posted 09-14-2009 06:17 PM
The Silent-answer-test and Yes-test are different animals than yes-answered RQs in a CQT.The SAT is an attempt to reduce the movement or activity noise introduced by act of answering. It may also give a deceptive person a different set of cognitive delemmas - whether to lie or tell the truth while answering silently.
The Yes-test is an attempt to reframe the activities of the truthful or deceptive person, and works by instructing the examinee to answer 'yes' (now purportedly lying) to questions which were answered with 'no' during the pretest interview and review of the test questions.
Yes-answered RQs are confirmatory questions, which seems to be a form of attempting to use the polygraph as a truth-detector.
I think Skip is correct that the examinee reacts because of what he must answer (the stimulus question), not the answer itself. To suggest otherwise is to engage the mystical position that the polygraph measures lies per se.
We have plenty of evidence that the polygraph doesn't measure lies and doesn't measure emotion.
In its simplest form, the ploygraph, like every other test, is just a matter of stimulus and response. We present the stimulus - in the form of a question - and measure the response. We do that several times, becuase it is a basic principle of all measurement-based sciences that measurements are themselves estimates, and a more stable estimate can be obtained by aggregating together several measurements. Measure-twice-cut-once.
The confusion arises when we engage in reductionistic or simplistic assumptions about the basis of the observed or measured response to a stimulus. In polygraph the stimulus is verbal, is interpreted psychologically, and manifested physiologically. "Psychologically" is a broad term that refers to the complete range of psychological phenomena.
To make this tangible and managable, pychologists commonly talk about three basic things: behavior (because that is always the most reliable expression of anything), emotion (which is a complex rabit-hole to jump down), and cognition (a bit more describable than emotion, and involving attention, memory, and jugement/problem solving), and behavioral learning (involving things like habits, skills, and conditioned responses).
Dialectical-behavioral and cognitive-behavioral psychologists and counselors will generally assume that behavior is mediated by emotion, which is regulated by cognition. This framework assumes a degree of volitional control over the process, and is not intended to be taken concretely in lieu of what we know about biochemistry and chronic mental health conditions. It's just the most useful way of organizing it for pragmatic purposes.
So, we have coginition, emotion and behavioral conditioning - all three powerful and well established realms of psychology. None of them alone is sufficient to explain human behavior or polygraph responses. What we need is an integrative framework that is consistent with all three psychological paradigms. It would be a serious mistake to continue to put all our eggs in the emotion basket and continue to disregard the wealth of information available to us from the rest of psychology.
All good polygraph questions are some version of "did you do it," where "it" describes the examinee's behavioral involvement in an issue of concern (either a known issue, or an unknown issue). This translates to "are you going to react to this stimulus when I present it during the test."
Remember that the basis of response includes cognition, emotion, and behavioral conditioning.
In cognitive terms, "did you do it?" is the same as "are you going to think about and remember the details of this crime, when I preset this stimulus during the test?" A person who says "no" has expressed that they have no explicit knowledge of the details of the issue, no memory of detail to recollect. A person who says "yes," when asked "did you do it," is expressing that they expect to react to the stimulus, because they will recollect and think specific detail when presented with a stimulus question that describes his involvement in the incident in which he has now informed us of his involvment. In other words, the person who did it might be expected to continue to react to the stimlulus even when answering 'yes.' Not due to emotion, but due to cognition, including the attention to and recollection of specific detail.
In emotional terms, we have historically said something to the effect that polygraph measures fear of detection. In reality, our pnuemo tubes probably cannot tell one emotion from another, only that some strong emotion is ocurring. So, "did you do it," in emotional terms, translates to "are you going to have any strong emotional reactions when I present this stimulus during the test." When a person says "yes," it might be assumed that they have emotion about the event or the potential consequences, but we really don't know which. If we assume the polygraph measures fear of detection, then we have to control the examinee's emotions (as if that's possible) to ensure they direct their emotional focus to the issue of whether or not they are lying. This is what gets us looking like silly meat-heads to our detractors - the assumption that we have to, or can, control someone else's emotions in order to make the polygraph work. It is our assumption that a person who was not involved should have no particular fear, or other strong emotion, because they won't get punished. In reality, it is possible that a truthful person, subject to an investigation, might still have some strong emotion about a matter - we don't know, because we can't yet actually read anyone's mind. What we know is that the person who says "yes" is telling us they might have some emotional reaction to the stimulus.
In terms of behavioral-conditioning, "did you do it," translates to "did you eat any meat-power associated with this stimulus," or "are you going to salivate when I ring this stimlus bell/question during the test." The person who is saying "yes" is telling us they were involved in the issue, and may react to the stimulus when we present it during the test.
Now consider the simple proposition of a person who says "no" to a polygraph question. That examinee is telling us they have no detail or memory to recollect, no particularly strong emotion attached to the stimlulus (other than perhaps annoyed at having to answer polygraph questions), and no behavioral experience which would serve as a conditioning event that would cause them to react physiologically when we ring the bell or ask the question.
Knowing the basis of reaction helps us to better anticipate the strengths and potential limitations of the polygraph.
The best scientific position for us to seek, is one which has a theoretical explanation that has is consistent with knowlege and theory from related sciences (face validity), has a falsifiable hypothesis that can be evaulated with a measurment-based mathematical model (convergent validity), and has experimental evidence to support that it works as expected (empirical validity).
Epistemologically, truth is a property of statements about things or events. Because things like emotion and belief are intangible, they internal or intrinsic experiences that cannot be externally verified. They cannot therefore be falsified. They are unfalsifiable. Statements about emotion and belief cannot therefor be true. However, they can be false or misleading - people can make statements about emotion and belief that are intended to mislead others. So, socially and quoloquially, people may lie about their emotion or beliefs, but statements about emotion and belief cannot be epistemologically true. This may seem counterintuitive, but has to do with the difference between linguistics and logic. Statements about emotion and belief are not scientifically verifiable, because they are not falsifiable. Statements about things and events (behavior) are falsifiable, and therefore can be regarded as consistent with the requirements of science. Polygraph is used to investigate things for which there is no other means of investigating. We justify doing that because we have a scientific basis and scientific approach. The things we investigate are a matter of science as long as they are consistent with the type of things that science can address - even if each single issue or incident cannot be investigated through other means. That is the basis of scientific inference and statistical inference. Tangible things tend to behave predictably. Not perfectly, but predictably. To the extent that we study the problems, establish norms and know what to expect, we can make mathematical predictions or judgements about inclusion in one or another category of optoins - such as truth/deception or involved/not-involved in a behavioral issue.
I will argue that 'yes' answered questions are potentially inferior to 'no' answered questions. That the polygraph is probably a better lie-detector than truth-detector. That confirmatory testing approaches may be problematic.
I don't think this means we should completely get rid of 'yes' answer or confirmatory testing attempts. There may be some high-stakes security or information circumstances that warrant the vetting or investigation of an informant or information source before choosing to rely on some information from the person. This does mean, to me, that most of us should probably be careful with 'yes' answered questions. I'll go so far as to suggest that any question that can't be answered 'no,' should be scrutinized further for the suitability or testability of that particular question target.
.02
r
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"Gentlemen, you can't fight in here. This is the war room."
--(Stanley Kubrick/Peter Sellers - Dr. Strangelove, 1964)
Polygraph Place Bulletin Board
posted 07-06-2009 12:58 PM
