Editing Broken windows theory (section)

===Netherlands===
In 2007 and 2008, Kees Keizer and colleagues from the [[University of Groningen]] conducted a series of controlled experiments to determine if the effect of existing visible disorder (such as litter or graffiti) increased other crime such as theft, littering, or other [[antisocial behavior]]. They selected several urban locations, which they arranged in two different ways, at different times. In each experiment, there was a "disorder" condition in which violations of social norms as prescribed by signage or national custom, such as graffiti and littering, were clearly visible as well as a control condition where no violations of norms had taken place. The researchers then secretly monitored the locations to observe if people behaved differently when the environment was "disordered". Their observations supported the theory. The conclusion was published in the journal [[Science (journal)|''Science'']]: "One example of disorder, like graffiti or littering, can indeed encourage another, like stealing."<ref>{{cite journal |doi=10.1126/science.1161405 |last1=Keizer |first1=K |last2=Lindenberg |first2=S |last3=Steg |first3=L |s2cid=7881039 |title=The Spreading of Disorder |journal=Science |volume=322 |issue=5908 |pages=1681–1685 |year=2008 |pmid=19023045 |url=https://pure.rug.nl/ws/files/10429297/KeizerK-Spreading-2008.pdf |bibcode=2008Sci...322.1681K |access-date=2019-08-16 |archive-date=2019-04-29 |archive-url=https://web.archive.org/web/20190429002522/https://pure.rug.nl/ws/files/10429297/KeizerK-Spreading-2008.pdf |url-status=live }}</ref><ref>{{cite news |url=http://www.economist.com/science/displaystory.cfm?story_id=12630201 |title=Can the can |access-date=2008-11-24 |newspaper=The Economist |date=2008-11-20 |archive-date=2008-12-02 |archive-url=https://web.archive.org/web/20081202013436/http://www.economist.com/science/displaystory.cfm?story_id=12630201 |url-status=live }}</ref>