In 1972, the results of polygraph tests were inadmissible in Alaska courts. With some notable exceptions, they are still inadmissible. A 2015 Alaska Appeals Court case moved the needle a bit closer to the admissibility of these so-called “lie detector” tests, but the court noted that issues remain:
“[T] wo experts vigorously disagreed as to whether it was possible to accurately discern, from the physiological data collected during a polygraph examination, whether a person was being truthful in their answers during the exam… Dr. Raskin put the accuracy rate of a well-conducted polygraph examination at somewhere between 89 and 98 percent, while Dr. Iacono testified that the accuracy rate was considerably lower—somewhere close to 70 percent, on average.”
The dueling experts clearly reveal the core controversy: there is no scientific evidence that any pattern of physiological reactions is unique to deception. An honest person may be nervous when answering truthfully and a dishonest person may be non-anxious.
A particular problem is that polygraph research has not separated placebo-like effects (the subject’s belief in the efficacy of the procedure) from the actual relationship between deception and their physiological responses. One reason that polygraph tests may appear to be accurate is that subjects who believe that the test works and that they can be detected may confess or will be very anxious when questioned. If this view is correct, the lie detector might be better called a fear detector [emphasis added]. (American Psychological Association; The Truth About Lie Detectors, 2004)
WALTER GILMOUR: “We circulated a composite in the newspapers, produced lots of tips and an extensive log which revealed more about sexual abuse than one cares to believe, but no real breaks in the case. Meanwhile, Greg’s attorney’s were insisting he be given a polygraph test, which I resisted because if he passed it, they wanted me to stop treating him like a suspect. I was with Yogi Berra on this one: ‘It ain’t over ’til it’s over.’ But while I was out of town on police business, my superiors at the State Troopers gave him the box anyway.”
When Alaska State Troopers administered the polygraph test to Greg Nicholas in 1972, it was all about it being a fear detector. Greg’s emotional state prior to the test seemed to indicate he was somehow involved in Beth’s death. The polygraph hoped to test whether that impression matched Greg’s physiological responses.
Greg passed the polygraph test. That result indicated he was not responsible for the death or murder of Beth van Zanten. But… The polygraph operator admitted there was a possibility that the questions he asked were not geared to the “actual circumstances of the investigation.”
The operator indicated that Greg showed deception in response to two questions:
- Have you ever participated in an unnatural sex act?
- Have you ever used marijuana?
One supposes that more than a few folks would get “caught” on those two questions, whatever their involvement (or lack thereof). Gilmour was stuck. Or nearly so. There was one more interview subject in his stack of possibilities. That and the lab results.
Purchase Butcher, Baker