Rule #7: Check Your Blind Spot

Have a positive net impact

ensure that the outcome is net-positive

Your campaign should be monitored for spillover to ensure that the outcome of the campaign is net-positive. Campaign “spillover”, is an unintended behaviour that is undertaken by the campaigns audience in addition to the targeted behaviour (Thomas & Sharp, 2013; Thørgersen, 1999; Guagnano, Stern, & Dietz, 1995).

Spillover can be positive or negative. Research has found that positive spillover most often occurs when the audience adopts positive behaviours that are no more significant and difficult to adopt than the campaigns target behaviour (Thomas & Sharp, 2013). Negative spillover can occur for a number of reasons including when the targeted behaviour change is not associated with the attitudes and values of the campaign; the financial savings of the targeted behaviour are spent on a detrimental behaviour; and the targeted behaviour becomes an excuse for a  negative behaviour (Thomas & Sharp, 2013; Thørgersen, 1999; Guagnano, Stern, & Dietz, 1995).

Once a campaign’s target behaviour has become a social norm, meaning the target behaviour is what is socially acceptable, spillover is not likely to occur (Thomas & Sharp, 2013).

Negative spillover can harm the campaign

It is important to understand your campaign’s spillover because it is not always positive. Unlike positive spillover, which may lead to the adoption of other desirable behaviour, negative spillover could be counterproductive to a campaign.

For instance, many people believe that they are “doing their bit” by changing to compact fluorescent light bulbs; however, the energy impacts are not always seen. This is because consumers have realized that the lights use less energy and cost less to leave on, so they often leave their lights on more than they would have with the incandescent light bulbs (Weathercocks and Signpost, 2008 pg. 24;Thomas & Sharp, 2013).

People also tend to do what other people are doing and will “boomerang” back towards the norm. When their original behaviour is more  desirable than the norm, negative spillover can occur (Schultz, Nolan, Cialdini, Goldstein &Griskevicius, 2007; Haines & Spear, 1996).  For example, if someone is shown the average kilometres of driving per week from their coworkers, and they drive fewer kilometres, they may start to drive more.

Design the campaign with spillover in mind and manage spillover as it occurs

Tip#1: Eliminate negative spillover in campaign design when possible

Spillover is difficult to anticipate; however measures can be incorporated into the planning and design stage of your campaign to identify and prevent some negative spillover. Your campaign’s impact should be assessed if measures to mitigate negative spillover are unavailable. Campaigns with a net-negative impact will need to be redesigned or eliminated whereas campaigns with a net-positive impact will only need to monitor the unaddressed negative spillovers.   Once your campaign’s target behaviour has become a social norm spillover is not likely to occur (Thomas & Sharp, 2013).

Tip#2: Try counterarguing to avoid negative spillover

Your campaign can address common misconceptions and mistakes by counterarguing them and/or by changing the balance between personal cost and benefit (Thørgersen, 1999). A campaign that counterargues presents people with persuasive information, such as core facts, explicit warnings, and alternative explanations, that are needed in order to correct the target audience’s misconceptions or mistakes (Thørgersen, 1999; Cook & Lewandowsky, 2011).

Tip#3: Use positive and injunctive norm messages

To mitigate the “boomerang effect”  your campaign should use positive and injunctive norm messages that align with the descriptive norm message (Thomas & Sharp, 2013; Schultz, Nolan, Cialdini, Goldstein &Griskevicius, 2007; Perkins, Linkenbach, Lewis, & Neighbors, 2010).

Injunctive norms are the perceptions of “what is commonly approved or disapproved of” (Schultz, Nolan, Cialdini, Goldstein, &Griskevicius, 2007, p. 430); and descriptive norms are the perceptions of “what is commonly done in a situation” (Schultz, Nolan, Cialdini, Goldstein, &Griskevicius, 2007, p. 430). Descriptive norms have magnetic tendencies that can influence an individual with desirable behaviour to move in a negative direction towards the norm; however, when it is used in combination with injunctive norms the magnetic tendencies apply only to the less desirable behaviour (Schultz, Nolan, Cialdini, Goldstein, &Griskevicius, 2007). Positive messages are stronger than negative or fear-based messages as the latter can reinforce the prevalence perceptions of the targeted behaviour (Perkins, Linkenbach, Lewis, & Neighbors, 2010).


Ex#1: Tide cold water

Before Tide introduced its cold water detergent, it was commonly understood that warm water cleaned clothes better than cold water. So, as Tide introduced its cold water detergent to the public it had to explain to them that its cold water detergent formula performed as well as when clothes were washed with detergent in warm water  (Health Care Communication News, 2007). Tide also changed the balance between personal cost and benefit by highlighting that switching to cold water conserved money because it was more energy efficient and gentler on peoples clothes (Health Care Communication News, 2007). Tide recognized that these measures could be incorporated into their Take a Load Off campaign early on (P&G, 2012); however, Tide could have still added the measures in at a later time once spillover became problematic to their campaign.


Opower is an organization that works with utilities companies to help their customers lower their energy usage. They do this by producing a report for these customers that shows them their energy usage compared to their neighbours. This is a fantastic way to convince people who have above average energy usage tendencies to use less, and get closer to average. However, Opower saw an initial “boomerang effect” of those with below average energy use. They were not motivated to go above and beyond to reduce energy consumption, instead they saw some leeway for them to use a bit more energy in order to be average. To combat this problem, Opower used a positive norm message. For the people that were doing well, they added a smiley face to their reports, implying that they were performing better than their neighbours. The simple addition of a smiley face was enough of a change to encourage people that they were doing what they should be doing, and maintain their low energy use (Ravindranath, 2013).

So remember: Have a positive net impact

Negative spillover is counterproductive to your behaviour change campaign. Measures are available to campaigns that address counterproductive spillover linked to either misconceptions or the “boomerang effect”. These measures include counterarguing misconceptions and/or changing the balance between personal cost and benefit and using positive and injunctive norm messages that align with the descriptive norm message. If other negative spillover is present it is important that you assess the impact that it has on the behaviour change campaign. A behaviour change campaign should have a net-positive impact; if it doesn’t, the campaign should be restructured or eliminated as it is doing more harm than good.



Cook, J., Lewandowsky, S. (2011), The Debunking Handbook. St. Lucia, Australia: University of

Queensland. November 5. ISBN 978-0-646-56812-6. []

Guagnano, G. A., Stern, P. C., & Dietz, T. (1995).Influences on Attitude-Behaviour Relationships. Environment and Behaviour , 27 (5), 699-718.

Haines, M., & Spear, S. F. (1996).Changing the perception of the norm: a strategy to decrease binge drinking among college students. Journal of American college health , 134-140.

Health Care Communication News. (2007, August 3). Tide cleans up with Web campaign. Retrieved December 2013, from Ragan’s Health Care Communication News:

P&G. (2012, April 2). P&G “Take a Load Off” Campaign, Together with Actress Vanessa Lachey, Empowers Consumers Nationwide to Switch to Cold Water Laundry Washing This Earth Day. Cincinnati, Ohio, United States of America.

Perkins, W. H., Linkenbach, J. W., Lewis, M. A., & Neighbors, C. (2010). Effectiveness of social norms media marketing in reducing drinking and driving: A statewide campaign. Addictive Behaviors , 35, 866-874.

Ravindranath, M. (2013, November)  Opower keeps improving it’s message to get people to use less energy. Retrieved from

Schultz, P. W., Nolan, J. M., Cialdini, R. B., Goldstein, N. J., &Griskevicius, a. V. (2007). The Constructive, Destructive, and Reconstructive Power of Social Norms.PsychologicalScience , 429-434.

Thomas, C., & Sharp, V. (2013).Understanding the normalisation of recycling behaviour and its implications for other pro-environmental behaviours: A review of social norms and recycling. Resources, Conservation and Recycling , 79, 11-20.

Thørgersen, J. (1999). Spillover processes in the development of sustainable consumption pattern. Economic Psychology , 20, 52-81.

Tide. (2011, June 2). Tide Coldwater Detergent. Retrieved December 2013, from YouTube:

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