NEUROSCIENCE AND EVIDENCE

INTRODUCTION

New technologies not only play a part in the field of evidence law as mechanisms for re-creating reality that can serve to convince the trier of fact, but are also presented as a means capable of verifying traditional forms of evidence.

We put forward for consideration here whether it is possible to check, via technology, the testimony of parties, witnesses, and experts. Neurological science appears to offer mechanisms capable of measuring the veracity of such statements such as through magnetic resonance imaging (MRI). However, it is the case that, at present, there is no unanimous consensus regarding the effectiveness or scientific validity of these mechanisms.

Every day, neuroscience provides new techniques aimed at detecting evidence of neural changes in the human brain with the aid of sophisticated brain-imaging techniques that allow us to show specific areas of the brain that execute specific functions. Nevertheless, at present, we face important empirical limitations regarding the dependability of this scientific lie-detection evidence. Even if it were true that it is possible to detect which area of the brain has the function of responding to an interrogation (i.e., to determine scientifically when the speaker is consciously being untruthful), this raises numerous questions, as it is possible that the speaker:

• (a) is lying but has the – innate or acquired – ability to control their emotional reactions, thus preventing the activation of the area of the brain responsible for lying, and the lie is therefore undetected;

• (b) is not lying, but the area of the brain stimulated by lying becomes active because their nervous system has been excessively altered as a result of discussing matters of an intimate nature, or which they have kept secret for some time and wishes to continue doing so, or that could result in particularly damaging consequences of whatever sort (affective, personal, professional, economic, etc.);

• (c) is both lying and telling the truth because, for example, the lie is based on an erroneous knowledge of the facts;

• (d) is telling the truth in relation to facts that formally appear to be false.