psych textbook notes

7/29/2019 Psych Textbook Notes

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Chapter 2 1/31/2013 10:30:00 PM

Key:

O: Optional, it is your choice whether to read it

R: Read the material, but you wont be tested on it

M: Learn only the major points of the section

D: Learn the material in detail (but not names or individual studies)

Pp. 49-54: D

Neurons

1. What are neurons and how do they transmit information?o Neurons: nerve cells that are building blocks of our bodys

neural info system

Sensory: carry messages from the bodys tissues andsensory organs to the brain and spinal cord for

processing

Nervous system has a few million of these Motor: carries instruction from the brain and spinal cord

to the bodys tissues

Few million Interneurons: processes information from the sensory

and motor neurons in the brains internal

communication system

Our complexity resides here Billions and billions

o Each aspect of a neuron consist of a cell body and itsbranching fibers

Dendrite: fibers that receive info and conduct it towardthe cell body

Listens to axons Short

Axon: passes the message from dendrites along to theother neurons or muscle glands

Speaks to dendrites Long (project several feet through the body) Myelin sheath: layer of fatty tissue that insulates

the axons of some neurons and helps speed their

impulses


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Laid down (forming) until up to age 25 If sheath degenerates, multiple sclerosis

results (communication to muscles slow and

eventually can lose muscle control)

o Neural impulses travel at speeds ranging from 2 mph to 200+mph depending on the type of fiber

Brain activity is measured in milliseconds Brain is more complex than a computer but slower

o Neurons transmit messages when stimulated by signals fromour senses or when triggered by chemical signals from

neighboring neurons

Action potential: impulse of a brief electrical charge thattravels down its axon

Generate electricity from chemical events Involves the exchange of ions Resting potential: when fluid inside of a resting

axon has an excess of charged ions while the

outside has more + charged ions

Axon surface is selectively permeableo Process of neuron fire

1. Axon open its gates and + charged sodium ions floodthrough the membrane depolarization other axonchannels to open like a domino effect

2. Resting pause (refractory period) where the neuronpumps + ions back outside to fire again

o Excitatory and inhibitory signals from neurons If excitatory signals minus inhibitory signals exceed a

minimum intensity (threshold), it triggers an action

potential

o Neurons reaction is an all or none response 2. How do nerve cells communicate with other nerve cells?

o Synapse: meeting point between neurons Coined by Sir Charles Sherrington, who noticed that

neural impulses were taking a long time to travel a

neural pathway and inferred there must be a brief

interruption


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o Synaptic cleft: a gap that separates the axon terminal fromthe receiving neuron (less than a millionth of an inch wide)

o Neurotransmitters: chemical messengers released when anaction potential reaches the terminals at an axons end

Bind to receptor sites on the receiving neuron Unlocks tiny channels at the receiving site, letting

electrically charged atoms flow in

Reuptake: process in which sending neurons reabsorbthe excess neurotransmitters

3. How do neurotransmitters influence behavior, and how do drugsand other chemicals affect neurotransmission?

o Acetylcholine (ACh) Best understood neurotransmitter Role in learning and memory Messenger at every junction between a motor neuron

and skeletal muscle

Causes muscle contractiono Endorphins

One naturally occurring opiates that body produces Help with painkilling

o Drugs and other chemicals affect brain chemistry at synapses(amplifying or blocking neurotransmitter activity)

Agonist molecule: either mimic effects ofneurotransmitter or block its reuptake

Antagonist molecules: block a neurotransmittersfunctioning

Pp. 55- 58 (top): M

The Nervous System

What are the functions of the nervous systems main divisions?o Nervous system: bodys speedy electrochemical

communications network

o Central Nervous System (CNS): brain + spinal cord Communicates with bodys sensory receptors, muscles

and glands via the PNS

Neuron cluster work in groups called neural networks


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Spinal cord is the information highway connecting thePNS to brain

Governs reflexeso Peripheral Nervous System (PNS): somatic + autonomic

Somatic nervous system Enables voluntary control of our skeletal muscles

Autonomic nervous system Controls glands and the muscles of our internal

organs

Influences functions as glandular activity,heartbeat, and digestion

2 basic functions Sympathetic nervous system: arouses and

expends energy

o If something alarms, enrages, orchallenges you

Parasympathetic nervous system: oppositeo Conserves energy and calms you

Pp. 61-62 (top): M

The Brain

Brain + body = mind


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How do neuroscientists study the brains connections to behaviorand mind?

o We can now lesion (destroy) tiny clusters of normal ordefective brain cells

o Electroencephalogram (EEF): amplified read-out of the wavesof electrical activity in the brains neurons

o Positron emission tomography scan (PET): depict brainactivity by showing each brain areas consumption of sugar

glucose (its chemical fuel)

o Magnetic resonance imaging (MRI): scanning of brain thatprovides detailed pictures of the brains soft tissues

o Functional MRI (fMRI): reveals the brains functioning as wellas its structure

Pp. 68-81: M

The Cerebral Cortex

Cerebral cortex: thin surface layer of interconnected neural cellso Ultimate control and info processing center

What functions are served by the various cerebral cortex regions?o Glial cells

provide nutrients and insulating myelin guide neural connections mop up ions and neurotransmitters play a role in learning and thinking

o Parts of the brain Frontal lobes (behind your forehead) Parietal lobes (at the top and to the rear) Occipital lobes (at the back of your head) Temporal lobes (just above ears)

*lobes are separated by prominent fissures (geographic

subdivisions)

o Functions of the cortex Motor function

Motor cortex (left hemisphere section of braincontrols the bodys right side)

Controls the actions of the body


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Sensory function Sensory cortex (left hemisphere section receives

input from the bodys right side)

Gives you the senses of the body Association areas

Link sensory inputs with stored memories Found in all four lobes Enable judgment, planning, and processing of

new memories

To what extent can a damaged brain reorganize itself?o Plasticity: brains ability to modify itself after some type of

damage

Some neutral tissue can reorganize in response todamage

Constraint-induced therapy: aims to rewire brains byrestraining a fully functioning limb and forcing use of

the bad hand or the uncooperative leg

o Amount of plasticity correlates with amount and type ofdamage

What do split brains reveal about the functions of our two brainhemispheres?

o Severing the corpus callosum 1961: 2 LA neurosurgeons, Vogel and Bogen,

speculated that major epileptic seizures were caused by

an amplification of abnormal brain activity bouncing

between two cerebral hemispheres

Corpus callosum: wide band of axon fibers connectingthe two hemispheres and carrying messages

Splitting brains did not eliminate seizures, but thepatients were surprisingly normal

o Understanding the hemispheres complementary functions Left hemisphere is more active when a person

deliberates over decisions (rational)

Right hemisphere understands simple requests, easilyperceives objects, and is more engaged when quick,

intuitive responses are needed


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Undivided brains Right hemisphere

Perceptual tasks (brain waves, bloodflow) Makes inferences Helps modulate our speech to make

meaning clear

Orchestrate sense of self Left hemisphere

Speaks or calculates Makes quick, literal interpretations of

language

How does handedness relate to brain organization?o 90% of us are primarily right-handed

Right-handers process speech primarily in the lefthemisphere (tends to be slightly larger)

Left handers more diverse


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Chapter 4 1/31/2013 10:30:00 PM

Pp. 134-135 (top): M

Behavior Genetics

What are genes and how do behavior geneticists explain ourindividual differences?

o Each parent gives you 23 chromosomes (composed of DNA) DNA composed of genes, which can be active or inactive Environmental factors can turn on genes

o Most traits are influenced by multiple genesPp. 135 (bottom)-143 (top): D

Twins

Identical twins (genetically identical; develop from a single fertilizedegg that splits in two)

o Have the same genes but dont always have the samenumber of copies of those genes (explains why one twin may

be more at risk for a certain illness)

o Most share a placenta, but some have separate placentas Fraternal twins (develop from separate fertilized eggs but share a

fetal environment; not more genetically similar than normal

siblings)

Shared genes can lead to shared experienceso Identical twin with Alzheimers disease, other twin has 60%

chance of getting it too

o Fraternal twin with Alzheimers disease, other twin has 30%chance of getting it too

o Divorce rates are more similar for identical than fraternaltwins

Separated twinso Ex: Jim Lewis and Jim Springer

Twins separated 37 days after birth and are prettymuch the same person, down to the names of their

sons and dogs

Biological vs. Adoptiveo Genetic relatives: biological parents and siblings)o Environmental relatives: adoptive parents and siblings


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o People who grow up together dont necessarily resemble eachother in personality

o Genetic leash may limit the family environments influence onpersonality, but parents do influence their childrens attitudes,

values, manners, faith, and politicso Adoptive parents may treat the kids better than biological

would have (adoptive parents are screened and natural are

not)

Temperament and Heredity

Temperament: emotional excitability (whether reactive, intense,fidgety, easygoing, quiet, placid)

o Ex: infants Difficult more irritable, intense, and unpredictable Easy cheerful, relaxed, and predictable in feeding and

sleeping

Slow-to-warm-up tend to resist or withdraw from newpeople and situations

o Temperament differences tend to persist Heredity predisposes temperament differences

Heritability

What is heritability and how does it relate to individuals andgroups?

o Heritability: the extent to which variation among individualscan be attributed to their differing genes

Genetic influence explains 50% of the observedvariation among people

Ex: if the heritability of intelligence is 50%, this doesnot mean that your intelligence is 50% genetic

***WE CAN NEVER SAY WHAT PERCENTAGE OF ANINDIVIDUALS PERSONALITY OR INTELLIGENCE IS

INHERITED

Heritability refers to the extent to which differencesamong people are attributable to genes

Heritability increases if the environment in which thepeople are exposed to are equal

o Group differences


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Heritable individual differences need not imply heritablegroup differences

One person acting a certain way/having certaintraits doesnt imply that the entire group is the

same way as wello Nature and Nurture

Among our similarities, the most important is ourenormous adaptive capacity

Ex: go barefoot for a summer and youll developtoughened, callused feet (adaptation to friction)

Genes are self-regulatingo Gene-environment Interaction

Genes and experience interact Baby genetically predisposed to be attractive,

sociable, and easygoing vs. baby and was not

Baby 1 gets/seeks more attention and thusgrows into an even more sociable person

Baby 2 does not and thus deviates morefrom baby 1

Evocative interaction: actions and experiences thathappen to a person that causes them to react in a

certain way and influences their personalityMolecular Genetics

What is the promise of molecular genetics research?o Molecular genetics seeks to identify specific genes influencing

behavior

o Goals: To find some of the many genes that influence normal

human traits

body weight, sexual orientation, and extraversion To explore the mechanisms that control gene

expression

o Search links between certain genes or chromosome segmentsand specific disorders

Pp. 143 (bottom)-146 (top): M


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Evolutionary Psychology

How do evolutionary psychologists use natural selection to explainbehavior tendencies?

o Darwins principle of natural selection Organisms varied offspring compete for survival Certain biological and behavioral variations increase

their reproductive and survival chances in their

environment

Offspring that survive are more likely to pass theirgenes to ensuing generations

Over time, population characteristics may changeo Natural Selection and Adaptation

When certain traits are selected (by conferring areproductive advantage to an individual or a species)

those traits over time will prevail

Mutations: random errors in gene replication We adapt very easily, contributing to our fitness our

ability to survive and reproduce

o Evolutionary Success Helps Explain Similarities Our shared human traits are shaped by natural

selection acting over the course of human evolution

We have a common logic across cultures No more than 5% of the genetic differences among

humans arise from population group differences

95% of genetic variation exists within populationso Outdated tendencies

Sweets and fats used to protect ancestors from famine,which is why we love them so much

We are biologically prepared for a world that no longerexists

Human Sexuality

How might an evolutionary psychologist explain gender differencesin mating preferences?

o Males are more likely than females to initiate sexual activityo Men often misattribute womens friendliness as sexual

advancements


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Natural selection and mating preferenceso Womens approach to sex is more rational while mens are

more recreational

o Men are more attracted to women with signs of fertility butwith a youthful appearance

o Women are attracted to men who seem mature, dominant,bold, and affluent

o Nature selects behavior that increases the likelihood ofsending their genes to the future

Pp. 148 (bottom)-152: M

Parents and Peers

To what extent are our lives shaped by early stimulation, byparents, and by peers?

o Early Stimulation Both nature and nurture sculpt our synapses Our experiences trigger a pruning process Brains development does not end with childhood

o Parents Power of parenting shape our differences Parenting accounts for less than 10% of shaping the

childrens personalitieso Peer Influence

Peers have high power Peer pressure


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1/31/2013 10:30:00 PM

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