It is natural for humans to want to remain consistent in terms of how we look and what we do.

Once we’ve taken a stand, we face personal and social pressure to behave consistently with that commitment. These pressures make us act in ways that justify our earlier decision.

Psychologists understand the power of consistency in directing human action. Eminent theorists have also considered the desire for consistency as a central motivator of our behaviour. Good personal consistency is a highly valued character trait in our culture. Individuals whose actions match their words  appear to be honest and morally sound. In comparison, those who behave inconsistently appear to be untrustworthy and treacherous.

While consistency has a formidable power to drive human action, it’s commitment that sets the stage for consistency. Commitment refers to how we want to be consistent with what we say we will do, who we say we are. Verbalised, written, public commitments reinforce our identities and self-image, significantly shaping our behaviour. When a person is asked to commit to an idea or action by making an agreement, a subtle shift occurs in their attitude toward it. This shift in attitude makes that person to act with consistency.

Commitment strategies have proven to be effective in promoting diverse range of sustainable behaviour. Here are few examples:

To promote bus ridership, individuals who didn’t travel by bus were assigned to one of four conditions. In Information condition, participants were provided a route, schedule and identification card to monitor their ridership. In Commitment condition, participants verbally pledged to ride a bus twice a week for four weeks. In Incentive condition, participants were provided 10 free bus tickets and informed they would receive more tickets provided they used earlier tickets. And in Combined condition, participants verbally pledged to ride twice a week for four weeks and received free tickets.

After two follow-ups conducted at three and 12 weeks after the launch, all four conditions were found to increase bus ridership. Interestingly participants in Commitment condition rode the bus just as frequently as the participants in other conditions. This is because of our desire to honour and act consistently with our commitment.

Bus Ridership: Sustainable Behaviour

Bus ridership: sustainable Behaviour

In another example, Salt Lake City increased curbside recycling by obtaining written commitments from the residents, as opposed to by distributing flyers, making telephone calls or contacting them in person.

Paper recycling increased to 47 per cent in a nursing home in Portland Oregon when residents were informed of the economic and environmental benefits of recycling and asked to sign a group commitment form and to pledge to recycle for the next four weeks.  Recycled paper was measured during the information and commitment period and over the four weeks after the commitment period to gather an objective measure of the behaviour change. The increase in recycling continued during the four-week follow-up period even though residents knew they had completed their initial commitment.

In addition to written and verbal pledges, commitment can also be increased through active involvement. In research carried out by Pacific Gas and Electric, trained home assessors used various commitment strategies to persuade householders to weatherstrip their homes. Assessors asked householders “When do you think you’ll have the weather stripping done?” and promised to follow up around that time. Assessors involved the homeowners by having them inspect the insulation level in their attic, check for uninsulated water heaters and so on. This way of presenting the assessment and involvement significantly increased the likelihood that householders would weatherstrip their homes.

These examples clearly illustrate how consistency and commitment are effective levers to increase public participation in diverse range of sustainable activities. Government and corporate organizations can explore these tools to nudge people toward sustainable behaviour.