[Updated Monday, 9 April 2007] In a journalistic nadir, NBC Dateline on Sunday, 8 April 2007 presented a story, “Diane Zamora: ‘I’m Not a Killer,'” prominently featuring the results of a polygraph “test” that Dateline arranged for Zamora, a former U.S. Naval Academy midshipman who is serving a life sentence for murder in a Texas prison. Dateline’s producers should have known — had they done their homework — that polygraph “testing” is not only “not foolproof,” as reporter Stone Philips allows, but in fact has no scientific basis at all. Additional information on the broadcast is available in “Diane Zamora and the Lie Detector Test Results” on the Inside Dateline blog.
The following is an excerpt from the program transcript:
After hearing her story and taking a closer look at the evidence, do you believe Diane Zamora? Did she go along that night to question Adrianne Jones, or to kill her? Before you make up your mind, there’s one more piece of the puzzle you might want to consider: Having lost her appeal in the Texas courts, Zamora did something this past February she’s wanted to do for years. With the approval of her lawyer, she took a lie detector test arranged by ‘Dateline.’
Exactly one week after she had taken the polygraph examination, we saw Zamora again. From the expression on her face, it was clear she had no idea what the results were. She was about to find out.
Stone Phillips, Dateline correspondent: So, you took the polygraph. How did it go? What was it like?
Diane Zamora: I was very nervous.
Phillips: You spoke with the examiner at length before the test began. He went over every question with you in advance.
Zamora: Yeah, he–well, he told me all the questions. And went over what my answers would be to each question.
Phillips: And then he hooked you up for the examination.
Zamora: Uh-huh. Yes, sir.
Phillips: The examiner reported that you altered your breathing at certain points. What’s called a “counter measure” to try to influence the outcome of the test.
Zamora: No, I was so nervous. I hadn’t even slept the night before.
Phillips: The examiner says he repeatedly asked you to breathe normally.
Zamora: No, he asked me–
Phillips: To stop with the exaggerated hyperventilating–
Zamora: No, it–
Phillips: And that you did not do that. You continued to do it throughout the exam.
Zamora: I didn’t hyperventilate. I was trying to breathe deep to calm myself. Cause, I was really very nervous. And I remember at one point he told me I was breathing to breathe. So, I tried not to breathe as deeply as I was.
Phillips: Despite the unusual breathing, here’s what the examiner found. We’ll–we’ll go through ’em.
(1) Did you tell David to kill Adrian Jones? Your answer?
(2) Did you strike Adrian Jones?
3) Were you truthful when you stated that the detective read and showed you David’s statement before you prepared your own? Deception.
4) On the questions about, “Did you plan with David Graham to cause the death of Adrianne Jones.” Your answer….
Phillips: Significant physiological responses indicating deception. Deception was indicated on every one of the relevant questions in the case.
Zamora: Then that should tell you something, cause you know I didn’t strike her. I proved that already.
Phillips: So, why would a polygraph test indicate that you were being deceptive, when you answered that you hadn’t struck her?
Zamora: I don’t know. Like I said, I was nervous. I guess what made me so nervous is hope. Something I previously didn’t have. And that’s what was so scary–hope–and not wanting it snatched away from me. That made me very nervous.
We shared the results with two independent experts. They told us that because of Zamora’s altered breathing they would have ruled the exam inconclusive–no opinion due to probable countermeasures….
But one agreed Zamora’s responses to all of the key questions indicated deception. And the examiner who administered the test said, in spite of the counter measures, in his opinion, Zamora failed.
Phillips: Many examiners, if they felt that you were altering your breathing and ignoring their warnings not to, would stop the test right there. I’m just gonna ask you very directly Diane, did you try to influence the outcome of this examination?
Zamora: No, I tried to keep myself calm.
Phillips: It’s not admissible in court. It is not foolproof. It is just another piece of the puzzle.
Zamora: To me it just doesn’t make sense. And I know it doesn’t hold in the court. I know that. But it was important to me. Important to my family. And that’s what really mattered to me. I went in with good intentions and high hopes.
Phillips: Well, it took some bravery to take this test. It would also show some bravery to accept the results. Do you accept the results?
Zamora: I don’t believe them. I know that they’re not true. But like I said, I’m not giving up.
Dateline offers these lie detector results as a “piece of the puzzle.” But they are, in fact, evidence of nothing except perhaps a lack of competence (or journalistic integrity) on the part of Dateline’s producers. As mentioned earlier, polygraph testing has no scientific basis to begin with. Moreover, neither hyperventilation nor deep breathing are genuine polygraph countermeasures because they cannot in any way help a person to pass a polygraph test. Polygraph operators are taught that examinees should breathe at a rate of about 15-30 breaths (in and out) per minute, and that anything outside that range is evidence of purposeful manipulation. But it is not at all unusual for people to breath more slowly and deeply in a stressful situation, just as it appears Diane Zamora did.
Had Zamora been trying to beat the polygraph, the way to do it would have been to ensure that her breathing remained within the 15-30 breaths per minute range and to covertly augment her reactions to the so-called “control” questions using techniques that polygraph operators have no demonstrated ability to detect. For details on how this can be accomplished, see AntiPolygraph.org’s free e-book, The Lie Behind the Lie Detector.
Zamora’s polygraph results yielded no evidence that could help Dateline’s viewers to reach an informed opinion regarding the facts of her case, and it is deplorable that an ostensibly serious news program resorted to such a blatant ratings gimmick.