In February 1989, a Correctional Service Canada research brief reached policy makers examining the role of uniforms in federal prisons.

The Stanford Prison Experiment provided a chilling warning. Normal university students placed in guard uniforms quickly turned aggressive and sadistic. They worked to secure compliance by restricting the liberty of their mock prisoners.

Data from policing proved more concrete. In 1969 Menlo Park, California, officers traded military-style uniforms for civilian green blazers. Assaults on officers fell by 30 percent. Citizen injuries from arrests dropped by 50 percent. Turnover crashed from 25.5 percent to just 2 percent.

Canada had tried both extremes. The 1960s Living Unit model eliminated uniforms to reduce barriers with inmates. The 1970s brought back olive tunics and regalia for esprit de corps. Each change split staff or delivered limited impact.

Uniforms, the review found, express philosophy, build cohesion and shape how authority is exercised.

This forgotten analysis reveals why the clothes on a guard’s back matter for safety inside Canada’s prisons and beyond.