Whether you believe polygraph examinations are rooted in the science of measuring human physiology or in "black magic" trickery perpetrated by sophisticated operators, there's no denying that polygraphs have come a long way over the past decade. Since the early '90s, polygraph technology has evolved from the old style ink-and-paper polygraph machines with their easily clogged pens to computerized solutions that can record, store, and analyze physiological data collected during a polygraph examination.
Polygraph exams are controversial. But controversial or not they are a useful law enforcement tool, and I'm never one to toss one of my best tools, especially one that can be as versatile as a polygraph.
The state of the art of contemporary polygraphs is the digital polygraph system, and one of the leading developers and manufacturers of this technology is Lafayette Instruments. Indiana-based Lafayette is the maker of the widely used LX-4000 computer polygraph system.
Consisting of Lafayette's LX 9.5 software, sensors, and a Windows platform portable or desktop computer, the LX-4000 computer polygraph system can do everything that the old pen-and-ink machines could do and much, much more. The LX-4000 can capture seven channels of data, including respiratory, cardio, and galvanic skin response readings.
The heart of the LX-4000 is the LX software, and the latest version, 9.5, is an excellent upgrade of what was already a powerful tool for polygraph examiners. Not only does this software facilitate polygraph examinations, its newest features include the ability to integrate audio and video tracks right into the chart. So besides getting the interpretation from your trained examiner, you'll be able to hear the subject's inflections and see his or her body language right on the computer screen.
To operate the latest version of the LX-4000 system and LX 9.5, you will need a computer that meets the following minimum requirements:
- 1.0GHz Pentium III or higher with 256MB RAM and a 40GB hard drive
- Windows 98/ME/2000/XP operating system
- An available USB Port for the Data Acquisition System sensors
- Digital sound card required for multimedia capabilities along with a digital video camera for video capture if desired and an external or built-in microphone for recording audio.
Security is one of the key concerns for anyone using a digital polygraph system. You have to be absolutely certain that the files cannot be hacked or altered. That's why the security features in LX 9.5 have been upgraded. Each operator's system can be secured by a user name and password. If you choose not to use the password protection, then security is monitored by the onboard auditing system, which tracks almost every nuance of the software's state and logs it. If someone else logs into your PC and tries to change or alter any important info, his or her access will either be denied or logged.
Another great feature of this software is that it gives the user the ability to choose his or her own setups. LX 9.5 is highly configurable, allowing the user to choose chart colors, printer types, video capture rates and methods, file naming conventions, and keyboard shortcuts.
All polygraphs collect physiological responses to questioning. The LX-4000 system accomplishes this using Lafayette Systems' Data Acquisition Systems (DAS) hardware interface. The sensors gather cardio, respiratory, and galvanic skin response data and import it via a single USB port into the software where it is digitally recorded and displayed in real time.