From the Guidelines
Physiological biomarkers like heart rate variability (HRV) and functional magnetic resonance imaging (fMRI) cannot reliably detect "true criminals." While these technologies can measure physiological responses during questioning or when viewing certain stimuli, they cannot definitively determine criminal intent or identify someone as a criminal. Current research shows these methods have significant limitations in real-world applications. HRV can indicate stress responses but cannot distinguish between stress caused by guilt, fear of false accusation, or general anxiety, as seen in studies on fear-induced bradycardia and safety learning 1. Similarly, fMRI can show brain activity patterns during deception, but these patterns vary considerably between individuals and contexts, leading to both false positives and negatives. Additionally, these technologies face ethical concerns regarding privacy, consent, and potential misuse in legal settings, as highlighted in discussions on the use of brain imaging tests for chronic pain 1. The complex nature of criminal behavior involves social, psychological, and environmental factors that cannot be reduced to physiological measurements alone. Legal systems worldwide generally do not accept these methods as reliable evidence precisely because they lack sufficient scientific validation for determining criminal identity or guilt. Some studies focus on the use of biomarkers in different contexts, such as managing workload in athletes 1, but these do not directly apply to the detection of criminal behavior. Therefore, relying on physiological biomarkers for criminal detection is not supported by current scientific evidence and raises significant ethical and legal concerns.
From the Research
Physiological Biomarkers in Detecting True Criminals
- The use of physiological biomarkers, such as heart rate variability (HRV) and functional magnetic resonance imaging (fMRI), has been explored in detecting deception and potentially identifying true criminals 2, 3.
- A study published in 2016 found that fMRI experts were 24% more likely to detect concealed information than polygraphy experts, suggesting that fMRI may be a potential alternative to polygraphy in lie detection 2.
- Another study from 2009 investigated the use of electrodermal activity (EDA) in conjunction with fMRI to detect deception, but found that adding EDA did not improve the accuracy of fMRI detection in a laboratory-based deception task 3.
- However, a more recent study from 2020 proposed novel indices of phasic autonomic regulation mechanisms by combining HRV and EDA correlates, and demonstrated significant statistical differences between the cold-pressor elicitation and previous resting state, as well as an accuracy of 73.08% for automatic emotional valence recognition 4.
- The development and validation of forensic assessment instruments (FAIs) have also advanced the field of forensic psychology, providing specialized measures for addressing psycholegal standards and forensically relevant issues 5.
- Public attitudes toward legally coerced biological treatments of criminals have also been explored, with findings suggesting that the public is relatively sanguine about coercive offers of biological agents, as well as changing the personality of criminals 6.
Key Findings
- fMRI may be a potential alternative to polygraphy in lie detection 2.
- Combining HRV and EDA correlates can provide novel insights on autonomic functioning and improve accuracy in detecting emotional valence 4.
- FAIs have been developed and validated to address psycholegal standards and forensically relevant issues 5.
- Public attitudes toward biological treatments of criminals are influenced by concerns regarding safety and coercive nature of the treatment 6.