Behaviour Change for Sustainability: Keeping Promises: Do Pledges Work?

"A popular component of many behaviour change efforts involves asking a person to make a commitment, or “pledge”, to undertake the desired behaviour. This typically involves getting them to sign their name to a promise to save water/energy/emissions. The common perception is that this will make them more accountable, and thus more likely to follow through on the requested behaviours. This months article asks the question as to whether the commitment approach actually works, and if so, how and why?

There is a certain amount of evidence across a variety of settings to suggest that gaining a commitment does indeed have an effect on behaviour. For example, strong support has been found for the effectiveness of “promise cards” to encourage people to wear seatbelts, discussed in a 1991 review by Geller and Lehman. In a series of studies, drivers were asked to sign a written statement of commitment to use seatbelts for a period of time (1-2 months). Subsequently, the researchers found that “In every case, a significant number of promise-card signers increased their use of safety belts”. More importantly, the effects of this intervention were found to be more effective in influencing lasting change than similar approaches which used incentives to entice people to wear seat belts.

In the environmental field, the results are similarly compelling. A couple of studies have shown the effect of commitment on recycling behaviour. Pardini and Katzev conducted a simple study where groups of households were either a) given an information leaflet about recycling, b) asked to make a verbal pledge to recycle, or c) asked to make a written pledge. Both groups which made the pledge showed higher recycling behaviours, with the written pledge resulting in the strongest, most enduring behaviour change.

As with all behaviour change efforts, it is important to consider if the intervention is likely to make a difference long-term, rather than just for the duration of the intervention. A 1990 study in a retirement home found that residents asked to sign a 4-week group commitment increased their recycling by 47%. When the researchers checked in after another 4 weeks, this increase had been maintained. The same study also looked at recycling behaviour of a group of students and found that both individual and group pledges worked to change behaviour, but only those students who signed individual pledges maintained the change over a follow-up period. This study echoed the seatbelt finding mentioned above, that signing a commitment is a more powerful facilitator of long-term change than providing incentives.

So it appears that gaining a commitment from people is a worthwhile, and fairly cost-effective, step in increasing the likelihood that behaviour change efforts will be effective. It is worth considering why commitments work. The theory of “Personal Norm Activation” suggests that, once we have committed to a course of action, we have cemented it as a personal norm, or something that we see as a moral standard in ourselves. Any action which is at odds with that commitment therefore triggers a personal norm, providing a motivation to act.

Similarly, the theory of Cognitive Dissonance, which has been discussed at length in previous issues of Wake-Up Call, goes some way to explaining the effectiveness of commitments. When we perceive a misalignment between our actions and our beliefs or values, then we experience discomfort and/or confusion. Thus, we work hard to maintain “cognitive consistency”. Making a commitment serves to create a belief that we are on board with the behaviour being proposed, so we do our best to ensure that our actions match this belief we have about ourselves.

This process does, however, rely on us being self-aware - of our commitments, our behaviour, and any misalignment between them. If we are not conscious of our behaviour in relation to our beliefs, then dissonance is unlikely to occur, thus removing the motivating factor. This is one reason why highly habitual behaviour (which tends to occur at an unconscious, “auto-pilot” level) is more resistant to the effects of commitments. This phenomenon is discussed at length by Matthies and colleagues, who states that “when car use habits are strong, the whole process of norm activation and evaluation is blocked, and situational cues will lead directly to the habitualised choice of travel mode, without moral or other motives being considered”. As a result, it is suggested that some form of habit disruption is combined with the commitment, as demonstrated by the Matthies team. (Habits are also discussed in a previous Wake-Up Call).

Reviewing the evidence for the inclusion of commitments or pledges as part of a behaviour change interventions, a few recommendations can be made
· Public commitments appear to work better than private ones
· Try to get written, specific commitments, rather than vague verbal ones
· A combination of individual and group pledges is ideal if possible, so that people can hold each other accountable, while also taking personal responsibility
· Ensure that people are aware, conscious and reminded of their commitment and their behaviour

Finally, as always, this approach is best used in combination with other tactics, including a thorough consideration (and removal where possible) of real and perceived barriers to the desired behaviour."

This article was sourced from Awake -
Awake provides psychology-based services to support the development of sustainable behaviour in individuals, groups and organisations. Visit www.awake.com.au for more info