System for and method of detecting polygraph countermeasures

• US 6,757,559 B2
• Filed: 01/09/2002
• Issued: 06/29/2004
• Est. Priority Date: 01/10/2001
• Status: Expired due to Fees

• Current Assignee: Amitronix Inc.
• Original Assignee: Amitronix Inc.
• Inventors: Cohen, Emmanuel
• Primary Examiner(s): Jones, Mary Beth
• Assistant Examiner(s): Szmal, Brian Scott
• Application Number:
  US10/040,760
• Publication Number:
  US 20020091336A1
• Time in Patent Office: 902 Days
• Field of Search: 600/547, 600/300, 600/544, 600/545, 600/510, 600/523, 346/33.R, 346/13, 324/76.13
• US Class Current: 600/547
• CPC Class Codes: A61B 5/0533 Measuring galvanic skin response
• CPC Class Codes: A61B 5/164 Lie detection

Abstract

A system for, and method of identifying a use of countermeasures by a subject of a polygraph test, the method including the steps of: (a) posing a plurality of questions to the subject; (b) determining, for each question, a time interval between an end of the question and a start of an answer by the subject to the question, thereby generating a plurality of time intervals, and (c) comparing the time intervals to identify the countermeasures.

Claims

1. A method for identifying a use of countermeasures by a subject of a polygraph test, the method comprising the steps of:

(a) posing a plurality of control questions to the subject;

(b) posing a plurality of relevant questions to the subject;

(c) determining, for each question of said controlling questions and said relevant questions, a rime interval between an end of said question and a start of an answer by the subject to said question, thereby generating a plurality of control question time intervals and a plurality of relevant question time intervals, and

(d) comparing said control question time intervals to said relevant question time intervals of the subject, so as to identify the countermeasures.

2. The method of claim 1, further comprising the step of:

(e) monitoring at least one involuntary physiological response of the subject.

3. The method of claim 1, further comprising the step of:

(d) displaying sound waves of said answer.

4. The method of claim 1, wherein said posing of said control questions and said relevant questions transpires during the polygraph test.

5. The method of claim 1, wherein said answer is a sound response.

6. The method of claim 1, further comprising the step of:

(e) recording a sound recording of said each question and said answer.

7. The method of claim 1, wherein, in said comparing of said time intervals, X_C represents an average of said time intervals pertaining to said control questions, and X_R represents art average of said time intervals pertaining to said relevant questions, and wherein the use of countermeasures by the subject is indicated when a difference between X_C and X_R exceeds a pre-determined value.

8. The method of claim 1, wherein, in said comparing of said time intervals, X_C represents an average of said time intervals pertaining to said control questions, X_R represents an average of said time intervals pertaining to said relevant questions, and δ

₁ and δ

₂ are pre-determined values, and wherein the use of countermeasures by the subject is indicated when X_R−

X_C>

δ

₁ or when X_C−

X_R>

δ

₂.

9. The method of claim 1, wherein, in said comparing of said time intervals, X_C represents an average of said time intervals pertaining to said control questions, and X_R represents an average of said time intervals pertaining to said relevant questions, and wherein No Deception indicated (NDI) is concluded when a difference between X_C and X_R is below a pre-determined value.

10. A system for detecting a use of countermeasures by a subject of a polygraph test, the system comprising:

(a) a polygraph instrument for recording at least one involuntary physiological activity of the subject;

(b) a sound-recording device for recording audio data during the polygraph test;

(c) a time-measuring device for producing time information, and

(d) a processing unit operatively connected to said sound-recording device and to said time-measuring device,

wherein said processing unit is designed and configured to utilize said time information and said audio data so as to;

(i) calculate for each question of a plurality of questions, a physiological response time between a time associated with said question and a change in said physiological activity, thereby generating a plurality of said physiological response times, and

(ii) process said physiological response times to identify the countermeasures.

11. The system of claim 10, wherein said at least one involuntary physiological activity is monitored using a galvanic skin response (GSR).

12. The system of claim 10, wherein said change in said physiological activity corresponds to a minimum value adjacent to a galvanic skin response peak to said question.

13. The system of claim 10, wherein said time associated with said question is a beginning of said question.

14. The system of claim 10, wherein said plurality of questions includes a plurality of control questions a plurality of relevant questions, and wherein said plurality of physiological response times includes a plurality of control question physiological response times and a plurality of relevant question physiological response times.

15. The system of claim 14, wherein said processing unit is designed and configured to compare said control question physiological response times and a said relevant question physiological response times to identify the countermeasures.

16. The system of claim 15, wherein said time associated with said question is a beginning of said question.

17. The system of claim 15, wherein said at least one involuntary physiological activity is monitored using a galvanic skin response (GSR).

18. The system of claim 15, wherein said change in said physiological activity corresponds value adjacent to a response peak of said physiological activity.

19. The system of claim 18, wherein said physiological activity is monitored using a galvanic skin response (GSR).