The criminal justice system is plagued by wrongful convictions. There are estimates that 2% to 10% of Americans in prison have been wrongfully convicted. These innocent individuals face incredible challenges when it comes to overturning their convictions. However, advances in forensic technology and investigative techniques have emerged as valuable tools for the wrongly convicted to prove their innocence.
Polygraphs measure changes in physiological responses as a means of detecting deception. Components of polygraphs include:
- Pneumographs – measure thoracic and abdominal breathing patterns
- Electrodermal – gauge changes in skin electrical conductivity
- Cardiographs – record cardiovascular activity
During polygraph examinations, examinees respond to questions while connected to the machine. Deceptive or dishonest responses tend to produce measurable physiological reactions. Polygraphers then analyze the results to determine if fraud has occurred.
While polygraphy has faced criticism regarding its accuracy and reliability, when administered by a skilled examiner under controlled conditions, its accuracy rate exceeds 90 percent. As such, polygraphs remain widely used in criminal investigations, employee screenings, and national security assessments.
Polygraphs for the wrongly convicted
In recent years, polygraphs have emerged as important tools for the wrongfully convicted to assert and potentially prove their innocence. lie detector test offers several key benefits:
- Provides Objective Evidence – Unlike personal testimony that can be disputed, polygraphs offer quantifiable physiological data to evaluate claims of innocence. Findings supporting truthfulness powerful corroboration.
- Assess Credibility – Polygraphs allow examiners to gauge the overall credibility of individuals claiming wrongful convictions. Testing reveals if their accounts seem truthful and consistent.
- Generate Leads – Exams elicit new information or details that point to alternative suspects or uncover flaws in the original investigation. These leads aid appeals or new investigations.
- Motivate Confessions – If confronted with results indicating deception, the real perpetrator must confess, ultimately exonerating the innocent.
While polygraphs show promise in aiding the wrongly convicted, the technique has limitations:
- No universally accepted accuracy rate – Reliability estimates vary widely among researchers and critics.
- Susceptible to countermeasures – Physical movements, drugs, or mental tricks alter results.
- Requires experienced examiners – The usefulness relies heavily on the examiner’s skills in questioning techniques and analyzing responses.
- Not universally admissible in court – Some jurisdictions prohibit polygraph evidence or view it as unreliable.
- Potential for false positives – They indicate deception in truthful individuals under highly anxiety-provoking testing situations.
For these reasons, polygraph results are typically not sufficient on their own to overturn convictions. Rather, findings ideally corroborate other evidence of innocence. Experts recommend polygraphs be used selectively on the wrongly convicted as one component of a comprehensive investigative and legal strategy.