Polygraph tests in the legal system | Legal use of polygraph in justice

Polygraph testing in the legal, justice system

Lie detector use in justice system | Polygraph legal frame

The legal system use of polygraph tests has caused controversy since its very first intent. Peer review and lack of scientific foundation were the main objections when first denied in the case United States vs. Frye in 1921. A century has passed but this first case still serves as the guideline for popular perception “Polygraph is not accepted in court”.

This, however, is far from true and polygraph test reports have made their incursion in justice systems all around the world to help improve the fairness of legal processes.

Polygraph tests in the legal system, past, present, and future

The first known intent to introduce lie detection evaluation in a legal process is William Marston’s, discontinued blood pressure test performed on Frye in California, United States.

A lot has happened ever since. Technology has evolved, human rights strengthen and the justice system expanded its scope in society.

When we talk about the legal system we have to understand that the term is used broadly. Too many variables exist to oversimplify this concept. Just take into account the following variables:

Legal systems: Common law, Civil law, Religious law
Regulated frameworks: Sports laws, Trade treaties, etc.
Legal frameworks: Criminal law, Civil law, Administrative law, Military law, labor law
Branches of Justice: Law enforcement, Judiciary, Corrections
Human factor: Progressive/conservative judges, religious leaning judges, Etc.

There are just too many variables to oversimplify the legal system. Thus apply the same line of thinking to polygraph equals to a lack of understanding of the legal process.

The truth is that polygraph test reports are used in tribunals on a daily basis, not only in the United States but around the world.

It is true that this fact has not yet made it to a broad public, even lawyers, attorneys are not well informed about the applications of this profession. Nevertheless, little by little it has gained ground and it will only continue to increase in the future.

Who uses lie detection tests in legal procedures?

Like mentioned before there are just too many variables to give a simple answer to this question. We will ry to give an idea how polygraph is used in the process of delivering or making justice.

We can divide the process into three parts:

Pre-trial
Trial
Post-trial

Let´s just take these phases as a starting point and try to give examples how forensic psychophysiology is applied.

1. Pre-trial:

In the investigation phase, the polygraph can be used to help further the investigation, helping to build a case. Suspects can be asked to undergo a lie detection test. Police will be the main user the of this instrument at this stage, although defense attorneys can also ask their client to submit to a test to have charges dropped.

2. Trial:

When parts agree to use the polygraph, the outcome might be accepted by a judge. Defendants also can present a forensic psychophysiology report to defend their case. Most judges will take into consideration a professional and well-founded report.

3. Post-trial:

After being condemned, detainees might be offered the possibility to spend part of their time in supervised liberty. A popular application is post conviction sex offender treatment polygraph programs. Convicted sex offenders are offered to spend the rest of their sentence on parole under the condition they follow psychological treatment that includes periodical polygraph maintenance and monitoring tests.

Polygraph tests for defendants

Defendants can also use polygraph tests to help their case. Often polygraph is thought to be used only by police, intelligence agencies, law enforcement, etc. However, with the expansion of private polygraph examiners, defendants have also gained access to this tool. If it can be used to accuse but it can also be used to prove innocence. Therefore, more and more defendants use forensic polygraph test reports to defend their case in tribunals.