In terms of history, the implementation of the polygraph machine is actually quite a recent development in the quest to detect deception. However, the search to find ways of determining if a person is being honest or lying is an age old pursuit.
People have always lied and this has been a means of survival for some, an ability that has evolved. Lying is not even restricted to the human species with animals and all kinds of creatures, even plant life, using means of deception to attract prey or mates or protect themselves from attack.
Human beings are complex and the need to lie can arise from a wide variety of reasons; from self defence to achieving your own agenda and goals to protecting others from harm. Lies are used in professional and personal capacities and are an everyday part of human life. Sometimes these are “white lies” and can be left well alone to make life or information easier to process or to make something more palatable or appropriate for a person to hear. Other lies are less well-intentioned and can cause harm or damage if left uncovered. These are the lies that polygraph has sought to uncover and to establish the truth for those who need it.
History of lying
In very early and ancient traditions there was a belief that goodness could be distinguished from evil simply based on the premise that good was stronger than evil and that godly actions would not enable bad to prevail; honesty was associated with good and dishonesty associated with evil.
Another ancient procedure for the detection of dishonesty was the observation of behaviour. Tests were set for suspected liars to see how they would respond, with their behaviours then being assessed as indicative of truth or dishonesty. This is not a world away from today’s observation of body language which forms part of any comprehensive polygraph examination. However, it was not applied with the level of learning and research that accompanies today’s understanding of body language and often placed the suspect in heavily emotive or pressurised situations that would impact on the individual’s ability to act rationally and in their normal way.
In the second century BC we see the beginnings of the use of physiological or bodily changes to detect deception with the measurement of the pulse being used to determine if someone was lying or hiding information. There are ancient tales from across the world of a person’s pulse being taken to determine the true object of their love and affections, the heart deemed to quicken when this person was mentioned or discussed.
It was not until the nineteenth century that mechanical apparatus started to be implemented for the use of lie detection. Initially, single bodily changes were recorded and used to determine the presence of deception, but this developed into the recording and combining of information received from several different physiological responses and this was the beginning of lie detection testing as we know it today.
Modern-day lie detector history
The use of several combined indicators of deception was initially the brainchild of a Harvard Psychologist, Munsterberg, in 1908. The first report of the practical use of this model of utilising the recording of several different physiological changes within lie detector testing was by Larson in 1921. Larson developed instrumentation that recorded respiration, blood pressure and pulse simultaneously. Larson also recommended the use of questions requiring only yes and no answers the use of a steady and monotone voice to ask these questions.
Lee, a colleague of Larson within a US Police Department, then further refined this model using different methods to record and display data obtained and, also developed techniques used within questioning format to advocate for what is now known as the Peak of Tension approach wherein the subject’s response to the “hot topic” and questions around this is exacerbated by the preceding questions applied.
Keeler, also a colleague of Larson and Lee in the United States of America, then further developed these ideas into his own instrumentation in 1925. Keeler’s model allowed for the recording of all the physiological changes simultaneously as in the instrumentation we see in use today and was also portable and robust adding to its practical applicability. This model was in use until the 1970s when other models exceeded the strengths offered by the Keeler machine.
Current lie detector technology
However, there has been little change in terms of the sensors used since the 1940s and today with the collection of respiratory, cardiac and galvanic skin response being found in contemporary models of polygraph instrumentation still. The major changes have been the computerization of systems to record and analyse data and also the addition of either a sensor or observation of movement by the subject as a further indicator of deception or non-cooperation with testing.
The more significant developments in polygraph testing that have occurred since earlier models are around the techniques used and the questioning format and content and recognition of the importance of this. Reid developed the concept of the probable-lie comparison question in 1947 which is also referred to as the comparison question or control question and this is a technique which is widely used within lie detector testing today. This better allows examiners to achieve a baseline and gauge salience (or significance to the subject) of the “hot” questions when they are asked and therefore to improve the ability these responses offer to identify deception.
Analytic methods for assessing data recorded within polygraph tests were also developed over the mid 1900s with the event of chart scoring being introduced. This allows a system to measure reactions obtained within a lie detector test and made data analysis far more robust than the previous impressionistic methods of decision making employed.
Various different methods of scoring were proposed and there remains a variety of techniques employed today, with different scoring methods being deemed appropriate for the various models of questioning format and whether a test is single or multi-faceted. Computer algorithms were introduced into data analysis and offered several benefits but human input remained integral to the process and research is still ongoing into whether human or algorithmic methods of data interpretation, or the combination of both, are more accurate in deception detection.
There is not a definite inventor of the polygraph test as the test itself consists of many different elements; it is not just a machine but the entire process including instrumentation, preparation, question formatting, data analysis, observation, technique, methodology and decision making. The instrumentation itself as well as the techniques employed have been developed over a long period of time through experimentation, research, studies and learning to refine the overall capacity for lie detector testing to obtain significant and clear recordings and data and to interpret these in the best way to achieve accurate detection of deception.
Research and experimentation is ongoing with new approaches and models such as oculomotor and saccadic eye movement testing apparatus now being employed by some polygraph test providers. This tracks either the movement of the eye (saccades) or eye behaviour (fixation duration, pupil size etc) and such responses or behaviours have been found to indicate fear or attraction. However, questioning is ongoing as to whether this method can act to indicate deception or whether it performs the role of a recognition test more and there has been little research into countermeasures, the potential for manipulation or the effect of blinking, make up, drooping eyelids etc on the effectiveness and accuracy of this model. Further research and understanding is needed before this can be accepted as a true competitor for the polygraph machine.