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Lecture 4

PSY100 Lecture 4 (September 20th, 2012).pdf

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Ashley W.Denton

Lecture 4 (September 20 , 2012) th Morad Moazami One  way  to  look  at  variability  is  to  look  at  the  range.     Another  way  is  through  a  measure  of  standard  deviation.  Standard  deviation  measures  how  far,   on  average,  each  sore  is  from  the  mean.  A  small  standard  deviation  means  that  your  data  is   clustered  around  the  mean,  while  a  larger  standard  deviation  says  that  your  scores  are  spread   out.     For  example,  if  the  class  average  on  a  test  is  75%,  and  you  got  85%  on  the  test.  You  did  better   than  the  average  student,  but  without  standard  deviation,  it  doesn't  say  when  you  fall  among   the  class.  Knowing  that  the  standard  deviation  is  5,  it  shows  that  most  of  the  scores  are  very   clustered.     If  the  mean  is  still  75,  but  the  distribution  has  changed,  then  the  standard  deviation  is  lager.  The   majority  of  scores  fall  between  60%  and  90%,  and  now  you’re  doing  better  than  average,  but   there  are  other  students  who  have  done  better  than  you.       So  standard  deviation  shows  whether  your  scores  are  close  to  each  other  or  more  scattered.     Correlations :     Scatterplots:  Graphs  that  illustrate  the  relationship  between  two  variables  (e.g.,  beer  sales  and   temperature).     If  there  is  no  correlation,  then  our  correlation  cooffiecient  is  zero,  which  means  that  two  things   have  no  relationship  between  them.  Positive  correlations  are  given  positive  numbers  up  to  the   number  1.0.  So  it’s  between  –  1  (a  perfect  negative  correlation  –  if  two  things  were  perfectly   correlated  with  one  another  but  as  one  increases  the  other  decreases)  and  +1  (so  perfect   positive  correlation:  as  one  increases  the  other  increases).     Evaluating  Our  Data:     Inferential  statistics:  A  set  of  procedures  used  to  make  judgments  about  whether  differences   actually  exist  between  sets  of  numbers.         We  want  to  be  able  to  make  claims  that  go  beyond  the  samples  of  data  that  we’ve  collected   and  go  beyond  the  population  we’re  interested  in.  Inferential  statistics  makes  claims  about   whether  scores  in  our  experimental  group  is  significantly  different  from  scores  in  our  controlled   group.     For  example,  for  a  Stroop  Test,  we  want  to  know  whether  the  observed  different  between  the   two  types  of  trials  is  statistically  significant  or  just  due  to  chance.  We  have  this  difference  of  .79   milliseconds  in  the  reaction  time  and  we  want  to  see  if  there’s  a  legitimate  difference.     Inferential  statistics  is  all  about  whether  the  results  we  get  is  due  to  chance  or  real  difference   from  what  we’re  drawing  our  data.     Replicate,  Revise,  Report     Replication:  May  be  an  exact  replication  (run  the  exact  same  study  again  to  see  whether  you   get  the  same  results)  or  a  conceptual  replication  (where  you  operationalize  your  variables  in  a   different  way),  for  example,  mood  manipulation.     In  conceptual  replication,  you're  not  running  the  exact  same  study,  but  you're  operationalizing   your  variables  in  a  different  way.     In  your  first  study  you  manipulate  the  mood  by  showing  one  half  of  your  audience  a  happy   movie  clip  before  they  learn  something  and  a  sad  one  for  another  group  to  find  out  that  people   in  better  moods  can  learn  better,  so  in  the  latter  experiment,  I  will  get  people  to  come  in  and   tell  me  about  their  happiest  memories  to  see  if  they  learn  the  thing  in  a  happy  mood,  so  you’re   operationalizing  mood  in  a  slightly  different  way.     What  if  our  study  doesn't  work  out?  If  your  hypothesis  was  not  supported  by  your  data,  think   about  what  this  means.  What  are  the  implications  for  the  theory  you  are  testing?  Should  you   revise  it?       The  report  side  of  things  is  very  important.  You  must  write  up  or  present  your  results  to  others.     The  Brain     Biological  Foundations:  Part  I     Genetics:     The  most  important  thing  out  of  this  chapter  is  that  nature  and  nurture  are  inextricably   entwined.  Nature  (genes)  and  nurture  (social  context)  interact  to  affect  human  behavior.     Today’s  Focus:     Neuron  structure  and  communication:  How  is  a  neuron  like  a  14-­‐year-­‐old  girl?     Brain  structures  and  their  functions:  How  does  synesthesia  happen?     The  Nervous  System:     The  nervous  system  is  the  body's  electrochemical  communication  circuitry.       It  is  estimated  that  the  human  brain  has  a  hundred  billion  neurons.  So  in  a  1  centimeter  cube  of   cheese,  there  are  50  million  nere  sells.     There  is  the  central  nervous  system  (CNS)  and  the  peripheral  nervous  system  (PNS).     The  peripheral  nervous  system  has  two  parts:   • Somatic  nervous  system:  outside   • Autonomic  nervous  system:  inside  (hey,  I’m  hungry).   o Sympathetic  nervous  system,   o Parasympathetic  nervous  system.     Neurons:     They  are  the  basic  unit  of  the  nervous  system.     They  differ  from  other  cells  in  the  terms  that  they  are  excitable,  and  they  communicate  with   other  neurons  through  chmical  signals.  They  operate  through  electrical  impulses.     There  are  three  types  of  neurons:   • Sensory  neurons  (afferent  neurons):  what  you  feel.   • Motor  neurons  (efferent  neurons):  motor  skills  like  moving  your  hands.   • Interneurons:  neurons  that  send  messages  between  sensory  neurons  and  motor   neurons.     A  good  hint  for  this  is:  SAME  (sensory,  afferent,  motor  efferent).     Just  like  people,  neurons  come  from  different  shapes  and  structures.  And  they  seem  to  have   the  same  nerve  structures.  The  first  part  of  the  neuron  is  the  dendrites  –  these  are  these   branch  like  extensions  that  receive  messages  from  the  cells  surrounding  it.  The  cell  body  takes   all  the  information  and  integrates  it  and  figures  out  what  to  do.  The  axon  is  this  long  narrow   structure  coming  of  the  neuron  and  it  is  key  to  the  electrical  impulse,  and  they  can  vary   dramatically.  Axons  are  the  ways  in  which  neurons  send  messages  to  one  another.  Then  at  the   end  of  the  axon  are  the  terminal  buttons,  who  release  the  chemicals.  Neurotransmitters  are  the   chemical  signals  that  get  sent  from  neurons  to  neurons.  The  receiving  neuron  picks  up  these   chemical  signals  and  decides  to  transfer  that  down  the  line.     How  is  a  neuron  like  a  14  year  old  girl?     She  is  getting  a  piece  of  gossip.  The  girl  is  a  receiving  neuron,  and  this  girl  has  to  see  if  she   should  get  this  gossip  and  tell  it  to  see  someone  –  it  depends  on  whether  she  gets  excited  or   not.     When  Do  Neurons  Fire?     Excitatory  signals:  these  increase  the  likelihood  that  the  neuron  will  fire.     Inhibitory  signals  decrease  the  likelihood  that  the  neurons  will  fire.     They  do  this  by  affecting  the  polarization  of  the  cell.     Neurons  fire  when  they  get  so  excited  that  they  cant  keep  it  in  longer  and  they  need  to  tell   someone  else.     All-­‐or-­‐none  principle:  A  neuron  fires  with  the  same  potency  each  time  (it  either  fires  or  does   not  fire);  but  how  frequently  the  neuron  fires  can  vary.  It  could  differ  in  the  frequency  by  which   it  fires.       Action  potential:  The  neural  impulse  that  passes  along  the  axon  and  subsequently  causes  the   release  of  chemicals  from  the  terminal  buttons.     Neurons  have  this  thrusting  memory  potential  and  they  are  polarized  –  their  electrical  charge  is   different  from  the  inside  than  the  outside.  This  thrusting  memory  potentially  shows  that  there's   potential  to  change.     Neurotransmitters:     How  neurons  send  information  from  one  neuron  to  another  is  through  neurotransmitters.     Neurotransmitters  are  chemical  substances  that  carry  signals  from  one  neuron  to  another.  They   are  stored  in  vesicles  (small  packages)  inside  the  terminal  buttons.  A  neurotransmitter   combined  only  with  its  particular  kind  of  receptor  could  be  transmitted.     Action  potentials  carry  the  vesicles  (small  packages  that  hold  these  different  substances),  and   when  they  reach  the  end  of  the  neuron,  they  release  these  chemicals  into  the  synapse.     There  is  a  whole  host  of  different  types  of  neurotransmitters.  The  most  common  ones  are:   • Acetylcholine:  responsible  for  the  motor  control  and  the  junction  between  nerves   and  muscles.  What  Botox  does  is  that  it  stops  acetylcholine  from  working.  It   paralyzes  the  muscles.   • Epinephrine:  Better  known  as  adrenaline.  Think  of  Pulp  Fiction’s  scene  with  Uma   Thurman’s  overdose.   • Norepinephrine   • Serotonin   • Dopamine:  very  important  for  the  reward  system  of  the  brain.  Dopamine  makes   what  you  think  is  rewarding  such  a  pleasurable  experience.   • GABA:   • Etc.:     How  Drugs  Work:     They  affect  how  neurotransmitters  work.     Agonists  enhance  a  neurotransmitters’  actions  by:   • Increasing  the  release  of  neurotransmitters,   • Blocking  the  re-­‐uptake  of  neurotransmitters   • Mimicking  a  neurotransmitter  (and  activating  a  postsynaptic  receptor).  Putting  on  a   costume,  pretending  to  be  a  neurotransmitter,  and  it  lets  it  in  and  it  activates  the   synapses  by  mimicking  a  neurotransmitter.   • Drugs  that  are  agonists  are  cocaine  and  methamphetamine.  They  work  by  increasing   the  release  of  dopamine.  That’s  why  these  drugs  are  so  rewarding  and  addictive,   because  they  activate  these  dopamine  receptors.     Antagonists  work  in  a  different  way.  They  inhibit  neurotransmitter's  actions  by:   • Blocking  the  release  of
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