What is the relationship between heredity and environment in shaping behavior
Behavior and mental processes result from an interaction between heredity (genes) and environment (experiences). Neither acts alone; they influence each other dynamically.
Define Heredity
Transmission of traits from parents to offspring through genes.
Define Environment
External factors (culture, family, experiences) that influence development
What is the Evolutionary Perspective
Explains behavior through principles of natural selection and adaptation. Traits that enhance survival and reproduction are passed on
What is Natural Selection
Process where traits that improve survival/reproduction become more common in a population over generations
Define Genes
Units of heredity that code for traits
Define Genome
Complete set of genetic material in an organism
What is Nurture vs. Nature
- Nature: Behavior shaped by genetics and biology.
- Nurture: Behavior shaped by environment and experiences.
- Modern View: Both interact—genes set potential, environment influences expression (supported by twin/adoption studies and epigenetics).
What is Eugenics
A controversial movement advocating selective breeding to improve genetic quality of humans
What are Twin Studies and Adoption Studies
- Compare identical (MZ) and fraternal (DZ) twins to assess genetic influence.
- Adoption Studies: Compare adopted children to biological and adoptive parents to separate genetic vs. environmental effects.
Identical vs. Fraternal Twins
- Identical (Monozygotic): Share 100% of genes.
- Fraternal (Dizygotic): Share ~50% of genes.
What is Epigenetics
Study of how environment can influence gene expression without changing DNA sequence
What is the Nervous System
Network of cells that transmit signals between body parts and the brain; controls behavior and mental processes
What is the Central Nervous System (CNS
Composed of the brain and spinal cord; processes information and directs responses
What is the Peripheral Nervous System (PNS)
All nerves outside the CNS; connects CNS to limbs and organs
What is the Somatic Nervous System
Part of PNS; controls voluntary movements and transmits sensory information
What is the Autonomic Nervous System (ANS)
Part of PNS; controls involuntary functions (heart rate, digestion). Includes sympathetic and parasympathetic systems
Sympathetic Nervous System
Activates “fight or flight” response
Parasympathetic Nervous System
Promotes “rest and digest” functions
What is a Reflex
Automatic response to a stimulus, processed by the spinal cord without brain involvement
What is a neuron
Basic cell of the nervous system that transmits information through electrical and chemical signals
Main parts of a neuron
- Cell Body: Contains nucleus
- Dendrites: Receive signals.
- Axon: Sends signals.
- Myelin: Speeds transmission.
- Synapse: Gap between neurons.
Types of neurons
- Sensory: Carry info to CNS.
- Motor: Carry commands from CNS.
- Interneurons: Connect neurons within CNS.
What are glial cells
Support neurons, provide nutrients, remove waste, form myelin
What is an action potential
Electrical impulse traveling down axon; follows all-or-nothing principle
ey steps in neural transmission
- Resting potential → Threshold → Depolarization → Action potential → Refractory period → Neurotransmitter release → Reuptake.
What is reuptake
Process where neurotransmitters are reabsorbed by the sending neuron.
Excitatory vs. Inhibitory neurotransmitters
- Excitatory: Increase likelihood of firing (e.g., Glutamate).
- Inhibitory: Decrease likelihood (e.g., GABA).
Examples of neurotransmitters
- Dopamine: Reward, movement.
- Serotonin: Mood, sleep.
- Acetylcholine: Muscle action.
- Endorphins: Pain relief.
- Norepinephrine: Alertness.
Endocrine system role
Releases hormones (e.g., adrenaline, oxytocin, melatonin) that influence behavior and mental processes.
How do psychoactive drugs affect neurotransmission
- Agonists: Mimic neurotransmitters.
- Antagonists: Block receptors.
-Reuptake inhibitors: Prevent reabsorption.
Types of psychoactive drugs
- Stimulants: Increase activity (caffeine, cocaine).
- Depressants: Slow activity (alcohol).
- Opioids: Pain relief (heroin).
- Hallucinogens: Alter perception (LSD, marijuana)
What are tolerance, addiction, and withdrawal
- Tolerance: Need more for same effect.
- Addiction: Compulsive use despite harm.
- Withdrawal: Negative symptoms when stopping.
What is the Brain Stem
Controls basic life functions (breathing, heart rate). Includes medulla oblongata, pons, and midbrain
What is the Reticular Activating System
Network in brainstem; regulates arousal, attention, and sleep-wake cycles.
What is the Cerebellum
Coordinates balance, posture, and fine motor movements
What is the Cerebral Cortex
Outer layer of forebrain; involved in higher-order functions like thinking, planning, and language.
What is Split Brain Research
tudies on patients with severed corpus callosum show hemispheric specialization (left = language, right = spatial)
Areas of the brain that affect language
- Broca’s Area: Speech production.
- Wernicke’s Area: Language comprehension.
Damage → aphasia.
Major lobes of the brain
- Frontal: Decision-making, motor cortex.
- Parietal: Sensory info, somatosensory cortex.
- Temporal: Hearing, language.
- Occipital: Vision.
What is the Limbic System
Emotional processing and memory. Includes amygdala, hippocampus, hypothalamus, thalamus.
What is Brain Plasticity
Ability of brain to reorganize and adapt after injury or experience
Common brain imaging techniques
- EEG: Electrical activity.
- MRI/fMRI: Structure & function.
- PET: Metabolic activity.
- CT: X-ray imaging.
- MEG: Magnetic fields.
What are Lesions
Damage or surgical removal of brain tissue used to study the function of specific areas
What are Case Studies in Brain Research
In-depth analysis of individuals with brain injuries or abnormalities to understand brain-behavior relationships