Research Design and Biological Basis Notes
Research Design
Hypothesis: A tentative explanation that must be falsifiable.
Operational Definition: A clear, precise, and quantifiable definition of variables to allow replication and reliable data collection.
Qualitative Data: Descriptive data (e.g., eye color).
Quantitative Data: Numerical data, ideal for statistics.
Population: The entire group to which the research could apply.
Sample: The specific subset of the population chosen for the study.
Research Designs
Correlation
Definition: Identifies the relationship between two variables.
Advantage: Useful when experiments are unethical.
Disadvantage: Correlation does not equal causation.
Directionality Problem: Uncertainty about which variable causes the other (e.g., depression and low self-esteem).
Third Variable Problem: A different variable is responsible for the observed relationship (e.g., ice cream sales and murder rates).
Positive Correlation: Variables increase or decrease together.
Negative Correlation: As one variable increases, the other decreases.
Strength of Correlation: The closer the absolute value is to 1, the stronger the relationship, regardless of the sign. Cannot be < or > than 1.
Graphical Representation: Stronger relationships appear as tighter clusters on a graph.
Experiments
Definition: Purposefully manipulate variables to determine cause and effect.
Advantage: Establishes cause and effect.
Disadvantage: Can be unethical or too artificial.
Independent Variable: The variable altered by the researcher.
Experimental Group: Receives the treatment (part of the IV); can have multiple experimental groups.
Control Group: Receives a placebo or baseline treatment (part of the IV); can only have one control group.
Dependent Variable: The variable measured; dependent on the independent variable.
Placebo Effect: An effect caused by the placebo itself.
Double-Blind Study: Neither the participant nor the experimenter knows the condition to which people are assigned.
Single-Blind Study: Only the participant is blind; used when the experimenter cannot be blind.
Confound: An error or flaw accidentally introduced into the study.
Random Assignment: Assigning participants to control or experimental groups randomly to increase the chance of equal representation.
Other Study Types
Naturalistic Observation: Observing people in their natural settings.
Advantage: Real-world validity.
Disadvantage: No cause and effect can be established.
Case Study: Studying one person in great detail.
Advantage: Collects lots of information.
Disadvantage: No cause and effect can be established.
Meta-Analysis: Combines multiple studies to increase sample size and examine effect sizes.
Statistics
Descriptive Stats: Show the shape of the data.
Measures of Central Tendency:
Mean: Average, best used in normal distribution.
Median: Middle number, best used in skewed distribution.
Mode: The number that occurs most often.
Bimodal: Two modes, usually indicating good and bad scores.
Skews:
Negative Skew: The mean is to the left, and the mode is to the right.
Positive Skew: The mean is to the right.
Measure of Variation:
Range: Distance between the smallest and largest numbers.
Standard Deviation: Average amount the scores are spread from the mean; a bigger number indicates more spread.
Inferential Statistics: Establishes significance.
Statistical Significance: Results are not due to chance; the experimental manipulation caused the difference in means.
P-value: p<.05 indicates statistical significance; the smaller, the better.
Effect Size: Data has practical significance; bigger is better.
Ethical Guidelines (IRB Approval Needed for People)
Confidentiality: Names are kept secret.
Informed Consent: Participants must agree to be part of the study.
Informed Assent: Minors and their parents must agree.
Debriefing: Participants must be told the true purpose of the study, especially after deception.
Deception: Must be warranted.
No Harm: No mental or physical harm should come to participants.
Additional Vocabulary
Surveys: Usually turned into correlation.
Self-Report Bias: Errors when collecting survey data.
Social Desirability: People lie to look good.
Wording Effects: How a question is framed can impact answers.
Random Sample (Selection): Everyone has a chance to take part; increases generalizability.
Representative Sample: Sample mimics the general population.
Convenience Sample: Select participants on availability; less representative and less generalizable.
Sampling Bias: Sample isn't representative due to convenience sampling.
Cultural Norms: Behaviors of a particular group can influence research results.
Experimenter Bias/Participant Bias: Experimenter/participant expectations influence the outcome.
Cognitive Bias: Bias in thinking/judgment.
Confirmation Bias: Find information that supports preexisting beliefs.
Hindsight Bias: "I knew it all along."
Overconfidence: Overestimate our knowledge/abilities.
Hawthorne Effect: People change behavior when watched.
Research needs peer review and adequate sample sizes.
Biological Basis Pillar
NT = neurotransmitter, AP = action potential, NS = nervous system
Heredity vs Environment
Evolutionary Psychology: Study how natural selection influences behavior.
Heredity (Nature): How genes influence behavior.
Environment (Nurture): How outside situations influence behavior (e.g., school).
Nature vs. Nurture: Answer is both.
Twin/Adoption Studies:
Genetics: Identical twins will have a higher percentage of also developing a disease.
Environment: Identical twins raised in different environments show differences.
Nervous System
Central NS: Brain and spinal cord.
Peripheral NS: Rest of the NS relays to the Central NS.
Somatic NS: Voluntary movement; has sensory and motor neurons.
Autonomic NS: Involuntary organs (heart, lungs, etc.).
Sympathetic NS: Fight/flight (generally activates, exception digestion).
Parasympathetic NS: Rest/digest (generally inhibits, exception digestion).
Neuron and Neural Firing
Neuron parts are described in the text.
Neuron: Basic cell of the NS.
Dendrites: Receive incoming NTs.
Axon: AP travels down this.
Myelin Sheath: Speeds up AP down axon, protects axon.
Synapse: Gap between neurons.
Sensory Neurons: Receive sense signals from the environment and send signals to the brain.
Motor Neurons: Signals to move, send signals from brain.
Interneurons: Cells in spinal cord/brain responsible for reflex arc.
Glia: Support cells that give nutrients and clean up around neurons.
Neurons Fire with an Action Potential
Ions move across the membrane, sending an electrical charge down the axon.
Resting Potential: Neuron maintains a charge when not doing anything.
Depolarization: The charge of neuron briefly switches from negative to positive, triggers the AP.
Threshold of Depolarization: Stimulus strength must reach this point to start the AP.
All or Nothing Principle: Stimulus must trigger the AP past its threshold but does not increase the intensity or speed of the response.
Refractory Period: Neuron must rest and reset before it can send another AP.
Neurotransmitters (NT)
Chemicals released in the synaptic gap, received by neurons, and classified as excitatory or inhibitory.
GABA: Major inhibitory NT.
Glutamate: Major excitatory NT.
Dopamine: Reward (short term) & fine movement; in hypothalamus, associated with addiction.
Serotonin: Moods (long-term), emotion, sleep; in amygdala, too little assoc. w/ depression.
Acetylcholine (ACh): Memory and movement; in hippocampus, assoc. w/ Alzheimer's.
Norepinephrine: Sympathetic NS; too little assoc. w/ depression.
Endorphins: Decrease pain.
Substance P: Pain regulation (abnormality increases pain and inflammation).
Hormones
If not in the nervous system, it's a hormone.
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.
Reflex Arc: Important stimuli skips the brain and routes through the spinal cord for immediate reactions.
Agonist: Drug that mimics a NT.
Antagonist: Drug that blocks a NT.
Reuptake: Unused NTs are taken back up into the sending neuron. Antidepressants cause reuptake inhibition.
Psychoactive Drugs
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.
The Brain
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; includes limbic system, lobes, corpus callosum.
Limbic System
Amygdala: Emotions, fear.
Hippocampus: Episodic and semantic memory.
Hypothalamus: Reward/pleasure center, eating behaviors, link to the endocrine system, homeostasis.
Thalamus: Relay center for all senses but smell.
Pituitary Gland: Talks with endocrine system and hypothalamus; releases hormones.
Lobes
Brain lobes are described in the text..
Occipital Lobe: Vision.
Frontal Lobe: Decision-making, planning, judgment, movement, personality, language, executive function.
Prefrontal Cortex: Front of the frontal lobe; executive function.
Motor Cortex: Back of the frontal lobe; map of our motor receptors; controls skeletal movement.
Parietal Lobe: Sensations and touch; controls association areas.
Somatosensory Cortex: Map of our touch receptors.
Research Design
Hypothesis: A testable explanation that can be proven wrong.
Operational Definition: How you'll measure variables clearly, so others can repeat your study.
Qualitative Data: Descriptive data (like colors or feelings).
Quantitative Data: Numerical data (numbers), good for stats.
Population: The whole group you're interested in.
Sample: A smaller group from the population that you study.
Research Designs
Correlation
Definition: Shows if two things are related.
Advantage: Useful when you can't do experiments for ethical reasons.
Disadvantage: Just because two things are related doesn't mean one causes the other.
Directionality Problem: Not sure which thing is causing the other.
Third Variable Problem: Something else might be causing both things.
Positive Correlation: Both things go up or down together.
Negative Correlation: As one thing goes up, the other goes down.
Strength of Correlation: The closer to 1 (positive or negative), the stronger the relationship. It cannot be.
**