Take Me with You! Economic Incentives, Nudging Interventions, and Reusable Shopping Bags: Evidence from a Randomized Controlled Trial

Little is known about the impact of policy interventions other than taxes and bans to reduce the demand for single use plastic bags. More specifically, the influence of environmental nudges and financial bonuses to curb the single use plastic bag purchase and consumption is largely understudied. To fill this gap, we run an RCT with loyalty card holders of one of the biggest supermarket chains in Yerevan (Armenia) to test and compare interventions based on environmental nudges and financial bonuses. We manipulate the type of the intervention – either a financial bonus or a nudge –, the presence of a reusable bag – either provided for free or not provided –, and the size of the bag – either small or big. Compared with the baseline setting with no intervention, both the financial bonus and the environmental nudge serve as effective policy instruments to reduce disposable plastic bag purchase. Moreover, reusable bags in combination with the environmental nudge or the financial bonus are more effective than the environmental nudge or the financial bonus alone. Finally, the financial bonus is substantially more effective than the environmental nudge, irrespective of the absence/presence of reusable bags.