Use of Neuroscience in Criminal Law Doctrine
and Criminal Sentencing
Authors: Polubinskaya Svetlana V. 
Published: December 2019

Modern neuroscience has long expanded beyond the framework of
traditional biological and medical sciences that study the central nervous system and human brain. Nowadays researchers aim at exploring the links between the biological processes in the brain and human behavior. There is a growing number of research on social neuroscience investigating the neural basis of social behavior. The progress
of such studies is facilitated by application of non-invasive neuroimaging techniques (magnetic resonance imaging, functional magnetic resonance imaging, positron emission tomography, etc.), which provide the data on brain structure and activity in the form of visual images.
The task of criminal law is to conceptualize the results of brain studies used as evidence in criminal courts in a number of countries that have also revived discussions about free will and criminal responsibility.
According to foreign authors, neurobiological evidence, including the results of brain imaging, is used in courts at various stages of the process, in particular when
determining the defendant’s competency to stand trial and in insanity defense.
However, more often they appear in criminal cases of serious violent and sexual crimes in order to confirm the diagnosis of a mental or neurological disorder and/
or brain damage of the defendant and thereby justify the mitigation of punishment.
Such evidence is often combined with results of other expert examinations and
appear to be a part of a wider picture describing the defendant.
International studies also show that the courts are cautious in decisions concerning
admissibility of brain scan evidence because of uncertainty about its
scientific validity, reliability and relevance to the case. Moreover, the very practice
of the presence of such evidence in courts is considered as ambiguous. The opponents refer to insufficient validity and reliability of such evidence and the subjectivity of experts while interpreting the results of brain imaging. There are also problems of reliability of expert conclusions when the group data is applied to the
individual case considered in court. The opponents also refer to the complexity and interconnectedness of the human brain, the inability to link complex human behavior
to a specific brain area not to mention a causal relationship between specific brain area and specific behavior.
The progress of neuroscience has also given an impulse to a new wave of
discussions on key issues of legal philosophy and criminal law doctrine. The results
of some studies are interpreted as evidence on lack of voluntary nature of human
actions and the illusion of free will, since the brain sends a signal to act before a person realizes it. In combination with findings concerning links between specific
brain structures and aggression, impulsiveness and the ability to control one’s
behavior, these data are used as the ground to justify the revision of traditional
doctrinal ideas about guilt and criminal responsibility.
However, majority of experts who analyze the use of the results of neurobiological
studies in criminal law doctrine and practice disagree with these claims. They
acknowledge that such research can contribute to a better understanding of the
mechanisms of human behavior and influence the doctrinal understanding of legal
categories, such as guilt and insanity, but they do object against identification of the
mind with the brain. The concepts of free will and responsibility are social constructs,
and neurosciences are not able to convince society to abandon them.