Blood on the Table_Greatest Cases of New York City's Office of the Chief Medical Examiner by Colin Evans

Author:Colin Evans [Evans, Colin]
Language: eng
Format: epub
Tags: Science
ISBN: 9780425219379
Amazon: B001269F9S
Goodreads: 2889834
Publisher: Berkley
Published: 2008-03-04T00:00:00+00:00

Thoracic respiration

Abdominal respiration

Perspiration (registered by minuscule changes in skin conductivity of electricity occurring at the fingertip)

Blood pressure

Blood volume

These five responses are then plotted along a horizontal graph, with the location of questions marked at the bottom of the printout. How the questions are framed is critical. Because individuals react differently, the examiner needs to know what triggers a “lie” response in that particular subject. To this end, each test contains certain “control” questions, to which the subject is directed to answer untruthfully. The concomitant anxiety usually registers as a blip on the graph. Once this untruthful benchmark has been established, the actual test can begin.

Numerous questions—some relevant to the case, some not—are fired at the subject. Each response is assigned a number from -3 (indicating a strong negative correlation) to +3 (indicating a strong positive correlation), measured by comparing the relevant response to the previously established controls. Psychology plays its part, with the skilled examiner constantly reminding the subject of just how accurate the polygraph is in catching any lies told.

Once all the responses are added together, a total score of +6 indicates a strong presumption that the subject is lying. Scores that fall between -5 and +5 are not admissible, because they are not felt to be a strong enough indication of veracity.

While no one disputes that polygraphs measure perceptible changes in human response, there can be no guarantee that these changes are prompted by the act of lying. Because stress plays a big factor in any polygraph test—even truthful subjects occasionally send the styluses haywire—much depends on how the examiner interprets the data. And herein lies much of the controversy. Give the same polygraph results to two different examiners and, as tests have shown, it is entirely possible that they will reach opposing conclusions as to the subject’s truthfulness.

Supporters of the polygraph attribute such discrepancies to poor schooling and a lack of experience. A properly trained examiner, they claim, armed with a good instrument, will catch 95 percent of all liars. Critics put the figure much lower and say that with minimal practice almost anyone can be taught how to “beat the machine” by deliberately manipulating their physiological responses to give false positives.

Someone who notably failed to beat the machine was Colin Carpi. Three times he was hooked up to the polygraph, and three times he gave responses that indicated deception.

But before the prosecutors could lay their case before a jury, they first of all had to get Carpi into court. And that was proving to be hellishly difficult. Dominating all else was the question of jurisdiction. Although the body had been found in New York, there was plenty of evidence to suggest that Laura had been killed in her Princeton house and then transported to the East River where her body was dumped. After some lukewarm interstate wrangling—New York really wanted to wash its hands of what had been a humiliating public embarrassment—New Jersey found itself saddled with the prosecution of Colin Carpi.

It was a strange case right from the beginning.

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.