researcher to look for effect

Experimental Group

received the treatment (part of the IV); can have multiple experimental groups

Control Group

placebo, baseline (part of the IV); can only have 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

Double-Blind

experiment where neither the participant or the experimenter are aware of which condition people are assigned to (drug studies)

Single-Blind

only participant blind - used if experimenter can't be blind (gender, age, etc)

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 - increase chance of equal representation among groups

Naturalistic Observation

observe people in their natural settings

Case Study

Studies ONE person (usually) in great detail

Meta-Analysis

combines multiple studies to increase sample size and examine effect sizes

Descriptive stats

show shape of the data

Mean

Average (use in normal distribution)

Median

Middle number (use in skewed distribution)

Mode

occurs most often

Statistical Significance

results not due to chance, experimental manipulation caused the difference in means

Effect Size

data has practical significance - bigger = better

Confidentiality

names kept secret

Debriefing

must be told the true purpose of the study (done after for deception)

Self report bias

Errors when collecting survey data due to social desirability and wording effects.

Random Sample

Method for choosing participants for your study where everyone has a chance to take part, increasing generalizability.

Representative Sample

Sample that mimics the general population in terms of ethnicity, gender, and age.

Convenience Sample

Selecting participants based on availability, leading to less representativeness and generalizability.

Sampling bias

Occurs when the sample isn't representative due to convenience sampling.

Cultural norms

Behaviors of a particular group that can influence research results.

Experimenter bias

When the experimenter's expectations influence the outcome of the study.

Participant bias

When the participant's expectations influence the outcome of the study.

Cognitive bias

Bias in thinking or judgment.

Confirmation bias

The tendency to find information that supports preexisting beliefs.

Hindsight bias

The inclination to see events as having been predictable after they have already occurred.

Peer review

A process that research needs to undergo to ensure quality and validity.

Adequate sample sizes

A requirement for research to ensure that results are reliable and generalizable.

Heredity

How genes influence behavior.

Nature vs. Nurture

The debate regarding the relative contributions of heredity and environment to human behavior.

Twin / Adoption Studies

Research methods used to understand the influence of genetics and environment on behavior.

Central Nervous System (CNS)

Comprises the brain and spinal cord.

Peripheral Nervous System (PNS)

Consists of all nerves outside the CNS that relay information to and from the brain.

Somatic Nervous System

Part of the PNS responsible for voluntary movement and sensory information.

Autonomic Nervous System

Part of the PNS that controls involuntary organs.

Sympathetic Nervous System

Part of the autonomic nervous system that activates the fight or flight response.

Parasympathetic Nervous System

Part of the autonomic nervous system that promotes rest and digestion.

Neuron

The basic cell of the nervous system.

Dendrites

Parts of a neuron that receive incoming neurotransmitters.

Axon

The part of the neuron where the action potential travels down.

Myelin Sheath

A protective layer that speeds up the action potential along the axon.

Synapse

The gap between neurons.

Sensory neurons

Neurons that receive sensory signals from the environment and send them to the brain.

Motor neurons

Neurons that send signals from the brain to initiate movement.

Interneurons

Neurons in the spinal cord and brain responsible for reflex arcs.

Reflex arc

A neural pathway that bypasses the brain for immediate reactions.

Glia

Support cells that provide nutrients and clean up around neurons.

Action Potential

An electrical charge that travels down the axon when ions move across the membrane.

Resting potential

The state of a neuron when it maintains a -70mv charge.

Depolarization

The process where the charge of a neuron briefly switches from negative to positive.

Threshold of depolarization

The point that must be reached for an action potential to occur.

All or nothing principle

The principle that an action potential either occurs fully or not at all.

Refractory period

The time after an action potential during which a neuron cannot fire again.

Neurotransmitters (NT)

Chemicals released in the synaptic gap that are received by neurons.

GABA

The major inhibitory neurotransmitter.

Glutamate

The major excitatory neurotransmitter.

Dopamine

A neurotransmitter associated with reward and fine movement.

Serotonin

A neurotransmitter that regulates mood, emotion, and sleep.

Acetylcholine (ACh)

A neurotransmitter involved in memory and movement.

Norepinephrine

A neurotransmitter associated with the sympathetic nervous system.

Endorphins

decrease pain

Substance P

pain regulation (abnormality increases pain and inflammation)

Oxytocin

love, bonding, childbirth, lactation

Adrenaline

fight/flight

Leptin

makes you full (stops hunger)

Ghrelin

makes you hungry (turns you into a gremlin)

Melatonin

sleep

Agonist

drug that mimics a NT

Antagonist

drug that blocks a NT

Reuptake

Unused NTs are taken back up into the sending neuron.

Depressants

Decrease NS activity (alcohol)

Stimulants

Increase NS activity (caffeine & cocaine)

Hallucinogens

hallucinations and altered perceptions (Marijuana)

Opioids

relieve pain (endorphin agonists) (heroin)

Tolerance

Needing more of a drug to achieve the same effects

Addiction

must have it to avoid withdrawal symptoms

Withdrawal

symptoms associated with sudden stoppage

Cerebellum

movement, balance, coordination, procedural memory

Brainstem / Medulla

vital organs (HR, BP, breathing)

Reticular activating system

alertness, arousal, sleep, eye movement

Cerebral Cortex

outer portion of the brain - higher order thought processes

Amygdala

emotions, fear

Hippocampus

episodic and semantic memory

Hypothalamus

Reward/pleasure center, eating behaviors - link to endocrine system, homeostasis

Thalamus

relay center for all but smell

Pituitary gland

talks w/ endocrine sys and hypothalamus - release hormones

Occipital Lobe

vision