PoliceCarrying Tasers increases police use of force

Published 4 January 2019

Cambridge University experiment with City of London police found that, while rarely deployed, just the presence of electroshock devices led to greater overall hostility in police-public interactions – an example of what researchers call the “weapons effect.”

A new study has found that London police officers visibly armed with electroshock ‘Taser’ weapons used force 48 percent more often, and were more likely to be assaulted, than those on unarmed shifts.

However, while use of force can include everything from restraint and handcuffing to CS spray, the Tasers themselves were only fired twice during the year-long study period.  

Criminologists from the University of Cambridge say the findings suggest that Tasers can trigger the “weapons effect”: a psychological phenomenon in which sight of a weapon increases aggressive behaviour.  

While the ‘weapons effect’ has been repeatedly demonstrated in simulated conditions over the last forty years, this is one of the largest studies to show it “in the field” and the first to reveal the effect in law enforcement.

Researchers say their findings, published today in the journal a , may well apply to policing situations in which other forms of weaponry – including the lethal variety – are involved. 

“We found that officers are more likely to be assaulted when carrying electroshock weaponry, and more likely to apply force,” said lead researcher Dr Barak Ariel from Cambridge’s Institute of Criminology.

“It is well established that the visual cue of a weapon can stimulate aggression. While our research does not pierce the ‘black box’ of decision-making, the only difference between our two study conditions was the presence of a Taser device.”

“There was no increase in injury of suspects or complaints, suggesting it was not the police instigating hostilities. The presence of Tasers appears to provoke a pattern where suspects become more aggressive toward officers, who in turn respond more forcefully,” he said. 

The City of London force is responsible for policing the “Square Mile” business district in the centre of London. It also holds national responsibility for economic crime and prioritises counter-terrorism, violent crime and public order due to its central location.

The force was the first in England and Wales to test “extended deployment” of Tasers – described as “conducted energy devices” in UK policing – to frontline officers. During the rollout, police chiefs allowed Ariel and colleagues to conduct a major experiment.