the origin and nature of emotions-第19节

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thereal　vibrations　produce　sight；　air　waves　produce　sound；　microscopic　particles　of　matter　produce　smell。　The　advantage　of　the　distance　ceptors　is　that　they　allow　time　for　orientation；　and　because　of　this　great　advantage　the　majority　of　man's　actions　are　responses　to　their　adequate　stimuli。　As　Sherrington　has　stated；　the　greater　part　of　the　brain　has　been　developed　by　means　of　stimuli　received　through　the　special　senses；　especially　through　the　light　ceptors；　the　optic　nerves。

We　have　just　stated　that　by　means　of　the　distance　ceptors　animals　and　man　orientate　themselves　to　their　distant　environment。　As　a　result　of　the　stimulation　of　the　special　senses　chase　and　escape　are　effected；　fight　is　conducted；　food　is　secured；　and　mates　are　found。　It　is　obvious；　therefore；　that　the　distance　ceptors　are　the　primary　cause　of　continuous　and　exhausting　expenditures　of　energy。　On　the　other　hand；　stimuli　applied　to　contact　ceptors　lead　to　short；　quick　discharges　of　nervous　energy。　　The　child　puts　his　hand　in　the　fire　and　there　is　an　immediate　and　complete　response　to　the　injuring　contact；　he　sees　a　pot　of　jam　on　the　pantry　shelf　and　a　long　train　of　continued　activities　are　set　in　motion；　leading　to　the　acquisition　of　the　desired　object。

The　contact　ceptors　do　not　at　all　promote　the　expenditure　of　energy　in　the　chase　or　in　fight；　in　the　search　for　food　or　for　mates。　Since　the　distance　ceptors　control　these　activities；　one　would　expect　to　find　that　they　control　also　those　organs　whose　function　is　the　production　of　energizing　internal　secretions。　　Over　these　organsthe　thyroid；　the　adrenals；　the　hypophysisthe　contact　ceptors　have　no　control。　Prolonged　laboratory　experimentation　seems　to　prove　this　postulate。　According　to　our　observations；　no　amount　of　physical　trauma　inflicted　upon　animals　will　cause　hyperthyroidism　or　increased　adrenalin　in　the　blood；　while　fear　and　rage　do　produce　hyperthyroidism　and　increased　adrenalin　（Fig。　44）　（Cannon）。　This　is　a　statement　of　far…reaching　importance　and　is　the　key　to　an　explanation　of　many　chronic　diseases　diseases　which　are　associated　with　the　intense　stimulation　of　the　distance　ceptors　in　human　relations。

Stimuli　of　the　contact　ceptors　differ　from　stimuli　of　the　distance　ceptors　in　still　another　important　particular。　　The　adequacy　of　stimuli　of　the　contact　ceptors　depends　upon　their　number　and　intensity；　while　the　adequacy　of　the　stimuli　of　the　distance　ceptors　depends　upon　the　EXPERIENCE　of　the　species　and　of　the　individual。　That　is；　according　to　phylogeny　and　ontogeny　this　or　that　sound；　this　or　that　smell；　this　or　that　sight；　through　association　recapitulates　the　experience　of　the　species　and　of　the　individual　awakens　the　phylogenetic　and　ontogenetic　memory。　　In　other　words；　sights；　sounds；　and　odors　are　symbols　which　awaken　phylogenetic　association。　If　a　species　has　become　adapted　to　make　a　specific　response　to　a　certain　object；　then　that　response　will　occur　automatically　in　an　individual　of　that　species　when　he　hears；　sees；　or　smells　that　object。　Suppose；　for　example；　that　the　shadow　of　a　hawk　were　to　fall　simultaneously　on　the　eyes　of　a　bird；　a　rabbit；　a　cow；　and　a　boy。　That　shadow　would　at　once　activate　the　rabbit　and　the　bird　to　an　endeavor　to　escape；　each　in　a　specific　manner　according　to　its　phylogenetic　adaptation；　the　cow　would　be　indifferent　and　neutral；　while　the　boy；　according　to　his　personal　experience　or　ontogeny；　might　remain　neutral；　might　watch　the　flight　of　the　hawk　with　interest　or　might　try　to　shoot　it。

Each　phylogenetic　and　each　ontogenetic　experience　by　an　indirect　method　develops　its　own　mechanism　of　adaptation　in　the　brain；　and　the　brain　threshold　is　raised　or　lowered　to　stimuli　by　the　strength　and　frequency　of　repetition　of　the　experience。　Thus　through　the　innumerable　symbols　supplied　by　environment　the　distance　ceptors　drive　this　or　that　animal　according　to　the　type　of　brain　pattern　and　the　particular　state　of　threshold　which　has　been　developed　in　that　animal　by　its　phylogenetic　and　ontogenetic　experiences。　The　brain　pattern　depends　upon　his　phylogeny；　the　state　of　threshold　upon　his　ontogeny。　　Each　BRAIN　PATTERN　is　created　by　some　particular　element　in　the　environment　to　which　an　adaptation　has　been　made　for　the　good　of　the　species。　　The　_*state　of　threshold_　depends　upon　the　effect　made　upon　the　individual　by　his　personal　contacts　with　that　particular　element　in　his　environment。　　The　presence　of　that　element　produces　in　the　individual　an　associative　recall　of　the　adaptation　of　his　speciesthat　is；　the　brain　pattern　developed　by　his　phylogeny　becomes　energized　to　make　a　specific　response。　The　intensity　of　the　response　depends　upon　the　state　of　threshold　that　is；　upon　the　associative　recall　of　the　individual's　own　experiencehis　ontogeny。

If　the　full　history　of　the　species　and　of　the　individual　could　be　known　in　every　detail；　then　every　detail　of　that　individual's　conduct　in　health　and　disease　could　be　predicted。　Reaction　to　environment　is　the　basis　of　conduct；　of　moral　standards；　of　manners　and　conventions；　of　work　and　play；　of　love　and　hate；　of　protection　and　murder；　of　governing　and　being　governed；　in　fact；　of　all　the　reactions　between　human　beingsof　the　entire　web　of　life。　To　quote　Sherrington　once　more：　　〃Environment　drives　the　brain；　the　brain　drives　the　various　organs　of　the　body。〃

By　what　means　are　these　adaptations　made？　　What　is　the　mechanism　through　which　adequate　responses　are　made　to　the　stimuli　received　by　the　ceptors？　We　postulate　that　in　the　brain　there　are　innumerable　patterns　each　the　mechanism　for　the　performance　of　a　single　kind　of　action；　and　that　the　brain…cells　supply　the　energyelectric　or　otherwise　by　which　the　act　is　performed；　that　the　energy　stored　in　the　brain…cells　is　in　some　unknown　manner　released　by　the　force　which　activates　the　brain　pattern；　and　that　through　an　unknown　property　of　these　brain　patterns　each　stimulus　causes　such　a　change　that　the　next　stimulus　of　the　same　kind　passes　with　greater　facility。

Each　separate　motor　action　presumably　has　its　own　mechanism　brain　patternwhich　is　activated　by　but　one　ceptor　and　by　that　ceptor　only　when　physical　force　of　a　certain　intensity　and　rate　of　motion　is　applied。　　This　is　true　both　of　the　visible　contacts　affecting　the　nociceptors　and　of　the　invisible　contacts　by　those　intangible　forces　which　affect　the　distance　ceptors。　For　example；　each　variation　in　speed　of　the　light…producing　waves　of　ether　causes　a　specific　reaction　in　the　brain。　For　one　speed　of　ether　waves　the　reaction　is　the　perception　of　the　color　blue；　for　another；　yellow；　for　another；　violet。　Changes　in　the　speed　of　air　waves　meet　with　specific　response　in　the　brain　patterns　tuned　to　receive　impressions　through　the　aural　nerves；　and　so　we　distinguish　differences　in　sound　pitch。　If　we　can　realize　the　infinite　delicacy　of　the　mechanisms　adapted　to　these　infinitesimal　variations　in　the　speed　and　intensity　of　invisible　and　intangible　stimuli；　it　will　not　be　difficult　to　conceive　the　variations　of　brain　patterns　which　render　possible　the　specific　responses　to　the　coarser　contacts　of　visible　environment。

Each　brain　pattern　is　adapted　for　but　one　type　of　motion；　and　so　the　specific　stimuli　of　the　innumerable　ceptors　play　each　upon　its　own　brain　pattern　only。　　In　addition；　each　brain　pattern　can　react　to　stimuli　applied　only　within　certain　limits。　Too　bright　a　light　blinds；　too　loud　a　sound　deafens。　　No　mechanism　is　adapted　for　waves　of　light　above　or　below　a　certain　rate　of　speed；　although　this　range　varies　in　different　individuals　and　in　different　species　according　to　the　training　of　the　individual　and　the　need　of　the　species。

We　have　already　referred　to　the　fact　that　there　is　no　receptive　mechanism　adapted　to　the　stimuli　from　the　_x_…ray；　from　the　high…speed　bullet；　from　electricity。　　So；　too；　there　are　innumerable　forces　in　nature　which　can　excite　in　man　no　adaptive　response；　since　there　exist　in　man　no　brain　patterns　tuned　to　their　waves；　as　in　the　case　of　certain　ethereal　and　radioactive　forces。

On　this　mechanistic　basis　the　emotions　may　be　explained　as　activations　of　the　entire　motor　mechanism　for　fighting；　for　escaping；　for　copulating。　The　sight　of　an　enemy　stimulates　in　the　brain　those　patterns　formed　by　the　previous　experiences　of　the　individual　with　that　enemy；　and　also　the　experiences　of　the　race　whenever　an　enemy　had　to　be　met　and　overcome。　Each　of　these　many　brain　patterns　in　turn　activates　that　part　of　the　body　through　which　lies　the　path　of　its　own　adaptive　response　those　parts　including　the　special　energizing　or　activating　organs。　Laboratory　experiments　show　that　in　an　animal　driven　strongly　by　emotion　the　following　changes　may　be　seen：　　（1）　A　mobilization　of　the　energy…giving　compound　in　the　brain…cells；　evidenced　by　a　primary　increase　of　the　Nissl　substance　and　a　later　disappearance　of　this　substance　and　the　deterioration　of　the　cells　（Figs。　5　and　13）；　（2）　increased　output　of　adrenalin　（Cannon）；　of　thyroid　secretion；　of　glycogen；　and　an　increase　of　the　power　of　oxidation　in　the　muscles；　（3）　accelerated　circulation　and　respiration　with　increased　body　temperature；　（4）　altered　metabolism。　　All　these　are　adaptations　to　increase　the　motor　efficiency　of　the　mechanism。　　In　addition；　we　find　an　inhibition　of　the　functio