Convicting someone of a crime depends in part on the mental state of the criminal. We make a distinction between knowing criminality and recklessness, and we give the two states of mind different levels of legal culpability. In the courtroom, however, assessing these mental states and a criminal’s past intentions can be extremely challenging.

However, neuroscience may soon give us hints about what’s going on internally as criminals knowingly committed their crimes. A recent study published in PNAS asserts that brain activity is different in people who know they are committing a crime, and that activity can be used to distinguish them from people who commit crimes recklessly (no, this is not science fiction). If the data is sound, this study seems to suggest that brain imaging could determine a criminal’s mindset—but only if the imaging is performed while the crime is being committed.

To conduct this study, the authors in PNAS performed brain imaging with human subjects and then analyzed the data using a machine-learning algorithm. Brain-imaging study participants were placed in an fMRI machine and presented with a scenario in which they mentally role-played carrying a suitcase through a guarded checkpoint. This mental role-play was accompanied by images on a screen within the MRI tube.