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Litter on the streets encourages stealing, street cleaners promote helpfulness

07 October 2010

The influence of rules on our behaviour is determined to a significant degree by the environment. Evidence of norm-transgressing behaviour, for example graffiti and litter on the streets, encourages the breaking of other rules, such as ignoring prohibitive signs and even stealing. This has been revealed by research conducted by psychologist Kees Keizer, who will be awarded a PhD by the University of Groningen on 14 October 2010.

The research, some of which has been published in the renowned journal Science, not only shows that disorder is catching but that the same applies to order. For example, it turns out that street cleaners can increase the helpfulness of people. The research also shows that prohibitive signs can have an adverse effect and that it is crucial for managers to obey the rules.

Norm transgression is catching

Policy directed towards the reduction of norm-transgressing behaviour relies to a large extent on the deterrent effect of sanctions. This is too one-sided, however – whether or not you obey rules turns out to be determined to a significant degree by signals conveying the degree to which others respect the rules. A series of experiments in the public domain revealed that observing the norm-transgressing behaviour of others, or the evidence of this behaviour, encourages people to misbehave too. For example, the number of people who stole an envelope containing money doubled if there was graffiti or litter nearby. In other words, one norm transgression leads to another. This effect is strengthened if the observed norm transgressors have a high status. It is thus essential that this group in particular obeys the rules. A director who commits fraud is a very influential norm transgressor.

Prohibitive signs have the opposite effect

Prohibitive signs are usually used to draw extra attention to familiar rules. This is usually in an environment where many people do not obey these rules. However, situating such signs in these environments has the opposite effect. They draw extra attention to the norm-transgressing behaviour! Putting a ‘Don’t throw litter on the street’ sign in an environment where there is a lot of litter not only results in more litter, it also encourages an increase in other norm-transgressing behaviour.

Spotlight desired behaviour

The same applies to order as to disorder – observing someone who clearly respects a norm encourages other norm-conforming behaviour. It turns out that the number of people who helped someone who had dropped their shopping nearly doubled if they had seen a pavement cleaner just before. This not only demonstrates that a single person can have a positive effect, it also opens up opportunities for policy. The researcher gives the example of the municipal cleaning service that cleans the city at the crack of dawn. Keizer: ‘This cleaning service misses its positive effect because no-one sees it at work. The work should be more visible!’

SIRE adverts ineffective

Not only policy but also campaigns could be much more effectively designed. In current campaigns people are often shown misbehaving, i.e. that this is why there is a problem. The SIRE foundation regularly airs television adverts highlighting undesired behaviour, for example ‘Nice people and how to deal with them’ and ‘Short fuse’, where aggression was the topic. The research demonstrates that this is the wrong approach because you are then encouraging norm-transgressing behaviour. Keizer: ‘What you should be showing is people demonstrating the desired behaviour.’

Curriculum vitae

Kees Keizer (Leeuwarden, 1975) studied psychology in Groningen. He conducted his PhD research at the department of Social Psychology of the University of Groningen and within the ICS research school. His supervisors were Prof. S. Lindenberg and Prof. L. Steg. Keizer is currently a lecturer at the Faculty of BSS at the University of Groningen. The title of his thesis is ‘The spreading of disorder’.

Note for the editor

Contact: Kees Keizer  

Last modified:13 March 2020 01.57 a.m.
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