Psychology Class Notes - The Brain

Psychology as a Science
 Histogram
o Distribution/spread of data
o For our class histogram, mean is 85
 Mode = 95
 Not normally distributed (skewed left)
 Higher = more agreeable that psych is a science
o Significance
 P-value
 How likely is it that the data are like this by chance?
 P, in %, is the % chance that the means would differ just by chance
 Significant if p<0.05
 What is a science?
o Must generate a falsifiable hypothesis
 Use systematic observations to test
 Reject hypotheses when observations consistently fail to support
 Only tentatively accept hypothesis after rigorous testing
 Never use “proven”
o Quantitative data
 Types of Psychological Study
o Case Study
 In depth study of one example
 Typically just one person
 Applied to the whole world/a society
o Naturalistic Observation
 Observing behavior as it naturally occurs
 No intervention
o Survey
 Asking people to self-report
o Correlation
 If two variables are associated
 Measurable variables
 Correlation coefficient shows how associated the variables are
 Often shown by a scatterplot
 Correlation  causation
 Could be another variable unaccounted for
o Experiment
 Manipulation
 Independent and dependent variable
 Can show causation


Biology of the Mind

,  Neurons
o Brain cells
o ~80 billion in the brain
o ~1000 synapses per neuron
 ~80 trillion synapses in the brain
o Structure
 Cell body
 Axon
 Sends messages/action potentials
 Dendrite
 Receives messages
o Communication
 Electrochemically
 Action potential
 Electrical impulse that travels down axon
 Prompts neurotransmitter release
 Neurons come close but do not touch
 Synaptic gap crossed chemically by neurotransmitter
 -70mV electronegativity
 Permeable membrane
 Ion channels open to allow cations in
 -55mV or higher causes the action potential
o Depolarization from -70mV to -55mV
o Releases neurotransmitter
 Release of neurotransmitter
 Pre-synaptic cells send
 Post-synaptic cells receive
o Adds all of its inputs together to decide whether to fire an
action potential
 Excitatory = positive
o Excited means closer to firing an action potential
 Inhibitory = negative
o Inhibited means farther from firing an action potential
 Brain Regions
o Brainstem
 Where spinal cord swells at the skull (medulla)
 Controls heartbeat and breathing
o Thalamus
 Attached to top of brainstem
 Sensory control center
o Reticular formation
 Inside brainstem, between ears
o Cerebellum