EvidenceProf Blog

Editor: Colin Miller
Univ. of South Carolina School of Law

Wednesday, November 7, 2012

White Coat Syndrome Squared: What Can White Coat Syndrome Tell Us About Polygraph Exams & Ecological Validity?

There are two different uses of the phrase "white coat syndrome." One has explicity been tied to expert evidence.

In the 1990s, legal professionals blamed the "white coat syndrome" for having an impact on juries that was strikingly similar to the CSI effect. "White coat syndrome" is the term used to describe a phenomenon where "jurors mechanistically defer to certain experts because of their field of expertise." (Neil Vidmar, Expert Evidence, the Adversary System, and the Jury, 95 AM. J. PUB. HEALTH S-37-S143, S138 (July 2005)....However, numerous studies demonstrate that jurors do an exceptional job of focusing on the evidence, as opposed to the expert, and do not automatically adopt expert opinions as their own. These studies demonstrate that "jurors are far more skeptical and demanding in their assessments [of expert testimony]" and that "[they] attempt to evaluate the testimony on its merits rather than deferring to an expert's credentials, likeability, or other peripheral factors."

So, do jurors actually defer to certain experts, and do they defer to polygraph experts? I don't know, but courts consistently rely upon this rationale to deem polygraph evidence inadmissible. As noted in my post yesterday, one of the reasons that Texas courts deem polygraph evidence inadmissible is based upon the concern that jurors overvalue polygraph results.

This post, however, deals with the second use of the phrase "white coat syndrome."

As noted in Fields v. Commissioner of Social Sec., 2012 WL 4792916 (S.D.Ohio 2012),

"White coat syndrome" is a condition wherein the individual demonstrates elevated blood pressure in a clinical setting, and not in other settings, due to anxiety and apprehension about visiting the clinic. http://www.whitecoatsyndrome.org/.

Now, what relevance does this have to polygraph evidence? As noted in Veazey v. Communications & Cable of Chicago, Inc., 194 F.3d 850 (7th Cir. 1999),

The standard polygraph has three components: a blood pressure cuff, a galvanic skin response indicator, and a pneumatic chest tube. The blood pressure cuff is attached to a person's upper arm to record changes in blood pressure. The galvanic skin response indicator measures changes in the skin's electrical conductivity, which increases when a person perspires. It consists of two electrodes which are attached to the index and second fingers of one hand. The pneumatic chest tube is strapped around the chest to measure alterations in breathing patterns. Other components can be added to the standard polygraph. Some polygraphs include a pneumatic tube which is stretched around a person's throat to gauge swallowing, contractions of the throat, and voice muscle tension. The more "sophisticated" polygraphs may also be connected to chairs which have seats and armrests wired to monitor muscle pressure and body movements.

So, one of the key components of a polygraph exam is blood pressure. As I noted a few days ago, the problem with most (all?) of the polygraph studies showing that polygraph exams have a high accuracy rate is that they lack ecological validity. As I noted in my prior post,

Based upon the way that polygraph exams work, you can see why most polygraph studies lack ecological validity. Many of these studies are done on college (psychology) students with nothing or at most a few bucks at stake. Such a study might conclude that polygraphs are 87%, 90%, or even 95% accurate. But what does this tell us about the accuracy of polygraph exams on criminal defendants?

These defendants are often subjected to pretrial incarceration. They often have limited resources. They frequently have an overburdened and inexperienced public defender. Their liberty is often at stake. Their life is sometimes at stake. Etc., etc. It is easy to see why there are few false positives when carefree college students are tested. But what about jittery criminal defendants with everything to lose? (And what about sociopathic criminal defendants who are among the 5-10% generally recognized as untestable?).

Now, what does white coat syndrome tell us about criminal defendants? My argument is that it tells us that there is likely to be a significantly higher false positive rate among criminal defendants than research subjects. Here is some relevant commentary:

•The polygraph is effective in getting suspects to confess. The test is inherently stressful, and polygraph examiners are generally trained, experienced interrogators....In field studies, "confessions are most often obtained by polygraphers after a subject has failed the polygraph test." Major Scott E. Reid, Military Rule of Evidence 707 and the Art of Post-Polygraph Interrogation: A Proposed Amendment to the Blanket Exclusionary Rule, 2001-NOV Army Law. 1, 5 n.16 (2001); and

•"Furthermore, polygraph examinations are often highly stressful for the subject because, through this interrogation technique, both the innocent and the guilty are thus 'informed' that the polygraph indicates they are liars who have committed illegal acts." Julia K. Craig, Note, The Presidential Polygraph Order and the Fourth Amendment: Subjecting Federal Employees to Warantless Searches, 69 Cornell L. Rev. 896, 904 (1984).

In other words, based upon the stressful environment of a polygraph exam, we might expect the blood pressure of a criminal suspect to be elevated regardless of whether he is lying. Conversely, we wouldn't necessarily expect such an elevation from a college student taking part in a polygraph study who has no skin in the game.

Now, you may ask, "What about baseline questioning?" If my theory is correct about the blood pressure of a criminal suspect being elevated during a polygraph exam is correct, wouldn't that it also be reflected in the baseline questioning conducted during an exam wherein the examiner asks the suspect questions with known answers to establish a baseline reading of physiological responses? And wouldn't that mean that we would still achieve relative accuracy becauase we are comparing elevated reading #1 (baseline reading) against elevated reading #2 (reading after answers to questions related to the crime?

I don't think so. Why. Well, look at the way that courts treat routine booking questions. They treat these as benign questions that don't trigger Fifth Amendment scrutiny or the Miranda warnings. This is to be contrasted with custodial interrogation, which is "inherently coercive" and increasingly stressful as it proceeds. Wouldn't the same reasoning apply to polygraph exams. Sure, a suspect is likely somewhat stressed when answering baseline questions during a polygraph exam, but that's an entirely different ballgame than when he is being asked questions about the crime charged by an experienced interrogator.



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