the origin and nature of emotions-第21节

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sponse　and　occurs　only　as　a　result　of　contact　ceptor　stimulation　by　physical　injury；　infection；　anemia；　or　obstruction；　we　may　well　inquire　which　part　of　the　nerve　mechanism　is　the　site　of　the　phenomenon　of　pain。　Is　it　the　nerve…ending；　the　nerve…trunk；　or　the　brain？　　That　is；　is　pain　associated　with　the　physical　contact　with　the　nerve…ending；　or　with　the　physical　act　of　transmission　along　the　nerve…trunk；　or　with　the　change　of　brain…cell　substance　by　means　of　which　the　motor…producing　energy　is　released？

We　postulate　that　the　pain　is　associated　with　the　discharge　of　energy　from　the　brain…cells。　If　this　be　true；　then　if　every　nociceptor　in　the　body　were　equally　stimulated　in　such　a　manner　that　all　the　stimuli　should　reach　the　brain…cells　simultaneously；　then　the　cells　would　find　themselves　in　equilibrium　and　no　motor　act　would　be　performed。　But　if　all　the　pain　nerve　ceptors　but　one　were　equally　stimulated；　and　this　one　more　strongly　stimulated　than　the　rest；　then　this　one　would　gain　possession　of　the　final　common　pathwould　cause　a　muscular　action　and　the　sensation　of　pain。

It　is　well　known　that　when　a　greater　pain　or　stimulus　is　thrown　into　competition　with　a　lesser　one；　the　lesser　is　submerged。　Of　this　fact　the　school…boy　makes　use　when　he　initiates　the　novice　into　the　mystery　of　the　painless　pulling　of　hair。　The　simultaneous　but　severe　application　of　the　boot　to　the　blindfolded　victim　takes　complete　but　exclusive　possession　of　the　final　common　path　and　the　hair　is　painlessly　plucked　as　a　result　of　the　triumph　of　the　boot　stimulus　over　the　pull　on　the　hair　in　the　struggle　for　the　final　common　path。

Persons　who　have　survived　a　sudden；　complete　exposure　to　superheated　steam；　or　whose　bodies　have　been　enwrapped　in　flame；　testify　that　they　have　felt　no　pain。　　As　this　absence　of　pain　may　be　due　to　the　fact　that　the　emotion　of　fear　gained　the　final　common　path；　to　the　exclusion　of　all　other　stimuli；　we　are　trying　by　experimentation　to　discover　the　effects　of　simultaneous　painful　stimulation　of　all　parts　of　the　body。　The　data　already　in　hand；　and　the　experiments　now　in　progress；　in　which　anesthetized　animals　are　subjected　to　powerful　stimuli　applied　to　certain　parts　of　the　body　only；　or　simultaneously　to　all　parts　of　the　body；　lead　us　to　believe　that　in　the　former　case　the　brain…cells　become　stimulated　or　hyperchromatic；　while　in　the　latter　case　no　brain…cell　changes　occur。　　We　believe　that　our　experiments　will　prove　that　an　equal　and　simultaneous　stimulation　of　all　parts　of　the　body　leaves　the　brain…cells　in　a　state　of　equilibrium。　Our　theory　of　pain　will　then　be　well　sustained；　not　only　by　common　observation；　but　by　experimental　proof；　and　so　the　mechanistic　view　will　be　found　in　complete　harmony　with　another　important　reaction。

We　have　stated　that　when　a　number　of　contact　stimuli　act　simultaneously；　the　strongest　stimulus　will　gain　possession　of　the　final　common　path　the　path　of　action。　　When；　however；　stimuli　of　the　distance　ceptors　compete　with　stimuli　of　the　contact　ceptors；　the　contact…ceptor　stimuli　often　secure　the　common　path；　not　because　they　are　stronger　or　more　important；　but　because　they　are　immediate　and　urgent。　In　many　instances；　however；　the　distance…ceptor　stimuli　are　strong；　have　the　advantage　of　a　lowered　threshold；　and　therefore　compete　successfully　with　the　immediate　and　present　stimuli　of　the　contact　ceptors。　　In　such　cases　we　have　the　interesting　phenomenon　of　physical　injury　without　resultant　pain　or　muscular　response。　The　distance…ceptor　stimuli　which　may　thus　triumph　over　even　powerful　contact…ceptor　stimuli　are　those　causing　strong　emotionsas　great　anger　in　fighting；　great　fear　in　a　battle；　intense　sexual　excitement。　Dr。　Livingstone　has　testified　to　his　complete　unconsciousness　to　pain　during　his　struggle　with　a　lion；　although　he　was　torn　by　teeth　and　claws；　his　fear　overcame　all　other　impressions。　By　frequently　repeated　stimulation　the　Dervish　secures　a　low　threshold　to　the　emotions　caused　by　the　thought　of　God　or　the　devil；　and　his　emotional　excitement　is　increased　by　the　presence　of　others　under　the　same　stimulation；　emotion；　therefore；　secures　the　final　common　path　and　he　is　unconscious　of　pain　when　he　lashes；　cuts；　and　bruises　his　body。　　The　phenomena　of　hysteria　may　be　explained　on　this　basis；　as　may　the　unconsciousness　of　passing　events　in　a　person　in　the　midst　of　a　great　and　overwhelming　grief。　By　constant　practice　the　student　may　secure　the　final　common　path　for　such　impressions　as　are　derived　from　the　stimuli　offered　by　the　subject　of　his　study；　and　so　he　will　be　oblivious　of　his　surroundings。　Concentration　is　but　another　name　for　a　final　common　path　secured　by　the　repetition　and　summation　of　certain　stimuli。

If　our　premises　are　sustained；　then　we　can　recognize　in　man　no　will；　no　ego；　no　possibility　for　spontaneous　action；　for　every　action　must　be　a　response　to　the　stimuli　of　contact　or　distance　ceptors；　or　to　their　recall　through　associative　memory。　　Memory　is　awakened　by　symbols　which　represent　any　of　the　objects　or　forces　associated　with　the　act　recalled。　Spoken　and　written　words；　pictures；　sounds；　may　stimulate　the　brain　patterns　formed　by　previous　stimulation　of　the　distance　ceptors；　while　touch；　pain；　temperature；　pressure；　may　recall　previous　contact…ceptor　stimuli。　　Memory　depends　in　part　upon　the　adequacy　of　the　symbol；　and　in　part　upon　the　state　of　the　threshold。　If　one　has　ever　been　attacked　by　a　snake；　the　threshold　to　any　symbol　which　could　recall　that　attack　would　be　low；　the　later　recall　of　anything　associated　with　the　bite　or　its　results　would　produce　in　memory　a　recapitulation　of　the　whole　scene；　while　even　harmless　snakes　would　thereafter　be　greeted　with　a　shudder。　On　the　other　hand；　in　a　child　the　threshold　is　low　to　the　desire　for　the　possession　of　any　new　and　strange　object；　in　a　child；　therefore；　to　whom　a　snake　is　merely　an　unusual　and　fascinating　object；　there　is　aroused　only　curiosity　and　the　desire　for　the　possession　of　a　new　plaything。

If　we　are　to　attribute　to　man　the　possession　of　a　governing　attribute　not　possessed　by　other　parts　of　the　animal　creation；　where　are　we　to　draw　the　boundary　line；　and　say　〃here　the　ego　the　willthe　reasonemerges〃？　What　attribute；　after　all；　has　man　which　in　its　ultimate　analysis　is　not　possessed　by　the　lowest　animals　or　by　the　vegetable　creation；　even？　　From　the　ameba；　on　through　all　the　stages　of　animal　existence；　every　action　is　but　a　response　to　an　adequate　stimulus；　and　as　a　result　of　adequate　stimuli　each　step　has　been　taken　toward　the　higher　and　more　intricate　mechanisms　which　play　the　higher　and　more　intricate　parts　in　the　great　scheme　of　nature。

The　Venus　fly…trap　responds　to　as　delicate　a　stimulus　as　do　any　of　the　contact　ceptors　of　animals；　and　the　motor　activity　resulting　from　the　stimulus　is　as　complex。　　To　an　insect…like　touch　the　plant　responds；　to　a　rough　contact　there　is　no　response；　that　is；　the　motor　mechanism　of　the　plant　has　become　attuned　to　only　such　stimuli　as　simulate　the　contact　of　those　insects　which　form　its　diet。　It　catches　flies；　eats　and　digests　them；　and　ejects　the　refuse　（Fig。　47）。　The　ameba　does　no　less。　　The　frog　does　no　more；　excepting　that　in　its　place　in　creation　a　few　more　reactions　are　required　for　its　sustenance　and　for　the　propagation　of　its　species。　Man　does　no　more；　excepting　that　in　man's　manifold　relations　there　are　innumerable　stimuli；　for　meeting　which　adequately；　innumerable　mechanisms　have　been　evolved。　　The　motor　mechanism　of　the　fly…trap　is　perfectly　adapted　to　its　purpose。　The　motor　mechanism　of　man　is　adapted　to　its　manifold　uses；　and　as　new　environmental　influences　surround　him；　we　must　believe　that　new　adaptations　of　the　mechanism　will　be　evolved　to　meet　the　new　conditions。

Is　not　this　conception　of　man's　activities　infinitely　more　wonderful；　and　infinitely　more　comprehensible　than　is　the　conception　that　his　activities　may　be　accounted　for　by　the　existence　of　an　unknown；　unimaginable；　and　intangible　force　called　〃mind〃　or　〃soul〃？

We　have　already　shown　how　the　nerve　mechanism　is　so　well　adapted　to　the　innumerable　stimuli　of　environment　that　it　can　accurately　transmit　and　distinguish　between　the　infinite　variations　of　speed　in　the　ether　waves　producing　light；　and　the　air　waves　producing　sound。　Each　rate　of　vibration　energizes　only　the　mechanism　which　has　been　attuned　to　it。　　With　marvelous　accuracy　the　light　and　sound　waves　gain　access　to　the　nerve　tissue　and　are　finally　interpreted　in　terms　of　motor　responses；　each　by　the　brain　pattern　attuned　to　that　particular　speed　and　intensity。　　So　stimuli　and　resultant　actions　multiplied　by　the　total　number　of　the　motor　patterns　in　the　brain　of　man　give　us　the　sum　total　of　his　life's　activities　they　constitute　his　life。

As　in　evolutionary　history　the　permanence　of　an　adaptation　of　the　body　mechanism　depends　upon　its　value　in　the　preservation　of　the　life　of　the　individual　and　upon　its　power　to　increase　the　value　of　the　individual　to　the　race；　so　the　importance　and　truth　of　these　postulates　and　theories　may　well　be　judged　on　the　same　basis。

The　fundamental　instincts　of　all　living　matter　are　self…preservation　and　the　propagation　of　the　species。　　The　instinct　for　self…preservation　causes　a　plant　to　turn　away　from　cold　and　damagin