Employing choice architecture to nudge consumers towards desirable behaviors
The world is falling short of the Paris Climate Agreement’s goal to limit global temperature rise to 2°C by the end of the century. One approach to slow global warming and reduce net greenhouse gas emissions is carbon offsetting, which negates CO2 emitted by one source by avoiding its release elsewhere. This research investigates how to nudge consumers to purchase carbon offsets when engaging in high-carbon footprint activities, such as flying on a plane.
I hypothesize that framing carbon offset costs as a percentage of flight cost will lead more consumers to opt to offset their carbon footprint, compared to when offset costs are presented as a monetary sum. However, this framing effect is only effective if the offset is a small percentage of total service cost (ie. between 1-2%). Three studies provide support for this hypothesis. In all studies, the dependent variable was whether participants indicated they would donate to offset their carbon footprint after buying a flight ticket.
Study 1 (N=149) asked participants to consider they had bought a flight ticket costing $350. Participants in the Control condition were asked if they would donate $4.99, while the Percentage condition asked if they would donate 1.43% of their flight cost to offset their carbon footprint. 55% of Percentage condition participants opted to donate, compared to 42% in the Control condition.
Study 2 (N=488, pre-registered) replicated Study 1. Participants in the Percentage condition were significantly more likely to donate (54%) than in the Control condition (42%).
A 2x2 design (Study 3, N=229) allocated participants to a Control/Percentage condition, and a High/Low Price condition. They were told that the flight cost either $250 or $500, and the $5 donation was reframed as either 2% or 1% of flight cost. The High-Price condition replicated the earlier framing effect: 49% of Percentage condition participants opted to donate, compared to 39% in the Control condition. However, the effect was reversed in the Low-Price condition: fewer participants in the Percentage condition opted to donate (39%) than in the Control condition (46%).
The findings suggest that framing carbon offset costs as a percentage of flight cost can lead more people to opt to offset their carbon emissions, but only when the percentage is relatively small.