Why police shoot innocent bystanders at times

An "itchy brain" caused by lack of attention rather than an "itchy trigger finger" leads to the killing of innocent bystanders in incidents of shooting by law enforcers, says a study.

Although the research is in its early stages, the results have clear implications for potential use in military and law enforcement settings.

The findings imply that the tendency to squeeze the trigger due to an error not only can be predicted with cognitive tests on law enforcers but also be overcome by training in response inhibition.

"Cognitive tests and training offer some exciting new methods for enhancing shooting abilities, and thereby avoiding some of the most critical shooting errors, such as civilian casualties," said Adam Biggs, visiting scholar at Duke University in the US.

The findings were published online in the journal Psychological Science.

In the new study, 88 young adults played a simulated shooting game. The objective is to shoot armed people as quickly and as accurately as possible, while avoiding unarmed civilians.

After playing, the participants took surveys that assessed their ability to pay attention, signs of motor impulsivity such as finger tapping or restless behaviour, features of autism spectrum disorders and other characteristics.

Individuals also undertook computerised tests of their ability to withhold responses.

The scientists found that the more attention problems a person had, the more likely he or she was to shoot civilians in the simulation.

The study also included some cognitive training to see what might make a difference.

One group underwent training designed to prevent civilian casualties by enhancing response inhibition through a series of computer-based exercises.

The sudden decision to not shoot, called response inhibition, is critical when civilians come into the line of fire.

The other group underwent cognitive training unrelated to the shooting task to show whether any kind of training sessions would make a difference.

The scientists found that people who had completed response inhibition training shot fewer civilians than they did before training. In contrast, the control group's performance was unchanged.