#243 2012 · Newcastle University (Nettle, Nott, Bateson) · Security / behavioral design
Newcastle cut bike theft 62% with a sign of eyes — then watched it move next door
the problem
Locks, cameras and warning signs weren't stopping campus bike theft
background
Newcastle University's campus bike racks suffered ongoing theft despite conventional deterrents like locks, cameras and warning signs, none of which had produced a measurable drop in incidents. Researchers Daniel Nettle, Kenneth Nott and Melissa Bateson, building on earlier findings that images of eyes make people behave more cooperatively even when no one is actually watching, wanted to test a much cheaper intervention: simply printing a picture of watching eyes.
A believable test needed real theft data, not self-reported behavior, and it needed a way to distinguish actual deterrence — fewer thefts overall — from mere displacement, the same thefts happening somewhere else, a distinction easy to miss if researchers measured theft only at the signed locations themselves.
what everyone would do
Install more locks, cameras and warning signs at the theft-prone racks -- the conventional deterrent toolkit, all of which had already failed to produce any measurable drop in campus bike theft before the researchers tried anything else.
what they saw
Nettle, Nott and Bateson saw that prior lab research on eye images influencing cooperative behavior might transfer to a real-world deterrence setting even without any actual surveillance behind it -- and, just as importantly, that measuring success only at the signed racks would be misleading if thieves simply moved to unsigned ones nearby, so the study was designed from the start to distinguish real reduction from mere displacement.
the move
In May 2011, researchers installed signs bearing a pair of staring eyes and the line 'Cycle thieves: we are watching you' above three bicycle rack locations on campus, then compared recorded thefts in the year before and the year after installation at both the signed racks and the many unsigned racks elsewhere on campus.
why it works
A printed image of watching eyes exploits an evolved, largely unconscious sensitivity to being observed, triggering more cautious behavior even though everyone involved could recognize, if they thought about it, that a poster isn't actually watching anyone -- which is why theft fell sharply exactly where the signs were posted. But because the underlying motivation to steal a bike hadn't changed at all, and unsigned racks elsewhere on campus offered the same opportunity without the cue, the deterred behavior didn't disappear, it relocated almost one-for-one to wherever the eyes weren't looking.
the payoff
Bicycle theft fell 62% at the three signed locations, but rose 65% at the unsigned racks across the rest of campus — a near-exact swap, with roughly the same number of fewer thefts at signed racks as additional thefts elsewhere, indicating the signs displaced theft rather than reduced it overall.
where it breaks
This mechanism only reduces the behavior it targets at the specific location it's applied to -- it does nothing to the underlying motivation, so any deterrent that isn't applied everywhere the threat can move to will just displace the problem rather than solve it, exactly what the near-exact swap between signed and unsigned racks demonstrated. It also likely loses potency with repeated exposure once a population realizes the eyes carry no real consequence, and it depends on the target population being subject to the same unconscious social-cue sensitivity the original lab studies measured, which may not hold for every population or every kind of rule-breaking.
what came after
The study is widely cited in behavioral-science and crime-prevention literature both as a demonstration that images of eyes can measurably change real-world behavior at near-zero cost, and, equally importantly, as a textbook caution against declaring victory from a localized intervention without checking for displacement — Newcastle nonetheless expanded the signage across all campus racks, and other operators, including a UK rail line, later trialed the approach.
references
- [1]'Watching eyes' reduce bike theftNewcastle University Press Office, 2013ncl.ac.uk
- [2]'Cycle Thieves, We Are Watching You': Impact of a Simple Signage Intervention against Bicycle TheftPLOS One, 2012journals.plos.org