It Is Time to Monitor Police Closely: What Happens When Police Officers Wear Body Cameras

WSJ informs:

[I]n Rialto, Calif., where an entire police force is wearing so-called body-mounted cameras, no bigger than pagers, that record everything that transpires between officers and citizens. In the first year after the cameras' introduction, the use of force by officers declined 60%, and citizen complaints against police fell 88%.

What happens when police wear cameras isn't simply that tamper-proof recording devices provide an objective record of an encounter—though some of the reduction in complaints is apparently because of citizens declining to contest video evidence of their behavior—but a modification of the psychology of everyone involved.

The effect of third-party observers on behavior has long been known: Thomas Jefferson once advised that "whenever you do a thing, act as if all the world were watching." Psychologists have confirmed this intuition, showing that something as primitive as a poster with a pair of glaring eyes can make test subjects behave better, and even reduce theft in an area.