Applying Classical Conditioning Toward the Physiological Detection of Concealed Information: Beyond Native Responses

Applying Classical Conditioning Toward the Physiological Detection of Concealed Information: Beyond Native Responses

Derek C. Tucker 6/8/2005

Psychology today is predominately concerned with phenomena which occur, “on average,” given a particular set of circumstances. Technology, however, is constantly forced to look deeper into phenomena that occur, “on average,” in order to improve the reliability of an instrument for whatever task the technology is to be used. With instruments such as the polygraph, that are applied to assess psychological states of an individual for a specific stimulus, the most technically reliable instrument is functional limited by the accuracy of the underlying psychological constructs for predicting physiological outcomes not “on average,” but “this time.”

While no psychological construct that I’m aware of reports 100% correlation with a specific physiological response, the next best thing is to be able to recognize when an event will likely be part of the average, so that one can modify the expectations for what might occur “this time”. This project investigates the potential of using classical conditioning to increase the reliability of “lie detectors” by using a paradigm that prevents people for whom the test will not work from undergoing critical (or relevant) question judgment (or classification). An issue with deception or lying, however, is that its definition is often subjective. It is imperative that the interrogator and the examinee both agree upon the interpretation of the stimuli used during the investigation. From the perspective of a fly, the Venus Fly Trap is behaving deceptively, though from the plant’s point of view, everything is as it should be. Thus, should a fly be equipped with a polygraph, if it were to ask, “are you a deceiver of flies,” or, “do you contain dangerous chemicals ” would be less effective than, “do you contain chemical X.”

In our society, rather than awaiting natural species adaptation, specialization, and differentiation, the “problem” of deception has been countered by the advance of lie detection techniques. Interestingly, many of these approaches implicitly rely on principles of classical conditioning for the generation and evaluation of results. According to the Committee to Review the Scientific Evidence for the Polygraph (2003), the underlying principle of the polygraph’s function under most paradigms relies on a lifetime of having episodes of intentional deception paired with fear and anxiety. In the parlance of classical conditioning, the unconditioned stimulus would presumably be the fear and anxiety that occur when one is afraid of being caught, while the conditioned stimulus would be the act of lying, or concealing information (Iacono, 2000). The unconditioned and conditioned responses, however, would vary by the individual experience . The original polygraph exam assumed a conditioned fear response as indicated by an increase of blood pressure that occurs on average (Martson, 1938), but as noted in Iacono (2000, p. 775):

“There is no unique physiological response associated with lying, and there is no known physical substrate underlying what these tests measure. In fact, it is not clear what psychological processes are tapped by the techniques employed in polygraphy вЂ" or even how important deception per se is to their outcome. Polygraph operators are taught that their procedures most likely depend on a subject’s fear of the consequences of being detected. However, little research has been directed at this issue; it remains possible that other psychological constructs, such as the guilt and anxiety associated with lying or belief that a test works, are important. Because the psychological underpinnings of applied polygraphy are so poorly understood, it should be no surprise that the physical substrate underlying these techniques has received virtually no attention beyond the level of identifying useful peripheral measures.”

Given the muddy waters of attempting to identify native conditioned responses to intentional deception, this project focuses on the potential to condition reflexive blink responses to statement veracity instead. That is, instead of “asking the plant” if it is a deceiver of flies or contains dangerous chemicals, this project asks whether the plant contains “chemical X,” a question whose answer should not be subjective The traditional polygraph would seek to either force a confession from the Venus Fly Trap during the interrogation, or determine deception based on increased sympathetic nervous system activity that occurred during a denial to a critical question which had been conditioned to occur after a lifetime of being scared when concealing information. The current approach, rather, installs and verifies a blink response contingent on statement veracity (regardless of the behavioral response) such that the outcome of the procedure would be the veracity of a given statement, not the instance of deception.

The Technology in Under Investigation

There are numerous technologies that are applied to the physiological detection of deception (PDD) which are often all combined under the category of “lie detectors.” This categorical title, however, is often a misnomer when applied to the actual function of the devices so named. This label is valid to the extent that if an individual being interrogated by a lie detector fails the exam, they have essentially divulged information which they would have otherwise concealed. This label does not mean that the technology functions by tapping into a cryptic signal specifically emitted during a “lie”. In fact, lie detection techniques vary in the specific measures being recorded, and by the structural design of the interrogation. Indeed, measures from brain waves, vocalizations, cardiovascular changes, and the thermal energy profile of the face have all been applied in efforts to reveal information a person would prefer to conceal.

The wide array of techniques that have been developed does not derive purely from a desire for diversity, but highlights the growing sentiment that new technology can overcome problems in the traditional polygraph. The recent report by the National Research Council on the scientific basis and validity of the polygraph, which also examined related measurement approaches (e.g., voice analysis,