Unit 1 Part 1

Module 1.1:

Psychology’s biggest issues: are our human traits present at birth (nature) or do they develop through experience (nurture)

Today’s science views traits + behaviors as arising from interaction of nature & nurture

Evolutionary Psychology: study of evolution of behavior & mind; uses principles of natural selection 

• Charles Darwin’s theory of Natural Selection: principle that inherited traits enable an organism to survive + reproduce in particular environment will most likely be passed onto succeeding generations

• Behavior Genetics: study of relative power / limits of genetic + environmental influences on behavior (how genetics / environment influence behavior)

Understanding Human Nature:

• Evolutionary psychologists use Darwin’s principle of natural selection to understand behavior + mental processes.

• Organism’ varied offspring compete for survival --- mutation (random error in gene replication that leads to a change)

• Certain biological and behavioral variations increase organisms; reproductive & survival chances

• Offspring that survive more likely to pass on genes

• Eugenics: aims to “eradicate” genetic defects & improve genetic makeup through selective human breeding 

Environment and Heredity:

• Behavior genetics: explores genetic + human environment basis of human differences

  • Environment: NONgenetic influence (i.e. prenatal nutrition, experiences of people and things around us)

  • Heredity: genetic transfer of characteristics from parent → offspring

• Ex: 2 people may have gene for high intelligence level, but individual with lack of stimulation to academically excel may not reach full potential, while individual constantly motivated intellectual will be more likely to intellectually excel

Genes: Our Life Code:

• Genes: biochemical units of heredity

• Genome: entire set of DNA / genetic information found in organism 

  • humans + chimps ~96% the same genetically

• no one single gene that will predict your intelligence, personality, or sexual orientation

Twins & Adoption Studies:

• 1 of ways to study nature vs. nurture argument

• Identical (monozygotic) twins: individuals who developed from 1 fertilized egg that split in 2, creating 2 genetically identical organisms; may not always have equal number copies of genes repeated in genome

• Fraternal (dizygotic) twins: individuals who developed from separate fertilized eggs; genetically no closer than ordinary siblings but shared prenatal environment

• Twin studies: allow researchers to examine role of genes in development of trait or disorder; comparisons between monozygotic twins & dizygotic twins conducted to evaluate degree of genetic + environmental influence on specific trait

• Studies have shown that environment shared by a family’s children has little impact on their personality--- just because you’re raised in same environment does not mean you will have similar personality as your parents/siblings

Gene-Environment Interactions: 

• Interaction: interplay that occurs when effect of 1 factor (environment) depends on another factor (heredity)

  • Example: If you walk all summer barefoot your feet will become more callused. Your friend wears shoes and is tender-footed ---biological adaptation to environmental changes

• Epigenetics: study of molecular mechanisms by which environments can influence genetic expression

  • Example: If a child is sleep deprived or nutritionally deprived they might not reach their biological/genetic height

Module 1.2:

Nervous System: body’s speedy electrochemical communication network, consisting of all nerve cells of peripheral & central nervous system

• Central nervous system (CNS): brain, spinal cord

• Peripheral nervous system (PNS): sensory & motor neurons connecting CNS to rest of body

Nerves: bundle of axons that form neural cables connecting CNS with muscles, glands, sensory organs

• Sensory (afferent) neurons: carry incoming information from body’s tissues and sensory receptors to brain, spinal cord

• Motor (efferent) neurons: carry outgoing information from brain, spinal cord to muscles and glands

• Interneurons: within brain, spinal cord; communicate internally & process information between sensory inputs and motor outputs

Central Nervous System:

Brain: controls most of 5 functions of body, including awareness, movement, thinking, speech, 5 senses

Spinal cord: extension of brain; carries messages to / from brain to rest of body

• Reflex: simple, automatic response to sensory stimulus; Ex: knee-jerk stimulus

Module 1.3a:

Neural Impulse: 

Action potential: neural impulse; brief electrical charge that travels down axon (neurotransmitter transported from dendrites → terminal branches of axon → next neuron); will only be generated when excitatory impulses > inhibitory impulses

• Threshold:level of stimulation required to triggeraction potential

• Refractory period: brief resting pause after neuron has fired / initiated action potential (more difficult / impossible for neuron to produce another action potential during this time); subsequent action potentials cannot occur until axon returns to resting state; neuron cannot “re-fire” until it reaches refractory period; prevents action potential from happening too quickly again + signal moving backwards 

• All-or-Nothing response: neuron’s reaction of either firing or not firing depending on whether threshold is met (no partial responses); for a certain neuron, action potential stays the same regardless of strength of stimulus

How neurons communicate:

• Synapse (a.k.a. Synaptic gap, synaptic cleft): junction between axon tip of sending neuron + dendrite / cell body of receiving neuron 

• Neurotransmitters: chemical messengers that cross synaptic gap between neurons; released by sending neuron → neurotransmitters travel across synapse → bind to receptor sites of receiving neuron (influence whether receiving neuron will generate a neural impulse)

• Reuptake: neurotransmitters reabsorption by sending / presynaptic neuron (prevent accumulation of neurotransmitters in synapse → excessive / prolonged stimulation of postsynaptic neuron, terminates signaling by neurotransmitter once signal has been transmitted to postsynaptic neuron, allows neurons to recycle neurotransmitters)

Neurotransmitters:

Agonist vs. Antagonist:

• Agonist: molecule that ↑ action of neurotransmitter; usually has very similar structure to neurotransmitter allowing it to mimic actions of neurotransmitter by binding to specific brain receptors

  • Ex: morphine binds to neurons to heighten pleasure / decrease pain

• Antagonist: molecule that inhibits or blocks action of neurotransmitter

  • Ex: memantine blocks glutamate receptors in brain, helping reduce excitotoxicity (neuronal damage; associated with neurodegenerative diseases) 

Endocrine System:

• Body’s “slow” chemical communication system; set of glands, fat tissue that secrete hormones into bloodstream

  • Hormones: chemical messengers manufactured by endocrine glands that travel through bloodstream + affect other tissues 

• Hypothalamus: secretes hormones that stimulate / suppress release of hormones in pituitary gland

Module 1.3b:

Psychoactive Drug: chemical substance that alters brain, causing changes in perceptions + moods (i.e. seeing things that aren’t there, hearing things that aren’t there, distance / depth perception)

Substance Use Disorder: disorder characterized by continued substance use despite resulting life disruption; Ex: someone who continuously uses alcohol even if it may cost them their family, job, money etc.

Near-death experience: altered state of consciousness reported after “close brush with death”; often similar to drug-induced hallucination

Tolerance & Addiction:

• Tolerance: diminishing effect with regular use of same dose of drug → forces user to UP DOSAGE in order to experience drug’s effect; can also be built up with medication

• Addiction: compulsive substance use that continues despite harmful consequences; considered psychological disorder 

  • Gambling, video games, other behaviors = can be considered addictive

• Withdraw: discomfort and distress that follows discontinuing an addictive drug / behavior; physical / psychological symptoms after coming off a drug

Module 1.4a:

Biological Psychologist:

• Phrenology: proposed by Franz Gull; idea that studying bumps on skull would reveal person’s mental abilities & character traits; over time, proved to be FALSE

• ***Biological Psychologist (a.k.a. behavioral neuroscientist, neuropsychologist, behavior geneticist, physiological psychologist, or biopsychologist): studies link between biological (genetic, neural, hormonal) + psychological processes 

Biopsychosocial Approach:

• integrated approach; incorporates biological, psychological, & social-cultural levels of analysis

• Levels of analysis: differing complementary views (biological to psychological to social-cultural) / using different approaches to analyze given phenomenon

Power of Neuroplasticity:

• Neuroplasticity: brain’s ability to change + adapt to change, especially during CHILDHOOD, by reorganizing or building new pathways based on experience after damage

Types of Neural Measures:

Module 1.4b:

The Brain:

Hindbrain: consists of medulla, pons, cerebellum; directs essential survival functions (breathing, sleep, wakefulness, coordination, balance)

Midbrain: found atop brainstem; connects hindbrain with forebrain, controls some motor movement, transmits auditory & visual information

Forebrain: consists of cerebral cortex, thalamus, hypothalamus; manages complex cognitive activities, sensory & associative functions, voluntary motor activities 

**lower brain centers = hindbrain + midbrain

The Lobes of the Brain:

Association areas: reas of cerebral cortex not involved in primary motor functions, but involved in higher mental functions (learning, remembering, speaking, thinking)

Module 1.4c

Response to Damage:

• brain’s ability to repair itself / create new neural pathways 

• Neuroplasticity: ability of neural networks in brain to change thru growth / reorganization by modifying strength of existing synapses + forming new synaptic connections; can occur after serious damage, especially in young children, can help those with vision or hearing loss (brain enhances other sensory signals / inputs)

• Neurogenesis: formation of new neurons

Split Brain Procedure:

• Corpus Callosum: large band of neural fibers connecting 2 hemispheres + carrying messages between them; allow messages to be passed between 2 hemispheres → brain works as cohesive unit

• Split Brain: condition resulting from surgery that separates brain’s 2 hemispheres by cutting fibers (mainly those of corpus callosum); creates 2 separate brains that can no longer communicate → independent functioning of each hemisphere; commonly used to treat severe epilepsy

  • Split brain patients often have difficult time speaking fluently when objects presented in left visual field → right hemisphere is non-verbal + interprets left visual field

Left vs. Right Hemisphere traits: