Scanning a defendant’s brain can establish mens rea, claim neuroscientists

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Will the results be used in the courtroom?

A group of top neuroscientists is claiming that the mens rea of a crime could be established by scanning a defendant’s brain.

Cue the terrible flashbacks to criminal law lectures: Latin for “guilty mind,” the mens rea of a criminal offence is its mental element. Different offences carry different levels of mens rea, so the court will sometimes need to consider whether a defendant committed a crime on purpose, through sheer reckless behaviour, accidentally, etc.

Researchers — based both in the United Kingdom and the United States — scanned the brains of 40 volunteers as they took part in a computer-based task that required them to smuggle a suitcase across the border of a country. Offered a reward for doing so, some participants were told that the suitcase contained drugs, while others were not. The computer simulation also varied the risk of the volunteers being stopped and searched at customs.

Brain scan images taken from participants

With the would-be smugglers undergoing brain scans as they carried out the online tests, scientists claim that they were able to establish — with a high-degree of accuracy — which participants were knowingly breaking the law, compared to those who were simply taking a risk.

Commenting on the significance of the research, the paper states:

Because criminal statutes demand it, juries often must assess criminal intent by determining which of two legally defined mental states a defendant was in when committing a crime. For instance, did the defendant know he was carrying drugs, or was he merely aware of a risk that he was? Legal scholars have debated whether that conceptual distinction, drawn by law, mapped meaningfully onto any psychological reality.

But criminal lawyers do not need to panic just yet. Taking a more sceptical view of the research’s implications, anonymous blogger the Secret Barrister told Legal Cheek:

While it’s interesting that there appears to be a neurological distinction between intent and recklessness, it’s doubtful that this will be of any practical significance in the courtroom for juries assessing past events.

There is also one major snagging point. “In most cases, when someone is committing a crime they are not doing so while inside a scanner,” the paper concedes.

Read the research paper in full below:

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