Current FBI Polygraph/Interrogation Practices Put the Actually Innocent at Risk of False Confession Charles R. Honts Boise State University Idaho USA Paper presented at the American Psychology- Law Society Annual Meeting 9 March 2013, Portland, Oregon, USA Copyright 2013, Charles R. Honts & Boise State University 1 Polygraph Tests Polygraphs are now used worldwide. The Innocence Network - the polygraph, false confessions and miscarriages of justice Three possible outcomes of a polygraph examination: Truthful (suspect released) Deceptive (suspect interrogated) Inconclusive (?) 2 Field Practices and Inconclusive Outcomes An inconclusive outcome by definition indicates that insufficient data were present to make an inference about credibility, one would logically assume that people with inconclusive polygraph outcomes would not be interrogated. 3
Field Practices and Inconclusive Outcomes However, recent sworn testimony by an FBI special agent/polygraph examiner indicates that with the FBI an inconclusive outcome is treated the same as a deceptive outcome and the suspect is interrogated. 4 In response to questioning about the fact that 4 independent reviewers found the polygraph he conducted to be inconclusive: They don t operate in the law enforcement world, where even -- for the sake of argument, even the fact that they said that the tests were inconclusive, as far as the FBI is concerned, if a person does not pass the polygraph, we re going to ask them about it. SA Christopher R. Braga (July, 2012) 5 Analysis (IG) analysis, first described by Wells and Lindsay (1980) and expanded by Wells and Olson (2002) uses a Bayesian-based approach to describe the impact of base rates on the information provided by eyewitness identification procedures. 6
IG & the Polygraph Honts & Schweinle (2009) adapted IG analysis to examine polygraph test (comparison question test) outcomes. 7 IG for CQT Field Studies Honts & Schweinle (2009) 0.9 0.8 0.7 0.6 0.5 0.4 IG T IG Inc IOG Dabs 0.3 0.2 0.1 0 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58 61 64 67 70 73 76 79 82 85 88 91 94 97 Base Rate of Guilt 8 Current Federal Data American Polygraph Association (2011) False Positive Rate 13.8% False Negative Rate 3.4% Truthful Subject Inconclusive Rate 25.5% Guilty Subject Inconclusive Rate 3.4% 9
Confidence With Inconclusive Truthful Inc Deceptive Total Innocent 611 255 134 1000 Guilty 34 128 838 1000 Total 645 383 972 2000 Confidence 94.7% 86.2% Confidence Without Inconclusive * The percentage of innocent people subjected to interrogation increases by 190% while the percentage of guilty people interrogated increased by only 15% Truthful Inc Deceptive Total Innocent 611 389* 1000 Guilty 34 966 1000 Total 645 1355 2000 Confidence 94.7% 71.3% 10 for Federal CQTs when no action is taken to an inconclusive outcome. 11 for Federal CQTs when inconclusive are treated as deceptive outcomes. 12
IG Analysis Conclusions With no action to inconclusive outcomes the IG for a deceptive outcome peaks at 0.429 at a base rate of guilt of 29%. When inconclusive outcomes are treated as deceptive outcomes, the IG for a deceptive outcomes peaks at 0.224 at a base rate of guilt of 39%. Effectively the current FBI policy of interrogating persons who produce inconclusive outcomes cuts the IG of a deceptive outcome almost in half. 13 Actual Innocence When a person who is actually innocent takes a polygraph from a high authority source like the FBI, and is then told that they are deceptive and that the polygraph is 100% accurate (overstating the accuracy of the polygraph is a common practice when beginning an interrogation) the polygraph serves as a powerful false evidence ploy that seems very likely to increase the number of false confessions. 14 Implications Any policy that increases the number of actually innocent people subjected interrogation and false evidence by 190% with a minimal increase (15%) in interrogating the actually guilty would seem to be strongly against the public interest. If the FBI policy is widespread within general law enforcement, then thousands of innocent people in the U. S. are needlessly being subject to interrogation each year at a risk of many false confessions. 15