Treat killing like a disease to slash shootings

Shootings and killings in deprived areas of Chicago and Baltimore have plummeted by between 41 and 73 per cent thanks to a programme that treats violence as if it is an infectious disease.

"Violence gets transmitted the same way as other communicable diseases, so we train 'violence interruptors' to prevent escalation," says Gary Slutkin, founder and executive director of CeaseFire.

"They change the norm from 'violence is what's expected of me' to 'violence will make me look stupid'," says Slutkin.

"People believe that boys are doomed to be aggressive, especially males of colour and poverty, and that's how boys must settle disputes," says Pollack. "But we now know it's the socialisation experience that creates this expectation, nurture rather than nature."

The CeaseFire model changes these social norms and behaviour," adds Pollack. "It's a scientifically based programme that works."