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PSY 2012 Chapter 4 Outline

by: Amanda Martinez

PSY 2012 Chapter 4 Outline PSY 2012

Marketplace > University of Florida > Psychlogy > PSY 2012 > PSY 2012 Chapter 4 Outline
Amanda Martinez
GPA 3.78

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Outline for Chapter 4 of Psychology: From Inquiry to Understanding 3rd Edition
General Psychology
Class Notes
PSY 2012, General Psycholoy, UF, chapter 4
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This 34 page Class Notes was uploaded by Amanda Martinez on Friday February 5, 2016. The Class Notes belongs to PSY 2012 at University of Florida taught by in Fall 2015. Since its upload, it has received 37 views. For similar materials see General Psychology in Psychlogy at University of Florida.


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Date Created: 02/05/16
Chapter  4:  Sensation  and  Perception   •   Illusion-­‐  perception  in  which  the  way  we  perceive  a  stimulus  doesn’t  match  its  physical   reality   •   Sensation-­‐  detection  of  physical  energy  by  sense  organs,  which  then  send  info  to  the   brain   o   Sensation  first  allows  us  to  pick  up  the  signals  in  our  environments   •   Perception-­‐  the  brain’s  interpretation  of  raw  sensory  inputs   o   Perception  allows  us  to  assemble  these  signals  into  something  meaningful   •   Naïve  realism-­‐  Often  assume  that  our  sensory  systems  are  infallible  and  that  our   perceptions  are  perfect  representations  of  the  world  around  us   o   Naive  realism  is  wrong   o   World  isn’t  as  we  see  it   •   Filling-­‐in-­‐  reconstructing  a  missing  part  and  putting  it  in  the  empty  space   o   Occurs  without  our  awareness   o   Adaptive   o   Helps  us  make  sense  of  our  often  confusing  and  chaotic  perceptual  worlds   o   Can  fool  us   •   We  often  blend  real  with  the  imagined   •   We  simplify  our  world  to  make  better  sense  of  it  in  the  process   Two  Sides  of  the  Coin:  Sensation  and  Perception   •   Our  brain  picks  and  chooses  among  the  types  of  sensory  info  it  uses   o   Relies  on  expectations  and  prior  experiences  to  fill  in  the  gaps  and  simplify   processing   Sensation:  Our  Senses  as  Detectives   •   Sense  enables  us  to  see  majestic  scenery,  hear  music,  feel  touch,  maintain  balance  as   we  walk  and  taste  food   •   All  of  our  senses  rely  on  a  mere  handful  of  basic  principles   •   Transduction-­‐  the  process  of  converting  an  external  energy  or  substance  into  electrical   activity  within  neurons   o   First  step   o   Converting  external  energies  into  a  “language”  the  nervous  system  understands   o   Sense  receptor-­‐  specialized  cell  responsible  for  converting  external  stimuli  into   neural  activity  for  a  specific  sensory  system   §   Specialized  cells  at  the  back  of  the  eye  transduce  light   §   Cells  in  a  spiral-­‐shaped  organ  in  the  ear  transduce  sound   §   Odd-­‐looking  endings  attached  to  axons  embedded  in  deep  layers  of  the   skin  transduce  pressure   §   Receptor  cells  lining  the  inside  of  the  nose  transduce  airborne  odorants   §   Taste  buds  transduce  chemicals  containing  flavor   •   Sensory  adaptation-­‐  activation  is  greatest  when  we  first  detect  a  stimulus   o   Adaptation  takes  place  at  the  level  of  the  sense  receptor   o   Strongly  at  first  then  dies  down  to  conserve  energy  and  additional  resources   •   Psychophysics-­‐  the  study  of  how  we  perceive  sensory  stimuli  based  on  their  physical   characteristics   •   Absolute  threshold-­‐  lowest  level  of  a  stimulus  needed  for  the  nervous  system  to  detect   a  change  50%  of  the  time   o   Demonstrate  how  remarkably  sensitive  our  sensory  systems  are   §   Visual  systems  can  detect  a  single  candle  from  30  miles  away   §   Smell  from  as  few  as  50  airborne  odorant  molecules   •   Just  noticeable  difference  (JND)-­‐  the  smallest  change  in  the  intensity  of  a  stimulus  that   we  can  detect   o   Relevant  to  our  ability  to  distinguish  a  stronger  from  a  weaker  stimulus   •   Weber’s  law-­‐  there  is  a  constant  proportional  relationship  between  the  JND  and  original   stimulus  intensity   o   The  stronger  the  stimulus,  the  bigger  the  change  needed  for  a  change  in  stimulus   intensity  to  be  noticeable   •   Signal  detection  theory-­‐  theory  regarding  how  stimuli  are  detected  under  different   conditions   o   Trying  to  figure  out  what  a  friend  is  saying  on  a  cell  phone  when  there’s  a  lot  of   static  in  the  connection   §   High  background  noise   §   Need  to  increase  signal  by  shouting  over  the  static  so  they  can  hear  us   o   Signal-­‐to-­‐noise  ratio-­‐  harder  to  detect  a  signal  as  background  noise  increases   o   Response  biases-­‐  tendencies  to  make  one  type  of  guess  over  another  when   we’re  in  doubt  about  whether  a  weak  signal  is  present  or  absent  under  noisy   conditions   §   Developed  a  clever  way  to  take  into  account  some  people’s  tendency  to   say  “yes”  when  they’re  uncertain  and  other  people’s  tendency  to  say   “no”   §   Sometimes  they  presented  a  sound,  sometimes  not   •   True  positive-­‐  hit;  hearing  a  sound  when  it  was  present   •   False  negative-­‐  miss;  denying  hearing  a  sound  when  it  was  present   •   False  positive-­‐  false  alarm;  hearing  a  sound  that  wasn’t  there   •   True  negative-­‐  true  negative;  deny  hearing  a  sound  that  wasn’t   there   •   Specific  nerve  energies-­‐  even  though  there  are  many  stimulus  energies,  the  sensation   we  experience  is  determined  by  the  nature  of  the  sense  receptor,  not  the  stimulus   o   Sensation  of  light  when  we  rub  our  eyes   o   Doesn’t  matter  if  light  or  touch  activated  the  sense  receptor   o   Our  brains  reacted  the  same  way   o   Stimulus  is  touch  (rubbing  our  eyes)  but  we’re  putting  pressure  on  the  eye’s   receptor   •   Scientists  have  found  many  examples  of  cross  modal  processing  that  produce  different   perceptual  experiences  than  either  modality  provides  itself   o   McGurk  effect-­‐  we  integrate  visual  and  auditory  info  when  processing  spoken   language,  and  our  brains  automatically  calculate  the  most  probable  sound  given   the  info  from  the  2  sources   §   Hearing  audio  track  of  one  syllable  (ba)   §   Seeing  a  video  of  a  different  syllable  being  spoken  (ga)   §   Produces  perceptual  experience  of  a  different  third  sound  (da)   §   Brain’s  best  guess  at  integrating  the  2  conflicting  sources  of  info   o   Illusion  that  shows  how  our  senses  of  touch  and  sight  interact  to  create  false   perceptual  experience   §   Placing  a  rubber  hand  on  a  table  with  the  precise  positioning  of  a   participant’s  hand  if  they  were  to  have  it  one  the  table   §   Researcher  simultaneously  strokes  participants  hidden  hand  and  the   rubber  hand  gently     §   Participant  feels  like  the  rubber  hand  becomes  their  own  hand   •   Cross-­‐modal  effects  may  reflect  “cross-­‐talk”  among  different  brain  regions   •   Single  brain  region  may  serve  double  duty  helping  to  process  multiple  senses   •   Synthesia-­‐  a  condition  in  which  people  experience  cross-­‐modal  sensations   o   Hearing  sounds  when  they  see  colors   o   Tasting  or  smelling  colors   The  Role  of  Attention   •   Flexible  attention  is  critical  to  our  survival  and  well-­‐being   •   Selective  attention-­‐  process  of  selecting  one  sensory  channel  and  ignoring  or  minimizing   others   o   Filter  theory  of  attention-­‐  allows  us  to  pay  attention  to  important  stimuli  and   ignore  others   o   Dichotic  listening-­‐  hearing  2  different  messages     §   Ignored  messages  sent  to  1  ear   §   Seemed  to  know  little  or  nothing  about  these  messages   §   Could  repeat  message  they  attended   •   Sometimes  mixed  some  info  they  were  supposed  to  ignore   §   The  info  we’ve  supposedly  filtered  out  of  our  attention  is  still  being   processed  at  some  level  we’re  not  aware  of   o   Cocktail  party  effect-­‐  ability  to  pick  out  an  important  message,  like  our  name,  in   a  convo  that  doesn’t  involve  us   o   Filter  in  our  brain  is  more  complex  than  just  an  “on”  and  “off”  switch   •   Inattentional  blindness-­‐  failure  to  detect  stimuli  that  are  in  plain  sight  when  our   attention  is  focused  elsewhere   •   Often  need  to  pay  close  attention  to  pick  out  even  dramatic  changes  in  our  environment   •   Change  blindness-­‐  failure  to  detect  changes  in  one’s  environment   The  Binding  Problem:  Putting  the  Pieces  Together   •   Binding  problem-­‐  brain  manages  to  combine  diverse  pieces  of  info  into  a  unified  whole   o   Don’t  know  how  we  do  it   o   Apple  looks  red,  feels  round/smooth,  tastes  sweet/tart,  smells  like  an  apple   o   Any  characteristic  in  isolation  isn’t  an  apple,  characteristics  together  make  it  an   apple   •   Rapid,  coordinated  activity  across  multiple  cortical  areas  assist  in  binding   o   May  explain  many  aspects  of  perception  and  attention   o   Rely  on  shape,  motion,  color  and  depth  cues  to  see  the  world   o   Mind  combines  everything  we  receive  from  different  senses  to  make  an  image  of   the  world  for  us   Seeing:  The  Visual  System   •   Building  up  an  image  involves  many  external  elements,  such  as  light,  biological  systems   in  the  eye  and  brain  that  process  images  for  us,  and  our  past  experiences   Light:  The  Energy  of  Life   •   Light  is  a  central  player  in  our  perception  of  the  world   o   A  form  of  electromagnetic  energy   o   Visible  light  has  wavelengths   o   We  only  respond  to  a  narrow  range  of  wavelengths  of  light   §   Human  visible  spectrum   •   When  light  reaches  an  object,  part  gets  reflected  and  part  gets  absorbed   •   Brightness-­‐  influenced  by  intensity  of  reflected  light  that  reaches  our  eyes   o   White-­‐  reflects  all  light  shone  on  it  and  absorbs  none;  presence  of  all  colors   o   Black-­‐  absorb  all  light  shone  on  it  and  reflect  none;  presence  of  no  colors   o   Brightness  also  depends  on  lighting  surrounding  object   •   Hue-­‐  color  of  light   •   Maximally  attuned  to  3  primary  colors:   o   Red,  green  and  blue   •   Additive  color  mixing-­‐  mixing  of  varying  amounts  of  these  3  colors  to  produce  any  color   •   Subtractive  color  mixing-­‐  mixing  of  colored  pigments  in  paint  or  ink   The  Eye:  How  We  Represent  the  Visual  Realm   •   Structures  towards  the  front  of  the  eyeball  influence  how  much  light  enters  our  eye   o   Focus  the  incoming  light  rays  to  form  an  image  at  the  back  of  the  eye   •   Sclera-­‐  white  of  the  eye   •   Iris-­‐  colored  part  of  the  eye   o   Usually  blue,  brown,  green  or  hazel   o   Controls  how  much  light  enters  our  eyes  by  expanding  and  contracting   •   Pupil-­‐  circular  hole  through  which  light  enters  the  eye   o   Closing  is  a  reflex  response  to  light  or  objects  coming  towards  us   §   Occurs  in  both  eyes  simultaneously   o   Dilation-­‐  expansion  of  the  pupil   §   Dilate  when  we’re  trying  to  process  complex  info,  when  we  view   someone  attractive  and  reflect  sexual  interest   •   Cornea-­‐  part  of  the  eye  containing  transparent  cells  that  focus  light  on  the  retina   o   Curved  layer  covering  the  iris  and  pupil   o   Bends  incoming  light  to  focus  the  incoming  visual  image  at  the  back  of  the  eye   •   Lens-­‐  part  of  the  eye  that  changes  curvature  to  keep  images  in  focus   o   Also  bends  light   o   Allows  us  to  fine-­‐tune  visual  images   o   Consists  of  some  of  the  most  unusual  cells  in  the  body   §   Completely  transparent,  allowing  light  to  pass  through  them   o   Accommodation-­‐  changing  the  shape  of  the  lens  to  focus  on  objects  near  or  far   §   Changes  shape  to  focus  light  on  the  back  of  the  eyes   §   Adapt  to  different  perceived  distances  of  objects   §   Flat-­‐  lens  becomes  long  and  skinny,  allowing  us  to  see  distant  objects   §   Fat-­‐  lens  becomes  short  and  wide,  allowing  us  to  focus  on  nearby  objects   •   How  much  our  eyes  need  to  bend  the  path  of  light  to  focus  depends  on  the  curve  of  our   corneas  and  overall  shape  of  our  eyes   •   Myopia-­‐  nearsightedness   o   Images  are  focused  in  front  of  the  rear  of  the  eye   o   See  close  objects  well;  can’t  see  far  objects   •   Hyperopia-­‐  farsightedness   o   Cornea  is  too  flat  or  our  eyes  are  too  short   o   See  far  objects  well;  inability  to  see  close  objects   •   Vision  worsens  with  age   o   Eyes  lose  flexibility  due  to  aging   •   Retina-­‐  membrane  at  the  back  of  the  eye  responsible  for  converting  light  into  neural   activity   o   Many  scholars  believe  it  is  technically  part  of  the  brain   o   Can  think  of  retina  as  a  movie  screen  where  light  from  the  world  is  projected   •   Fovea-­‐  central  portion  of  the  retina   o   Responsible  for  acuity-­‐  sharpness  of  vision   •   Rods-­‐  receptor  cells  in  the  retina  allowing  us  to  see  in  low  levels  of  light   o   More  plentiful   o   Long  and  narrow   o   Enable  us  to  see  basic  shapes  and  forms   o   Dark  adaptation-­‐  time  in  dark  before  rods  regain  maximum  light  sensitivity   §   Rods-­‐  going  from  light  to  dark   •   Cones-­‐  receptor  cells  in  the  retina  allowing  us  to  see  in  color   o   Shaped  like  small  cones   o   Sensitive  to  detail   o   Require  more  light   o   Activate  when  moving  from  dark  to  light   •   Photopigments-­‐  chemicals  that  change  following  exposure  to  light   o   Rods-­‐  rhodopsin   •   Ganglion  cells-­‐  cells  in  the  retinal  circuit  that  contain  axons,  bundle  all  their  axons   together  and  depart  the  eye  to  reach  the  brain   •   Optic  nerve-­‐  nerve  that  travels  from  the  retina  to  the  brain   o   Contains  the  axons  of  the  ganglion  cells   o   Comes  to  a  fork  called  the  optic  chiasm   §   Half  of  the  axons  cross  the  chiasm  and  the  other  half  stay  on  the  same   side   o   Optic  nerves  enter  the  brain,  turning  into  optic  tracts   §   Send  most  of  their  axons  to  the  visual  part  of  the  thalamus  and  the   primary  visual  cortex   §   Remaining  axons  go  to  midbrain,  specifically  superior  colliculus   •   Play  key  role  in  reflexes   o   Blind  spot-­‐  part  of  the  visual  field  we  can’t  see  because  of  an  absence  of  rods   and  cones   §   Axons  of  ganglion  cells  push  everything  else  aside   §   Experience  it  every  moment  of  our  lives     §   Brain  fills  in  gaps  created  by  the  blind  spot     •   Many  cells  in  the  primary  visual  cortex  (V1)  respond  to  slits  of  light  of  a  specific   orientation   o   Vertical,  horizontal,  oblique  lines  or  edges   •   Simple  cells-­‐  cells  in  the  visual  cortex  that  display  “yes-­‐no”  responses  to  slits  of  a  specific   orientation   o   Slits  need  to  be  in  a  specific  location   •   Complex  cells-­‐  orientation-­‐specific,  but  their  responses  are  less  restricted  to  one   location   o   Much  more  advanced  than  simple  cells   •   Feature  detection-­‐  ability  to  use  certain  minimal  patterns  to  identify  objects   •   Feature  detector  cells-­‐  cell  that  detects  lines  and  edges   •   Visual  info  travels  from  V1  to  higher  visual  areas   o   Association  cortexes  (V2)   o   One  travels  up  to  upper  parietal   o   Other  travels  down  to  temporal  lobe   •   Higher  cortical  regions  process  more  and  more  complex  shapes   •   Use  lower  visual  pathway  leading  to  temporal  lobe  to  process  color   •   Trichromatic  theory-­‐  idea  that  color  vision  is  based  on  our  sensitivity  to  3  primary  colors   o   3  kinds  of  cones   §   Each  is  sensitive  to  different  wavelengths,  therefore  each  detects  a   different  color   o   Examined  colors  color  blind  individuals  could  see  to  determine  3  primary  colors   o   Color  blindness-­‐  inability  to  see  some  or  all  colors   §   Absence  or  reduced  #  of  one  or  more  types  of  cones  stemming  from   genetic  abnormalities  or  damage  to  a  brain  area   §   Monochromats-­‐  only  have  1  type  of  cone  and  lose  all  color  vision   §   Dichromats-­‐  have  2  cones  and  are  missing  only  1   •   Red-­‐green  dichromats-­‐  can  see  all  colors  but  can’t  distinguish  reds   well   §   Trichromats-­‐  possess  3  different  types  of  cones   •   Afterimages-­‐  occur  when  we’ve  stared  at  one  color  for  a  long  time  and  then  look  away   o   Often  see  a  different  colored  replica  of  the  same  image   o   Arise  from  visual  cortex’s  processing  of  info  from  our  rods  and  cones   o   Opponent  process  theory-­‐  theory  that  we  perceive  colors  in  terms  of  3  pairs  of   opponent  colors;  either  red  or  green,  blue  or  yellow,  black  or  white   o   Afterimages  appear  in  complementary  colors   •   Nervous  system  uses  trichromatic  and  opponent  processing  during  color  vision   o   Different  neurons  rely  on  one  principle  more  than  the  other   When  We  Can’t  See  or  Perceive  Visually   •   Blindness-­‐  inability  to  see   •   Majority  of  cases  from  cataracts  and  glaucoma  are  treatable   •   Blind  rely  more  on  other  senses   o   Especially  touch   o   Can  devote  somatosensory  and  visual  cortexes  to  touch  senses   §   Illustrates  brain  plasticity   •   Blindsight-­‐  ability  of  blind  people  with  damage  to  their  cortex  to  make  correct  guesses   about  the  appearance  of  things  around  them   o   Some  people  believe  it  to  be  ESP   •   Echolocation-­‐  emitting  sounds  and  listening  to  their  echoes  to  determine  their  distance   from  a  wall  or  barrier   o   Same  parts  of  the  brain  associated  with  visual  images  in  sighted  people  become   highly  active   •   Visual  agnosia-­‐  deficit  in  perceiving  objects   o   Can  tell  the  shape  and  color  of  an  object,  but  can’t  recognize  or  name  it   Hearing:  The  Auditory  System   •   Audition-­‐  our  sense  of  hearing   •   Probably  the  sensory  modality  we  rely  on  most  to  acquire  info  about  our  world   Sound:  Mechanical  Vibration   •   Sound  is  vibration-­‐  mechanical  energy  traveling  through  a  medium,  usually  air   •   Disturbance  created  by  vibration  of  molecules  of  air  produces  sound  waves   o   Can  travel  through  any  gas,  liquid  or  solid,  but  we  hear  them  best  when  they   travel  through  air   o   Can’t  be  sound  in  a  vacuum   •   Pitch-­‐  corresponds  with  the  frequency  of  the  waves   o   Higher  frequency-­‐  higher  pitch   o   Lower  frequency-­‐  lower  pitch   o   Frequency  is  measured  in  Hertz  (Hz)   •   Loudness-­‐  amplitude,  or  height,  of  the  sound  wave  corresponds  to  loudness   o   Measured  in  decibels  (dB)   o   Loud-­‐  more  mechanical  disturbance  (more  vibrating)  of  airborne  molecules   •   Timbre-­‐  complexity  or  quality  of  sound  that  makes  musical  instruments,  human  voices   or  other  sources  sound  unique   Structure  and  Function  of  the  Ear   •   3  parts:  outer,  middle  and  inner   •   Outer  ear-­‐   o   Pinna-­‐  part  of  the  ear  we  see   o   Ear  canal-­‐  funnels  sounds  to  the  ear  drum   •   Middle  ear-­‐   o   Ossicles-­‐  3  tiniest  bones  in  the  body   §   Hammer,  anvil  and  stirrup   §   Vibrate  at  the  frequency  of  the  sound  wave  transmitting  it  from  the   eardrum  to  the  inner  ear   •   Inner  ear-­‐   o   Cochlea-­‐  bony,  spiral-­‐shaped  sense  organ  used  for  hearing   §   Converts  vibration  into  neural  activity   §   Outer  part  is  bony,  inner  cavity  is  filled  with  a  thick  fluid   §   Vibrations  disturb  this  fluid  and  travel  to  the  base  of  the  cochlea,  where   pressure  is  released  and  transduction  occurs   o   Organ  of  Corti-­‐  tissue  containing  the  hair  cells  necessary  for  hearing   o   Basilar  membrane-­‐  membrane  supporting  the  organ  of  Corti  and  hair  cells  in  the   cochlea   §   Hair  cells-­‐  where  transduction  of  auditory  info  takes  place   •   Converts  acoustic  info  into  action  potentials   •   Auditory  perception  becomes  increasingly  complex  like  visual  perception   •   Primary  auditory  cortex  processes  different  tones  in  different  places   o   Each  place  receives  info  from  a  specific  place  in  the  basilar  membrane   o   Hair  cells  located  at  the  base  of  the  basilar  membrane  are  most  excited  by  high   pitched  tones   o   Hairs  at  the  top  are  excited  by  low  pitched  tones   o   Place  theory-­‐  specific  place  along  the  basilar  membrane  matches  a  tone  with  a   specific  pitch   •   Frequency  theory-­‐  rate  at  which  neurons  fire  the  action  potential  reproduces  the  pitch   o   Volley  theory-­‐  works  for  tones  between  100-­‐5000  Hz,  sets  of  neurons  fire  at  their   highest  rate  slightly  out  of  sync  to  reach  overall  rates  up  to  5000  Hz   When  We  Can’t  Hear   •   1/1000  people  are  deaf   •   Deafness  is  caused  by  genetics,  disease,  injury  or  exposure  to  loud  noises   •   Conductive  deafness-­‐  due  to  malfunctioning  of  the  ear   o   Especially  a  failure  of  the  eardrum  or  the  ossicles   •   Nerve  deafness-­‐  damage  to  the  auditory  nerve   •   Loud  sounds  can  damage  our  hair  cells  and  lead  to  noise  induced  hearing  loss   o   Accompanied  by  tinnitus-­‐  ringing,  roaring,  hissing  or  buzzing  sound  in  the  ear   •   Hearing  loss  can  also  result  to  hearing  one  loud  sound  i.e.  an  explosion   •   Most  lose  hearing  ability  as  we  age   Smell  and  Taste:  The  Sensual  Senses   •   Olfaction-­‐  sense  of  smell   •   Gustation-­‐  sense  of  taste   o   Work  hand  in  hand  enhancing  our  linking  of  some  foods  and  disliking  of  others   •   Chemical  senses  because  we  derive  the  sensory  experiences  from  chemicals  in   substances   •   Most  critical  function  of  chemical  senses  is  to  sample  food  before  we  swallow  it   What  are  Odors  and  Flavors?   •   Odors-­‐  airborne  chemicals  that  interact  with  receptors  in  the  lining  of  our  nasal   passages   •   Noses  are  veritable  smell  connoisseurs   o   Capable  of  detecting  between  2,000-­‐4,000  different  odors   •   Can  detect  only  few  tastes     o   Sensitive  to  5  basic  tastes:  sweet,  salty,  sour,  bitter  and  umami  (meaty/savory)   o   Preliminary  evidence  for  a  sixth  taste  for  fat   Sense  Receptors  for  Smell  and  Taste   •   Humans  have  1000+  olfactory  genes   •   Each  olfactory  neuron  contains  a  single  type  of  olfactory  receptor  that  recognizes  and   odorant     o   Lock  and  key  concept   •   When  olfactory  receptors  come  in  contact  with  odor  molecules,  action  potentials  in   olfactory  neurons  are  triggered   •   Detect  taste  with  taste  buds-­‐  sense  receptor  in  the  tongue  that  responds  to  sweet,  salty,   sour,  bitter,  umami  and  perhaps  fat   o   Papillae-­‐  bumps  on  tongue  that  contain  numerous  taste  buds   o   Separate  taste  buds  for  sweet,  salty,  sour,  bitter  and  umami   •   Myth  that  “tongue  taste  map”  describes  a  tongue’s  sensitivity  to  different  flavors   o   Weak  tendency  for  individual  taste  receptors  to  concentrate  in  certain  locations   •   Taste  is  biased  strongly  by  our  sense  of  smell   o   We  find  certain  foods  “delicious”  because  of  their  smell   •   Supertasters-­‐  people  with  a  marked  overabundance  of  taste  buds   o   About  25%  of  people   Olfactory  and  Gustatory  Perception   •   Perception  of  smell  and  taste  are  sensitive   •   After  odors  interact  with  the  sense  receptors  in  the  nasal  passages,  info  enters  the   brain,  reaching  the  olfactory  cortex  and  parts  of  the  limbic  system   •   After  taste  info  interacts  with  taste  buds,  it  enters  brain,  reaching  the  gustatory  cortex,   somatosensory  cortex  and  parts  of  the  limbic  system   •   Region  of  frontal  cortex  is  a  site  of  convergence  for  smell  and  taste   •   Analyze  the  intensity  of  a  smell  and  determine  whether  it’s  pleasing   o   Amygdala  help  us  distinguish  pleasant  from  disgusting  smells   •   Taste  can  also  be  pleasant  or  disgusting   o   Tasting  disgusting  food  and  seeing  faces  of  disgust  activate  gustatory  cortex   o   Persons  who  experience  damage  to  gustatory  cortex  don’t  experience  disgust   •   Emotional  disorders  can  distort  taste  perception   o   Serotonin  and  norepinephrine  make  us  more  sensitive  to  taste   o   Antidepressants  enhance  tastes   •   Smells  play  a  strong  role  in  sexual  behavior   o   Especially  in  animals   o   Mice  that  can’t  smell  don’t  bother  to  mate   o   Pheromones-­‐  odorless  chemical  that  serves  as  a  social  signal  to  members  of   one’s  species   §   Alter  our  sexual  behaviors   o   Vomeronasal  organ-­‐  located  in  the  bone  between  the  nose  and  the  mouth,  to   detect  pheromones   §   Doesn’t  develop  in  humans   §   Causes  some  to  suggest  humans  are  insensitive  to  pheromones   o   Nerve  zero-­‐  enable  pheromones  to  trigger  responses  in  the  “hot-­‐button  sex   regions  of  the  brain”   When  We  Can’t  Smell  or  Taste   •   2  million  Americans  suffer  from  a  disorder  of  taste,  smell  or  both   •   Gradual  loss  of  taste  and  smell  can  be  part  of  normal  aging   •   Losses  can  also  result  from  disease,  such  as  diabetes  and  high  blood  pressure   •   Damage  to  olfactory  nerve  can  damage  our  sense  of  smell  and  ability  to  identify  odors   •   Losing  our  sense  of  taste  can  also  produce  negative  health  consequence   Our  Body  Senses:  Touch,  Body  Position  and  Balance   •   Somatosensory-­‐  sense  of  touch,  temperature  and  pain   •   Proprioception-­‐  kinesthetic  sense,  body  position  sense   •   Vestibular  sense-­‐  sense  of  equilibrium  or  balance   The  Somatosensory  System:  Touch  and  Pain   •   Responds  to  stimuli  applied  to  the  skin   o   Light  touch  or  deep  pressure   o   Hot/cold  temp   o   Chemical  or  mechanical  injury  that  produces  pain   •   Stimuli  can  be  very  specific   o   Braille   •   Damage  to  internal  organs  sometimes  causes  “referred  pain”-­‐  pain  in  a  different   location   o   Pain  in  left  arm  during  a  heart  attack   •   Sense  touch  with  specialized  nerve  endings  located  on  the  ends  of  sensory  nerves  in  the   skin   •   Free  nerve  endings-­‐  more  plentiful  than  specialized  nerve  endings   o   Sense  touch,  temperature  and  especially  pain   •   Nerve  endings  are  distributed  evenly  across  the  body’s  surface   o   Most  are  in  our  fingertips   o   Then  lips,  face,  hands  and  feet   o   Have  the  fewest  in  our  middle  back   •   Info  about  touch,  temp  and  pain  travel  in  our  somatic  nerves  before  entering  the  spinal   cord   •   Touch  info  travels  more  quickly  than  pain  info   •   Touch  informs  us  of  our  immediate  surroundings  and  keys  us  into  urgent  matters   •   Pain  alerts  us  to  take  care  of  injuries,  can  often  wait  a  little  while   •   Touch  and  pain  info  activate  local  spinal  reflexes  before  reaching  the  brain   o   After  activating  spinal  reflexes,  touch  and  pain  travels  upward  through  parts  of   the  brain  stem  and  thalamus  to  reach  the  somatosensory  cortex   §   Additional  cortical  areas  active  for  touch  info  are  association  areas  of  the   parietal  lobe   •   Many  types  of  pain  perception  relate  to  the  pain-­‐causing  stimulus   o   Thermal,  chemical  or  mechanical   •   Threshold-­‐  point  at  which  we  perceive  it  as  painful   o   Each  type  of  pain-­‐producing  stimulus  has  a  threshold   •   Pain  has  an  emotional  component   o   Pain  info  goes  to  the  somatosensory  cortex  and  partly  to  limbic  centers  in  the   brain  stem  and  forebrain   o   Experience  of  pain  is  frequently  associated  with  anxiety,  uncertainty  and   helplessness   •   Scientists  believe  we  can  control  pain  through  our  thoughts  and  emotions   o   Gate  control  model-­‐  idea  that  pain  is  blocked  or  gated  from  consciousness  by   neural  mechanisms  in  spinal  cord   §   Functions  as  a  “gate”  controlling  the  flow  of  sensory  input  to  the  CNS   §   Account  for  how  pain  varies  from  situation  to  situation  depending  on  our   psychological  state   •   Become  so  absorbed  in  an  activity  that  we  forget  about  pain   §   The  stimulation  we  experience  competes  with  and  blocks  the  pain  from   consciousness   §   Pain  demands  attention   o   Brain  controls  activity  in  the  spinal  cord,  allowing  us  to  turn  up,  damp  down,  or   ignore  pain   o   Placebo  effect  exerts  strong  response  on  pain   §   Stimulate  the  body  to  produce  endorphins-­‐  natural  pain  killers   •   Phantom  limb-­‐  pain  or  discomfort  felt  in  an  amputated  limb   o   50-­‐80%  of  amputees  feel  phantom  limb  sensations   o   Missing  limb  feels  as  if  its  in  an  uncomfortably  distorted  position   o   Mirror  box-­‐  treatment  for  phantom  limb   §   Position  other  limb  so  it’s  reflected  in  the  position  the  amputated  limb   would  assume   §   Patient  performs  “mirror  equivalent”  of  the  exercise  the  amputated  limb   needs  to  relieve  a  cramp  or  get  comfortable   §   Illusion  must  be  realistic  in  order  to  relieve  pain/discomfort   •   Some  people  can’t  feel  pain   •   Pain  serves  an  essential  function   •   Pain  insensitivity-­‐  unable  to  detect  painful  stimuli   o   Inherited   o   Extremely  rare   o   Dangerous   •   Indifference  to  painful  stimuli-­‐  identify  the  type  of  pain,  but  experience  no  discomfort   from  it   Proprioception  and  Vestibular  Sense:  Body  Position  and  Balance   •   Proprioception-­‐  our  sense  of  body  position   o   Kinesthietic  sense   o   Helps  us  keep  track  of  where  we  are  and  move  efficiently   •   Vestibular  sense-­‐  sense  of  equilibrium  and  balance   o   Sense  of  equilibrium   o   Sense  and  maintain  our  balance  as  we  move  about   •   Sense  of  body  position  and  balance  work  together   •   Proprioceptors-­‐  sense  muscle  stretch  and  force   o   We  can  tell  what  our  bodies  are  doing,  even  with  our  eyes  closed   o   Stretch  receptors-­‐  embedded  in  our  muscles     o   Force  detectors-­‐  embedded  in  or  muscle  tendons   o   Info  enters  the  spinal  cord,  travels  up  the  brain  stem  to  the  thalamus  to  reach   the  somatosensory  and  motor  cortexes,  then  our  brains  combine  info  from  our   muscles  and  tendons  to  obtain  a  sense  of  our  body’s  location   •   Semicircular  canals-­‐  3  fluid  filled  canals  in  the  inner  ear  responsible  for  our  sense  of   balance   o   Located  in  inner  ear   o   Sense  equilibrium  and  help  us  maintain  our  balance   o   Reaches  parts  of  the  brain  stem  that  control  eye  muscles  and  triggers  reflexes   that  coordinate  eye  and  head  movements   o   Travels  to  the  cerebellum,  which  enables  us  to  catch  our  balance   o   Vestibular  sense-­‐  balancing   §   Not  heavily  represented  in  the  cerebral  cortex   §   Awareness  of  this  sense  is  limited   §   Become  aware  only  when  we  lose  our  balance  or  experience  dramatic   mismatches  between  vestibular  and  visual  imputs   Ergonomics:  Human  Engineering   •   Human  factors-­‐  optimizes  technology  to  better  suit  our  sensory  and  perceptual   capabilities   •   Ergonomic-­‐  worker-­‐friendly   •   We  use  our  knowledge  about  human  psychology  and  sensory  systems  to  build   ergonomic  tools  and  gadgets  of  trade   Perception:  When  Our  Senses  Meet  Our  Brains   •   Our  brain  pieces  together  what’s  in  our  sensory  field,  what  was  just  there  a  moment   ago,  what  we  remember  from  our  past   •   Sacrifice  small  details  in  favor  of  crisp  and  more  meaningful  representations   Parallel  Processing:  The  Way  Our  Brain  Multitasks   •   Parallel  processing-­‐  the  ability  to  attend  to  many  sense  modalities  simultaneously   o   Bottom-­‐  up  processing-­‐  processing  in  which  a  whole  in  constructed  from  parts   §   Perceiving  an  object  on  the  basis  of  its  edges   §   Starts  with  raw  stimuli  and  ends  with  synthesizing  them  into  a   meaningful  concept   §   Begins  with  activity  in  the  primary  visual  cortex,  followed  by  processing  in   the  association  cortex   o   Top-­‐down  processing-­‐  conceptually  driven  processing  influenced  by  beliefs  and   expectancies   §   Starts  with  our  beliefs  and  expectations,  which  we  then  impose  on  the   raw  stimuli  we  perceive   §   Starts  with  processing  in  association  cortex,  followed  by  processing  in  the   primary  cortex   o   Two  kinds  of  processing  work  together   Perceptual  Hypotheses:  Guessing  What’s  Out  There   •   We  try  to  get  by  with  as  little  neural  firepower  as  we  can   •   Perceptual  set-­‐  set  formed  when  expectations  influence  perceptions   o   Example  of  top-­‐down  processing   o   May  perceive  a  letter  as  an  “H”  or  an  “A”  depending  on  the  surrounding  letters   around  it   o   Tend  to  perceive  the  world  in  accord  with  our  preconceptions   •   Perceptual  consistency-­‐  process  by  which  we  perceive  stimuli  consistently  across  varied   conditions   o   Without  it  we’d  be  hopelessly  confused  because  we’d  be  seeing  the  world  as   continually  changing   o   Brain  allows  us  to  correct  from  these  minor  changes   o   Size  consistency-­‐  ability  to  perceive  objects  as  the  same  size  no  matter  how  far   they  are  from  us   §   Friend  walking  away  from  us-­‐  image  becomes  smaller   §   Brains  mentally  enlarge  figures  far  away  from  us  so  they  appear  more  like   similar  objects  in  the  same  scene   o   Shape  consistency-­‐  allows  us  to  recognize  a  stimulus  by  it’s  shape   §   We  can  recognize  a  door  whether  it’s  open,  barely  open,  or  closed   o   Color  consistency-­‐  ability  to  perceive  a  color  consistently  across  different  levels   of  lighting   §   Firefighter’s  jackets  look  yellow  even  in  low  lighting   §   Base  our  colors  on  the  surrounding  context   •   Subjective  contours-­‐  brain  providing  missing  info  about  outlines   •   Gestalt  principles-­‐rules  governing  how  we  perceive  objects  as  wholes  within  their   overall  context   o   Help  explain  why  we  see  much  of  our  world  consisting  of  unified  figures  or  forms   rather  than  confusing  jumbles  of  lines  and  curves   o   Provide  a  roadmap  for  how  we  make  sense  of  our  perceptual  world   o   Proximity-­‐  objects  physically  close  to  each  other  tend  to  be  perceived  as  unified   wholes   o   Similarity-­‐  we  see  objects  as  comprising  a  whole,  much  more  so  than  dissimilar   objects   §   Lining  up  red  and  yellow  dots-­‐  perceive  rows   o   Continuity-­‐  perceive  objects  as  wholes,  even  if  other  objects  block  them   o   Closure-­‐  when  partial  visual  info  is  present,  our  brain  fills  in  what’s  missing   o   Symmetry-­‐  perceive  objects  that  are  symmetrically  arranged  as  wholes  more   often  than  those  that  aren’t   o   Figure-­‐ground-­‐  make  an  instantaneous  decision  to  focus  attention  on  what  we   believe  to  be  the  central  figure  and  ignore  the  background   •   Bistable  image-­‐  an  image  we  can  perceive  in  2  ways   o   Vase  and  2  faces  looking  at  each  other   o   Emergence-­‐  perceptual  gestalt  that  almost  jumps  out  from  the  page  and  hits  us   all  at  once   •   We  perceive  motion  by  comparing  visual  frames   o   Like  film  in  a  movie  moving  at  rapid  motion  to  create  movement   •   Can  perceive  motion  when  it’s  not  there   •   Phi  phenomenon-­‐  illusory  perception  of  movement  produced  by  the  successive  flashing   of  images   o   Flashing  lights  that  circle  around  a  movie  marquee   •   Motion  blindness-­‐  disorder  where  patients  can’t  seamlessly  string  still  images  processed   by  their  brains  into  the  perception  of  ongoing  motion   o   “frames”  of  motion  are  missing   o   interferes  with  simple  tasks,  like  crossing  the  street   •   Depth  perception-­‐  ability  to  judge  distance  and  3-­‐D  relations   o   Enables  us  to  reach  for  a  glass  and  grasp  it  rather  than  knock  it  over   o   Need  to  have  some  idea  of  how  close  or  far  we  are  to  from  objects  to  navigate   around  our  environments   o   Monocular  depth  cues-­‐  stimuli  that  enable  us  to  judge  depth  using  only  1  eye   §   Relying  on  pictorial  cues  to  give  us  a  sense  of  what’s  located  where  in   stationary  scenes   •   Relative  size-­‐  more  distant  objects  look  smaller  than  closer  objects   •   Texture  gradient-­‐  texture  becomes  less  apparent  as  objects  move   away   •   Interposition-­‐  closer  object  blocks  our  view  of  an  object  behind  it   •   Linear  perspective-­‐  outlines  of  rooms  or  buildings  converge  as   distance  increases   •   Height  in  plane-­‐  distant  objects  tend  to  appear  higher,  nearer   objects  lower   •   Light  and  shadow-­‐  objects  cast  shadows  that  give  us  a  sense  of   their  3-­‐D  form   §   Motion  parallax-­‐  ability  to  judge  the  distance  of  moving  objects  from   their  speed   •   Nearby  objects  seem  to  move  faster  than  those  far  away   o   Binocular  depth  cues-­‐  stimuli  that  enable  us  to  judge  depth  using  both  eyes   §   Binocular  disparity-­‐  each  eye  sees  the  world  a  bit  differently     •   Left  and  right  eyes  transmit  quite  different  info  for  near  objects   •   See  distant  objects  similarly   •   Brains  use  info  to  judge  depth   §   Binocular  convergence-­‐  focusing  on  objects  reflexively  using  our  eye   muscles  to  turn  our  eyes   •   Our  brains  are  aware  of  how  much  our  eyes  are  converging  and   use  this  info  to  estimate  difference   •   We  can  judge  depth  as  soon  as  we  learn  to  crawl   o   Visual  cliff-­‐  a  table  and  floor  several  feet  below,  both  covered  by  ch


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