Unmasking Deception: A Global Analysis of Forensic Psychology and the Legal Limits of Deception Detection Techniques

Mr. Saurabh Tiwari
DOI:

Abstract

This paper critically examines deception detection techniques (DDTs), i.e., polygraph tests, brain mapping, and narco-analysis by analyzing their scientific foundation and legal admissibility across jurisdictions. The research explores the historical evolution of forensic psychology, tracing developments in deception detection from traditional interrogation to modern neuroscience-based evaluations. It evaluates key forensic principles used in criminal trials and their evidentiary significance. The study employs a comparative legal methodology, examining admissibility frameworks in India, the USA, the UK, and Singapore, highlighting jurisdictional variations in forensic reliance. In India, landmark cases like Selvi v. State of Karnataka affirm that involuntary administration of DDTs violates fundamental rights under Articles 20(3) and 21 of the Constitution. In contrast, countries like the USA impose stringent scientific reliability standards, rejecting polygraph results as inadmissible. The UK and Singapore adopt a more case-specific approach, allowing forensic psychological tests under regulated procedural safeguards. Findings reveal ethical and constitutional challenges in forensic deception detection, questioning the credibility and voluntariness of confessions obtained through such techniques. The study identifies gaps in forensic regulation and calls for standardized protocols, judicial oversight, and enhanced forensic infrastructure. It recommends scientific validation of DDTs to improve legal applicability while balancing forensic innovation with privacy and self-incrimination rights. Ultimately, this research advocates judicial reform and interdisciplinary collaboration to optimize forensic psychology’s role in criminal investigations while ensuring compliance with human rights standards.

Keywords

Forensic Psychology, Deception Detection Techniques (DDTs), Narco-Analysis, Legal Admissibility of Evidence, Comparative Criminal Justice, Human Rights and Self-Incrimination, Judicial Oversight and Forensic Regulation