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Summary Introduction to Psychology (P_BINLPSY)
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Summary including lectures notes and summarised large parts of the book Psychological Science (2017 edition).
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Introduction to PsychologySummary – exam 23 october 2017
Genes and evolution (p. 3-6; 75-76 & 115-126)
★ Psychological science – the study, through research, of mind, brain and behavior ® why needed? ®
common sense fails
The genetic basis: does a violent person have violent genes?
70’s no! violence > caused by environment
09’s yes! violence > entirely caused by genes
today partly violence > caused by genes + environment
HUMAN BODY ® CELL (NUCLEUS) ® CHROMOSOME ® DNA ® GENE
★ Genes – meaningful sections of DNA molecules ® help cell function, provide info about making
protein (what/when/where)
★ Gene expression – whether a gene is turned on or off
are they being transcribed into an amino acid sequence? Turned on ® yes / turned off ® no
Some genes are expressed all the time, some are not; controlled by biochemical environment inside cell
★ Genome – complete set of DNA Influenced by biochemical
★ Genotype – the complete makeup of an organism environment outside cell/timing/
★ Phenotype – the observable characteristics of an organism overall environment/behavior
phenotype = genotype x environment
★ Dominant gene –from either parent ® expressed whenever it’s present
★ Recessive gene – only expressed when matched with similar gene from other parent
★ Polygenetic inheritance – when a population displays a range of variability for a certain characteristic
polygenetic inheritance = environment x multiple gene pairs
Darwin’s evolution theory – FUNDAMENTAL
Natural selection, 3 conditions:
1. Variation
2. Individuals with certain trait survive + reproduce better than others
3. The trait associated with this advantage is passed from parents to offspring.
9 specific trait will be better represented in next generation
What matters = survival of genes NOT survival of individuals
Evidence for evolution
• Fossil record – suggest gradual changes
• Resemblance between genomes of various organisms – ex. 2 chromosomes bonobo = fused in human
★ Pseudogenes – genes with no function
• Distribution of species across the world – continental island vs oceanic islands
Nature VS Nurture
1 (continuous interaction)
Who we are is determined by how our genes are expressed in distinct environments.
,Violent person – violent genes?
Genes 1 environment 1 criminal behavior
MAOA allele higher probability of
for low MAO 1 severe maltreatment 1 being convicted of
activity violent crimes
★ Behavioral genetics – field of scientific research that researches the nature and origin of human
behavior
Uses twin studies and adoption studies
Heritablity
★ Heritability – the proportion of a specific trait in a population due to genetics
$%&%'() *+,(+&)%
𝐻= heredity – individual / heritability – population
-.%&/'01() *+,(+&)%
★ Epigenetics – the study of how environment effects genetic expression
Experimental methods concern altering or changing the genes using
★ Knockout – particular genes are turned off/removed from the genome/disrupted
★ Optogenetics – control when a neuron fires using light
Biology and Behavior (p. 75-114)
Nervous system building blocks = glia & neurons = white ®
★ Neuron – cell that is specialized in receiving & sending information
• There’s different types of neurons
★ Sensory neurons – detect information from physical world and pass it on
to brain
★ Motor neurons – direct muscles to contract or relax ® produce movement
★ Interneurons – communicate within
local or short-distance circuits Structure of a neuron
Communication between neurons
★ rest potential – electrical value of inside
membrane compared to outside = - 70 mV
★ threshold = -55 mV
★ action potential = +40 mV
Action potential exists bc of occurance of a change
in cell membrane ® WHY?
1. Ion channels for sodium open (Na+)
2. Na+ flows in, inside becomes less negative, if it
reaches -55 mV it goes all the way and becomes positive (+40 mV)
3. Na+ channels close
4. Potassium (K+) ions go outwards, inside becomes negative again
1 – restpotential
2 – depolarization = Na+ into neuron
3 – repolarization = K+ out of neuron
4 – hyperpolarization = Na+ out, K+ in
,★ All-or-none law: neurons either fire or they don’t fire, they can’t fire a little bit
o Intensity varies by
§ Variation in number of neurons firing
§ Variation in firing rate of neuron
Interaction between neurons
Via synapses & neurotransmitters
1. Action potential enters axon terminal
2. Causes vesicles (containing neurotransmitters) to fuse to
presynaptic membrane and release neurotransmitters into
synapse
3. Neurotransmitters bind to (their typical) postsynaptic
receptors, which again triggers sodium ions to flow into the
membrane and changes the membrane potential of the
next neuron, so it gives on the action potential
Neurotransmitters….
• Lock-and-key model
• Effect is terminated by reuptake, enzyme deactivation or autoreception
• Can cause excitatory or inhibitory signal
Acetylcholine Motor control over muscles, Norepinephrine Arousal/vigilance/attention
learning/memory/sleeping/dreaming
Serotonin Emotional states and Dopamine Reward and
impulsiveness/dreaming motivation/motor control
over voluntary movement
GABA Inhibition of action Glutamate Enhancement of action
potentials/anxiety reduction potentials/learning and
Endorphins Pain reduction/reward memory
Drugs
Agonists Antagonists
• Increase of precursor • Decrease of precursor
• Counteracting the clean-up enzyme • Increase effectiveness clean-up enzyme
• Blocking re-uptake • Enhance the reuptake
• Mimicking the transmitter’s action • Blocking of receptors
Nervous system
NERVOUS
SYSTEM
Ways the brain communicates with the body: somatic
CENTRAL PERIPHERAL nervous system, autonomic nervous system and
NERVOUS
SYSTEM (CNS)
NERVOUS
SYSTEM (PNS)
endocrine system
Somatic Nervous System – voluntary behavior
Somatic Nervous
Autonomic Autonomic Nervous System – internal environment
brain Nervous System
System (SNS)
(ANS) sympathetic – action (dilates pupil-fast
heartbeat-contracts vessels-inhibits intestines
spinal cord sympathetic activity)
parasympathetic – rest (contracts pupil-slow
heartbeat-dilates vessels-stimulates intestines
parasympathetic activity)
, Studying the brain
19th century ® phrenology (bump on head)
Currently used methods:
o Clinical observation of patients with brain damage (ex. Gage ® prefrontal cortex)
o Experimental techniques
• Invasive: animal studies (Hubel – Wiesel) – single cell recordings, lesions, optogenetics
• TMS (Transcranial Magnetic Stimulation) – studies active brain regions
o Other techniques
• Electrophysiology – an electroencephalograph (EEG) measures electrical activity in the brain.
• Brain imaging – correlational/observational methods
o Positron Emission Tomography (PET) – finds the most active brain areas
o Magnetic Resonance Imaging (MRI) – momentarily disrupts the brains magnetic forces, used
to provide information about the structure of the brain.
o Function Magnetic Resonance Imaging (fMRI) – maps the working brain
Distinguishing different parts of the brain
★ Brainstem – midbrain + pons + medulla; breathing, heartrate, swallowing
★ Cerebellum – balance, coordination, motor
★ Hypothalamus – body function
★ Amygdala – emotion
★ Basal ganglia – movement, reward
★ Thalamus – sensory gateway
★ Hippocampus – memory
★ Cerebral cortex
• Occipital lobe – vision
• Temporal lobe – audio, little bit vision, memory
• Parietal lobe – touch, spatial relations
• Frontal lobe – planning, thought
★ Corpus callosum – bridge of axons
50’s/60’s split brain patients, corpus callosum split
Some functions are lateralized, which makes it harder/impossible for split patients to accurately perform
these functions.
★ Lateralized – dominant in one hemisphere (ex. language in left hemisphere)
The size of a part of the cortex is in line with
the sensitivity of that part.
This image shows the homunculus of the
primary motor cortex in the left
hemisphere and the primary
somatosensory cortex in the right
hemisphere (note: information from the
right side of the body is processed in the
left hemisphere and vice versa). Note that
areas for, for example, lips and thumb are
much bigger than the one for your elbow,
because it’s way more sensitive
★ Plasticity – a property of the brain that allows it to change as result of injury/experience
decreases with age, because brain already “settles in” more
★ Neurogenesis – the production of new neurons. Still happens when you get older but just not as much
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