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Persuading People in Peril: The Cape Town Experiment

My daughter—a socio-behavioural scientist at the University of Cape Town’s Desmond Tutu HIV Foundation—alerted me last April to a possible crisis. Cape Town’s reservoirs were perilously low. Without replenishment from June-to-August winter rains the city could, reports indicated, “really run dry.”


Alas, in this new era of climate change, the hoped-for rains never came. Cape Town, with its nearly 4 million residents, was at risk of becoming the world’s first major city to run dry.


In September, with reservoirs at one-third their capacity, residents were asked to limit their water use to 23 gallons per day per person. But in a real life demonstration of the Tragedy of the Commons, fewer than half met the goal—each reasoning that their comparatively minuscule water use didn’t noticeably affect the whole city.

To heighten motivation, Cape Town Mayor Patricia de Lille attempted fear-based persuasion. “Despite our urging for months, 60 per cent of Capetonians are callously using more than 87 litres per day,” she explained at a January press briefing. “We have reached a point of no return. Day Zero is now very likely.” After the initially predicted Day Zero, April 11th, water taps would continue to flow only in the impoverished informal settlements (which use little water per person), in certain vital facilities, and via public taps in 200 designated locations where residents could line up with jugs. Yikes! What would this mean for life, work, and civic order?


With fears of the looming threat aroused, conservation norms became more salient. (My daughter recycles her laundry water for her very occasional toilet flushes, adhering to the new Cape Town norm: “If it’s yellow let it mellow.”) To activate and empower conservation norms, Capetonians have used all available media to share water conservation strategies (as if mindful of Robert Cialdini’s research on the power of positive conservation modeling). On a Facebook “Water Shedding Western Cape” group, 132,000 people are sharing tips. Even in workplace and restaurant bathrooms, signs now encourage not-flushing.


And to reduce “diffusion of responsibility” (as in the famed bystander nonintervention experiments), the city has posted an online “City Water Map” that can zoom down to individual households and reveal whether their water usage is within the water restriction limit (dark green dot). The effort is not intended to “name and shame,” but rather “to publicize households that are saving water and to motivate others to do the same.” Let’s “paint the town green,” urges Cape Town’s mayor.


Will this social influence campaign—combining fear arousal, social norms, and accountability—work? Time will tell. Recent declining domestic and agricultural water consumption enabled Day Zero to be pushed out to June 4th, by which time we can hope that winter rains will be replenishing those thirsty reservoirs . . . and that, thereafter, continuing water conservation can prevent future Day Zeros.

Source: macmillan psych community