criminal psychology-第59节

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；　d；l；　m；　n；　etc。；　a　fourth　works　slowly　and　rather　inaccurately；　getting：　a；　c；　d；f；　h；　i；etc。　Such　variations　multiply；　and　when　various　observers　of　the　same　event　describe　it　they　do　it　according　to　their　different　characteristics。　And　the　differences　may　be　tremendous。　Substitute　numerals　for　letters　and　the　thing　becomes　clear。　The　relative　slowness　of　our　apprehension　of　visual　elements　has　the　other　consequence　that　we　interpolate　objects　in　the　lacun　of　vision　_*according　to　our　expectations_。　The　best　example　of　this　sort　of　thing　would　be　the　perception　of　assault　and　battery。　When　ten　people　in　an　inn　see　how　A　raises　a　beer　glass　against　B's　head；　five　expect：　‘‘Now　he'll　pound　him；''　and　five　others：　‘‘Now　he'll　throw　it。''　If　the　glass　has　reached　B's　head　none　of　the　ten　observers　have　seen　how　it　reached　there；　but　the　first　five　take　their　oath　that　A　pounded　B　with　the　glass；　and　the　other　five　that　he　threw　it　at　B's　head。　And　all　ten　have　really　seen　it；　so　firmly　are　they　convinced　of　the　correctness　of　their　swift　judgment　of　expectation。　Now；　before　we　treat　the　witness　to　some　reproach　like　untruth；　inattention；　silliness；　or　something　equally　nice；　_*we_　had　better　consider　whether　his　story　is　not　true；　　and　whether　the　difficulty　might　not　really　lie　in　the　imperfection　of　our　own　sensory　processes。　This　involves　partly　what　Liebmann　has　called　‘‘anthropocentric　vision；''　i。　e。；　seeing　with　man　as　the　center　of　things。　Liebmann　further　asserts；　‘‘that　we　see　things　only　in　perspective　sizes；　i。　e。；　only　from　an　angle　of　vision　varying　with　their　approach；　withdrawal　and　change　of　position；　but　in　no　sense　as　definite　cubical；　linear；　or　surface　sizes。　The　apparent　size　of　an　object　we　call　an　angle　of　vision　at　a　certain　distance。　But；　what　indeed　is　the　different；　true　size？　We　know　only　relations　of　magnitude。''　This　description　is　important　when　we　are　dealing　with　testimony　concerning　size。　It　seems　obvious　that　each　witness　who　speaks　of　size　is　to　be　asked　whence　he　had　observed　it；　but　at　the　same　time　a　great　many　unexpected　errors　occur；　especially　when　what　is　involved　is　the　determination　of　the　size　of　an　object　in　the　same　plane。　One　need　only　to　recall　the　meeting　of　railway　tracks；　streets；　alleys；　etc。；　and　to　remember　how　different　in　size；　according　to　the　point　of　view　of　the　witness；　various　objects　in　such　places　must　appear。　Everybody　knows　that　distant　things　seem　smaller　than　near　ones；　but　almost　nobody　knows　what　the　difference　amounts　to。　For　examples　see　Lotze；　‘‘Medical　Psychology；''　Leipzig；　1852。

In　addition　we　often　think　that　the　clearness　of　an　object　represents　its　distance　and　suppose　that　the　first　alone　determines　the　latter。　But　the　distinctness　of　objects；　i。　e。；　the　perceptibility　of　a　light…impression；　depends　also　upon　the　absolute　brightness　and　the　differences　in　brightness。　The　latter　is　more　important　than　is　supposed。　Try　to　determine　how　far　away　you　can　see　a　key…hole　when　the　wall　containing　the　door　is　in　the　shadow；　and　when　there　is　a　window　opposite　the　key…hole。　A　dark　object　of　the　size　of　a　key…hole　will　not　be　visible　at　one　hundredth　of　the　distance　at　which　the　key…hole　is　perceived。　Moreover；　the　difference　in　intensity　is　not　alone　in　consideration；　the　intensity　of　the　object　_*with　regard　to　its　background_　has　yet　to　be　considered。　Aubert　has　shown　that　the　accuracy　of　the　distinction　is　the　same　when　a　square　of　white　paper　is　looked　at　from　an　angle　of　18''；　and　when　conversely　a　square　of　black　paper　on　white　background　is　looked　at　from　an　angle　of　85''。　‘‘When　we　put　a　gray　paper　in　the　sunshine；　it　may　become　objectively　brighter　than　white　paper　in　shadow。　But　this　does　not　prevent　us　from　knowing　one　as　gray　and　the　other　as　pure　white。　We　separate　the　color　of　the　object　from　the　intensity　of　the　incident　light。''　But　this　is　not　always　so　simple；　inasmuch　as　　we　know　in　the　case　in　hand　which　paper　is　gray　and　which　white；　which　is　in　the　sunlight　and　which　in　the　shadow。　But　if　these　facts　are　not　known　mistakes　often　occur　so　that　a　man　dressed　in　dark　clothes　but　in　full　light　will　be　described　as　wearing　lighter　clothes　than　one　who　wears　light　clothes　in　the　shadow。

Differences　of　illumination　reveal　a　number　of　phenomena　difficult　to　explain。　Fechner　calls　attention　to　the　appearance　of　stars：　‘‘At　night　everybody　sees　the　stars；　in　daylight　not　even　Sirius　or　Jupiter　is　seen。　Yet　the　absolute　difference　between　those　places　in　the　heavens　where　the　stars　are　and　the　environing　places　is　just　as　great　as　in　the　nightthere　is　only　an　increase　in　illumination。''　Of　still　greater　importance　to　us　is　the　circumstance　noted　but　not　explained　by　Bernstein。　If；　in　daylight；　we　look　into　a　basement　room　from　outside；　we　can　perceive　nothing；　almost；　everything　is　dark；　even　the　windows　appear　black。　But　in　the　evening；　if　the　room　is　ever　so　slightly　illuminated；　and　we　look　into　it　from　outside；　we　can　see　even　small　articles　distinctly。　Yet　there　was　much　intenser　light　in　the　room　in　question　during　the　day　than　the　single　illumination　of　the　night　could　have　provided。　Hence；　it　is　asserted；　the　difference　in　this　case　is　a　standard　one。　In　open　day　the　eye　is　accustomed　to　the　dominating　brightness　of　daylight；　beside　which　the　subdued　illumination　of　the　room　seems　relatively　dark。　But　in　the　evening　one　is　in　the　dark；　and　hence　even　the　little　light　of　a　single　candle　is　enough　to　enable　one　to　see。　That　this　explanation　is　untrue　is　shown　by　the　fact　that　the　phenomenon　is　not　regulated　even　when　the　circumstances　in　question　are　made　identical。　If；　for　example；　you　approach　the　window　in　daylight　with　your　eyes　shut；　lean　your　forehead　against　the　pane　and　shut　out　the　light　on　the　sides　with　your　hands；　and　then　open　your　eyes；　you　see　as　little　in　the　room　as　when　you　looked　into　it　without　performing　this　ceremony。　So　again；　if　during　the　night　you　gazed　at　some　near…by　gas　lamp　and　then　glanced　into　the　room；　there　is　only　a　few　moments'　indistinctness　at　most；　after　that　the　single　candle　is　enough。　The　reason；　then；　must　be　different　from　the　assigned　onebut　whatever　it　is；　we　need　only　to　maintain　that　immediate　judgment　concerning　numerous　cases　involving　situations　of　this　kind　would　be　overhasty。　It　is　often　said　that　a　witness　was　able　to　see　this　or　that　under　such　and　such　illumination；　or　that　he　was　unable　to　see　it；　although　he　denies　his　ability　or　inability。　The　only　solution　of　such　contradictions　is　an　experiment。　The　attempt　must　be　made　either　by　the　judge　or　some　reliable　　third　person；　to　discover　whether；　under　the　same　conditions　of　illumination；　anything　could　be　seen　at　the　place　in　question　or　not。

As　to　_*what_　may　be　seen　in　the　distance；　experiment　again；　is　the　best　judge。　The　human　eye　is　so　very　different　in　each　man　that　even　the　acute　examination　into　what　is　known　of　the　visual　image　of　the　Pleiades　shows　that　the　_*average_　visual　capacity　of　classic　periods　is　no　different　from　our　own；　but　still　that　there　was　great　variety　in　visual　capacity。　What　enormous　visual　power　is　attributed　to　half…civilized　and　barbarous　peoples；　especially　Indians；　Esquimos；　etc。！　Likewise　among　our　own　people　there　are　hunters；　mountain　guides；　etc。；　who　can　see　so　clearly　in　the　distance　that　mere　stories　about　it　might　be　fables。　In　the　Bosnian　campaign　of　1878　we　had　a　soldier　who　in　numerous　cases　of　our　great　need　to　know　the　enemy's　position　in　the　distance　could　distinguish　it　with　greater　accuracy　than　we　with　our　good　field…glasses。　He　was　the　son　of　a　coal…miner　in　the　Styrian　mountains；　and　rather　a　fool。　Incidentally　it　may　be　added　that　he　had　an　incredible；　almost　animal　power　of　orientation。

As　we　know　little　concerning　far…sightedness；　so　also　we　are　unable　to　define　what　near…sighted　people　can　see。　Inasmuch　as　their　vision　does　not　carry；　they　are　compelled　to　make　intellectual　supplementations。　They　observe　the　form；　action；　and　clothes　of　people　more　accurately　than　sharp…eyed　persons；　and　hence　recognize　acquaintances　at　a　greater　distance　than　the　latter。　Therefore；　before　an　assertion　of　a　short…sighted　man　is　doubted　an　experiment　should　be　made；　or　at　least　another　trustworthy　short…sighted　person　should　be　asked　for　his　opinion。

The　background　of　objects；　their　movement　and　form　have　decided　effects　on　the　difference　in　visual　perception。　It　is　an　ancient　observation　that　lengthy　objects　like　poles；　wires；　etc。；　are　visible　at　incomparably　greater　distances　than；　e。　g。；　squares　of　the　same　length。　In　examination　it　has　been　shown　that　the　boundary　of　accurate　perception　can　hardly　be　determined。　I　know　a　place　where　under　favorable　illumination　taut；　white　and　very　thin　telephone　wires　may　be　seen　at　a　distance　of　more　than　a　kilometer。　And　this　demands　a　very　small　angle　of　vision。

Humboldt　calls　attention　to　the　large　number　of　‘‘optical　fables。''　He　assures　us　that　it　is　certainly　untrue　that　the　stars　may　be　seen　in　daylight　from　a　deep　well；　from　mines；　or　high　mountains；　although　this　has　been　repeatedly　affirmed　since　Aristotle。

The　explanation　of　our　power　to　see　very　thin；　long　objects　at　　a　very　great　distance；　is　not　our