Responding Linearly in Nonlinear Problems: Application to Earth’s Climate

Past research has shown that a majority of people exhibit robust linear thinking for nonlinear changes in their decision environment. We argue that linear thinking could be particularly problematic in the case of interpreting carbon-dioxide’s (CO2) lifetime in the earth’s atmosphere. Participants from policy and non-policy backgrounds were asked to rank five ranges of CO2 percentages to be removed from the atmosphere according to their impact on CO2’s lifetime in two separate conditions: Aid and no-Aid. In the Aid condition, participants were provided with a descriptive decision aid through instructions that might enable them to answer the problem correct, while this aid was absent in the no-Aid condition. Two problems were presented to each participant in random order: Linear, where a ranking based upon linear thinking yielded a correct rank order; and Nonlinear, where a ranking based upon linear thinking yielded an incorrect rank order. Results reveal that a majority of participants from both backgrounds responded linearly on both problems and although the decision aid had no effect on participants’ correct responses, it enabled policy backgrounds to move away from responding according to linear thinking. We discuss implications of these findings on policy making about climate change.