心理学与生活-第30节

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system　is　the　most　resistant　to　damage　of　all　sensory　systems；　as　taste　
receptors　are　replaced　every　few　days；　even　more　often　than　smell　
receptors　
C。　Touch　and　Skin　Senses　
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1。　Cutaneous　senses　are　sensations　produced　by　the　skin；　such　as　pressure；　
cold；　and　warmth。　Because　the　skin　responds　to　so　many　types　of　
stimuli；　many　different　types　of　receptors　are　located　near　the　surface　of　
the　skin。　
2。　Meissner　corpuscles　respond　best　when　something　rubs　against　the　skin　
3。　Merkel　disks　are　most　active　when　a　small　object　exerts　steady　pressure　
on　the　skin　
4。　The　skin　has　separate　receptors　for　hot　and　cold　
5。　Erogenous　zones　are　areas　of　the　skin　that　give　rise　to　erotic；　sexual　
sensations　
D。　The　Vestibular　and　Kinesthetic　Senses　
1。　Vestibular　sense　tells　how　the　body　is　oriented　in　the　world　with　respect　to　
gravity　through　tiny　hairs　in　fluid…filled　sacs　and　canals　in　the　inner　ear　
a）　The　saccule　and　utricle　detect　acceleration　and　deceleration　

b）　The　semicircular　canals　are　at　right　angles　to　each　other　and　can　
thus　detect　movement　in　any　direction　

c）　Motion　sickness　occurs　when　information　from　the　visual　system　
conflicts　with　information　from　the　vestibular　system　

2。　The　kinesthetic　sense　provides　constant　sensory　feedback　about　what　the　
body　is　doing　during　motor　activities。　There　are　two　sources　of　
kinesthetic　information：　receptors　in　the　joints　and　receptors　in　muscles　
and　tendons　
a）　Receptors　in　the　joints　respond　to　pressures　that　acpany　
different　positions　of　the　limbs　and　to　pressure　changes　that　
acpany　movements　

b）　Receptors　in　the　muscles　and　tendons　respond　to　changes　in　
tension　that　acpany　muscle　shortening　and　lengthening　

E。　Pain　
1。　Pain　is　the　body’s　response　to　noxious　stimuli　that　are　intense　enough　to　
cause　damage　or　threaten　to　do　so。　Pain　is　critical　to　survival。　People　
with　insensitivity　to　pain　often　bee　scarred　and　their　limbs　deformed　
from　injuries　that　could　have　been　prevented　had　they　been　sensitive　to　
pain。　
2。　Pain　mechanisms　
a）　Nociceptive　pain　is　the　negative　feeling　induced　by　a　noxious　
external　stimulus；　such　as　a　hot　stove　

b）　Neuropathic　pain　is　caused　by　the　abnormal　functioning　or　over　
activity　of　nerves　

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c）　The　network　of　pain　receptors　is　a　fine　mesh　that　covers　the　entire　
body。　Some　receptors　respond　only　to　temperature；　while　others　
respond　to　chemical　or　mechanical　stimuli。　

d）　Peripheral　nerve　fibers　transmit　signals　to　the　central　nervous　
system　in　two　ways：　

i）　Fast…conducting；　myelinated　nerves　

ii）　Slower；　smaller；　nonmyelinated　nerves　

e）　Pain　impulses　start　at　the　spinal　cord；　are　relayed　to　the　thalamus；　
and　then　to　the　cerebral　cortex　

3。　The　Psychology　of　Pain　
a）　Emotional　responses；　context　factors；　and　subjective　interpretation　
can　be　as　important　as　actual　physical　stimuli　in　determining　how　
much　pain　is　experienced　

b）　Phantom　limb　phenomenon　is　the　experience　of　sensation　or　pain　
in　a　limb　that　is　no　longer　there。　It　occurs　in　up　to　10　percent　of　
amputees。　

c）　Pain　is　partly　a　psychological　response　and；　thus；　can　be　
influenced　by　psychological　processes；　such　as　hypnosis；　deep　
relaxation；　and　thought　distraction。　The　Lamaze　preparation　for　
childbirth　is　an　excellent　example　of　the　psychological　control　of　
pain。　

d）　The　Gate…Control　Theory　of　pain；　proposed　by　Ronald　Melzack；　
suggests　that　cells　in　the　spinal　cord　act　as　neurological　gates；　
interrupting　and　blocking　some　pain　signals　and　letting　others　
through　to　the　brain。　The　brain　and　receptors　in　the　skin　send　
messages　to　the　spinal　cord　to　open　or　close　the　gates。　

e）　In　recent　years　Melzack　proposed　an　updated　neuromatrix　theory　
of　pain　which　incorporates　the　reality　that　people　often　experience　
pain　with　little　or　no　physical　cause。　

DISCUSSION　QUESTIONS　

1。　What　other　senses　might　there　be　that　humans　lack？　How　would　we　know　that　they　
existed？　How　might　humans　develop　devices；　such　as　binoculars；　night…vision　scopes；　and　
hearing　aids；　which　allow　us　to　experience　these　senses？　
2。　How　similar　are　sensory　experiences　between　people？　Do　all　individuals　experience　the　
color　“blue”　the　same？　How　would　we　know　if　we　did　not；　and　would　it　matter？　
3。　Have　the　class　think　of　real…life　examples　of　dichotic　listening。　Is　this　a　phenomenon　with　
which　they　are　familiar　and　of　which　they　have　a　basic　understanding？　
4。　Discuss　attention　from　the　perspectives　of　its　being　goal…directed　or　stimulus…driven　
perception。　Generally　speaking；　do　more　students　seem　to　be　goal…directed　attendees　or　
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stimulus…driven　perceivers？　What　might　contribute　to　this　phenomenon？　

5。　Discuss　the　premises　of　Gestalt　psychology　with　the　class。　Point　out　that　Kurt　Lewin’s　
Field　Theory　was　a　result　of　the　Gestalt　movement。　What　other　theoretical　constructions　
might　have　a　relationship　to　the　Gestalt　movement？　
6。　Discuss　the　wide　variance　that　exists　among　people　in　their　sensitivity　to　pain。　The　
sensation　of　pain　is　a　plex　process　involving　multiple　nerve　pathways。　But　to　some　
degree；　responses　to　pain　might　be　learned。　In　the　19th　century；　writers　often　noted　that　
Native　Americans　were　remarkably　stoic　in　the　face　of　what　Whites　considered　
overwhelming　pain。　Other　researchers　have　also　noted　cultural　differences　in　pain　
threshold。　While　individual　differences　can　easily　be　chalked　up　to　differences　in　biological　
makeup；　cultural　differences　are　more　difficult　to　pass　off　as　exclusively　biological　in　
origin。　
7。　Could　it　be　that　to　some　degree　we　learn　how　to　respond　to　pain　messages　based　on　factors　
such　as　how　much　attention　we　receive　for　crying　in　response　to　pain　when　we　are　infants？　
Many　parents　of　young　children　have　remarked　about　incidents　where　their　child　has　
fallen；　and　then　looked　up　at　the　parents　as　if　asking　“How　should　I　react？”　If　the　parents　
start　to　make　a　big　fuss　over　the　fall；　the　child　immediately　starts　to　cry。　If　the　parents　smile　
and　stay　calm；　the　child　ignores　the　fall　and　returns　to　playing。　If　a　parent　constantly　
overreacts　to　small　falls；　and　lavishes　attention　on　a　child　every　time　he　or　she　cries；　could　
they　be　reinforcing　a　tendency　to　react　negatively　to　any　pain　and　use　overblown　reactions　
to　pain　as　a　means　of　getting　attention？　Could　this　influence　those　children　to　be　more　
sensitive　to　any　painful　stimuli　in　that　they　learn　to　attend　more　to　pain　messages　and　
subsequently　notice　them　more？　Ask　students　these　questions　to　see　what　they　think。　
8。　Many　people　believe　the　myth　that　when　people　lose　one　of　their　physical　senses；　their　
other　senses　bee　more　sensitive　to　pensate　for　the　missing　sense。　The　idea　that　
blind　people　have　hearing　that　is　more　acute　than　others　has　been　around　for　ages。　Ask　
students　if　they　have　heard　this　and　if　they　believe　it。　This　myth　is　technically　wrong　in　that　
there　is　no　actual　increase　in　physical　ability　to　detect　sound　when　someone　goes　blind。　But　
blind　people　may　learn　to　pay　more　attention　to　subtle　differences　in　sound　than　do　sighted　
people；　therefore　making　it　seem　as　if　their　hearing　has　increased　in　its　sensitivity。　
Similarly；　losing　one’s　hearing　does　not　increase　one’s　visual　acuity；　but　deaf　people　often　
pay　more　attention　to　certain　visual　cues　than　do　those　who　can　hear；　allowing　them　to　
learn　more　from　those　cues。　
9。　Usually　these　myths　focus　around　hearing　and　sight。　If　the　myths　were　true；　what　sense　
might　bee　more　acute　if　the　sense　of　taste　is　lost？　Smell？　Taste？　
10。　What　sense　would　bee　more　acute　if　the　sense　of　touch　was　lost？　Again；　people　can　
sometimes　pensate　for　the　loss　of　a　sense　in　a　variety　of　ways；　but　there　is　no　
pensatory　increase　in　physical　ability　in　the　remaining　senses。　
SUPPLEMENTAL　LECTURE　MATERIAL　

Sensation　and　Perception　

Why　do　we　study　sensation　and　perception？　Primarily　because　it　is　through　the　sensory　systems　
that　we　make　and　maintain　our　contact　with　the　environment。　What　are　some　of　the　reasons　that　
figure　into　this　contact　with　the　environment？　There　are　many　reasons；　but　some　of　the　more　
pertinent　follow。　

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1。　For　purposes　of　munication　to　and　from　the　brain；　between　our　internal　and　external　
environments。　
2。　For　organizational　and　functional　principles　that　are　applicable　across　the　various　sensory　
and　perceptual　systems。　
3。　For　prehension　of　anatomical　structure　at　a　physiological　level。　
4。　For　assistance　with　deficits　in　the　various　systems；　such　as　abnormalities；　deficiencies；　
prosthetics；　and　so　on。　This　is　especially　important　in　vision　and　audition；　in　that　
“normal”　individuals　get　80　percent　of　their　sensory　input　through　vision　and　15—18　
percent　through　audition。　The　remaining　2—5　percent　is　distributed　across　the　other　
various　systems。　
5。　Finally；　for　philosophical　reasons；　to　what　extent　is　our　world　experience　predicated　on　
sensation　and　perception？　On　what　else　could　it　be　predicated？　
Other　principles　and　properties　that　are　characteristic　of　all　sensory　systems　include　the　following：　

1。　Limit