Although there are many potential fronts on which a criminal defense case can be fought, the primary one is the evidence. Prosecutors are required to demonstrate with relevant and reliable evidence that the defendant is guilty of each charge, beyond a reasonable doubt. When the evidence just doesn’t reach this bar, it isn’t possible to convict. Dealing carefully with evidence, therefore, is a central aspect of an effective criminal defense case.
The type of evidence involved in a criminal case obviously depends on the charges and the circumstances of each case. In certain types of cases, of course, evidence with a scientific basis can make it easier to either prove or disprove charges, depending on which way the evidence goes in the case. One thinks especially of DNA evidence, which can pretty quickly provide definitive evidence in some circumstances. Increasingly, neurobiological evidence is being used in criminal cases as well, by both prosecution and defense.
According to a recent study conducted at Duke University, the number of published judicial opinions mentioning neuroscience evidence increased by more than 200 percent between 2005 and 2012. Legal commentators say that, because most criminal cases don’t go to trial, there are probably a great many more cases in which such evidence was involved.
Many of the cases which make use of neuroscience evidence involve the prospect of capital punishment, but even more—60 percent—involve non-capital cases, including drug trafficking, robbery and fraud. Such evidence has been used, for instance, in ineffective assistance of counsel claim and competency claims. According to researchers, neuroscience evidence is not always influential, but it is estimated to have a positive effect about 20 to 30 percent of the time.
In our next post, we’ll continue looking at the issue of neuroscience evidence and the importance of evidentiary issues when building a strong criminal defense case.