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Detektory lzi

Detektory lzi. Zdenek Buchlak. Loz . Nie je opakom pravdy. Pravda/nepravda je vyjadrenim skutocnosti. Podstata lzi je v snahe oklamat. Historia. Zapadna afrika : pomocou vtacich vajec, predpoklad nervozity pri lzi Cina : pouzitim ryze. Povod polygrafu: William Monton Marston - 1913

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Detektory lzi

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  1. Detektory lzi Zdenek Buchlak

  2. Loz • Nie je opakom pravdy. • Pravda/nepravda je vyjadrenim skutocnosti. Podstata lzi je v snahe oklamat.

  3. Historia • Zapadna afrika: pomocou vtacich vajec, predpoklad nervozity pri lzi • Cina: pouzitim ryze

  4. Povod polygrafu: William Monton Marston - 1913 - student psychologie na Harvard - zariadenie meralo systolicky tlak krvi John A. Larson - meranie tlaku krvi a galvanicke reakcie koze - prvy krat pouzite v praxi - prvy polygraf

  5. Postup - predtestove otazky - mix testovych otazok: irelevantne, pravdepodobne lzi, relevantne Spolahlivost: - nemeria loz ako taku, meria fiziologicke reakcie spojene s emocionalnymi, je nespolahlivy - Aldrich Ames: usvedceny zo spionaze pre ZSSR, 2x oklamal polygraf,

  6. VSA • Voice stress analysis • 1988 – National Institut for Truth Verification • Hlasovy zaznam vyhodnocovany pocitacom • Mikrozachvevy vo frekvencnej modulacii hlasu • Frekvencia rastie pri lzi • Sporna spolahlivost

  7. Encefalografia • Neurofiziologicka metoda, skuma el.aktivitu mozgu • Vysledok je EEG (elektroencefalogram) • Pomocou elektrod na hlave subjektu • BRAIN FINGERPRINTING • Vyuziva encefalografiu • Skumanim mozgovych vln a ich zmien • Pri vonkajsom (vizualnom, …) stimule dochadza k zmenam • Signal P300 v mozgu vznika cca 300 ms po konfrontacii so stimulom • Nedetekuje loz, urci ci subjekt spoznal stimul (vrazedna zbran, tvar obete…)

  8. IRMf • Zobrazuje magneticku rezonanciu mozgu • Rozne casti mozgu reaguju na rozne impulzy (zavit pod spankovym lalokom je spojeny s rozpoznavanim tvare atd.) • Relativne doverihodne. V podstate sa neda oklamat

  9. Zaujimavosti • Clovek, ktory zaviedol polygraf u CIA veril, ze rastliny dokazu citat ludske myslienky • Najdlhsie skolenie polygrafie trva 14 tyzdnov, co je polovica dlzky studia na holica • Podla prieskumu DDP (Department of Defense Polygraph) ma nevinny cernoch vacsiu sancu neuspiet na detektore lzi ako nevinny beloch

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